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DMU380ZA Series USER MANUAL

1. eeseseeeerm 40 5 7 3 Rate Sensor Scaling Low Pass Filter cccccccccccccccceeeeeeeeeesssesseeeeeeeeees 4 5 7 4 Magnetic AToDrelib csse iio siso seia soon ce PU Co noir emp XD dae rae UU AR aa 42 Jo DUO Operio n es neto ia avalia tes ne en yee ene ee eter Un eT 43 6 DMU380 UART Port Interface Definition esses 46 Gl GIC IS PIU NR 46 02 N mber Formal ioga de asi da dd 46 oo e oM gl 0 00 17 Romer e A E eer er trnrrest erin tert 47 Ol Packet Headin EEEE 47 Do PO INDO 2202999955529 9902995 28 92 29 09 0 09 5 40 59 0000 999 5096 a seas 47 Ces Fe MEM cler BT 48 ES MEME Cero s 48 Go Cono Ot 6 COMU H 48 696 Messasime OV CIVIC uoucmusiesnsdenve sic unenvaschtabU auc En tev sei dte MR Ea V ad E Su a CER sia 48 7 DMU380 Standard UART Port Commands and Messages seseeseese 51 ERES Wi RR RR E RR EA E 51 UN MEME Dino COMMING Uc 51 Tke M RN T UU UN 51 LLS Ebo COMA O Re AGA 51 Vb CUO TR CS PO ecco os css E SE EE sad 51 ka dnteracave COMMAS eigr O n 51 C NEMESIS RES 51 7 2 2 Algorithm Reset Command sse nnne 52 1 2 3 Algorithm Reset RESPONSE iet eria ro IU iani on EXER r0 inienn iiki anani 52 FN MEG CIS VHC UT 52 7 2 5 Calibrate Acknowledgement Response eeeeeeee 53 7 2 06 Calibration Completed Parameters Response eeeseeeeeeee 53 Page ii Doc 7430 3810 Rev 02 DMUS380ZA Series U
2. Doc 7430 3810 Rev 02 Page 30 DMU380ZA Series User s Manual MEMSIC When not in distorted magnetic environment M EXAMPLE Figure 8 shows a typical flight profile of the fixed wing aircraft and the corresponding advanced settings that one can configure adaptively depending on a flight phase Prelaunch is the phase of flight in which an aircraft goes through a series of checkups hardware and software on the ground before takeoff The aircraft is a static condition Takeoff is the phase of flight in which an aircraft goes through a transition from moving along the ground taxiing to flying in the air usually along a runway The aircraft is under horizontal acceleration and may suffer from vibrations coming from an engine and ground contact forces transmitted from its landing gear Climb is the phase of a flight after take off consisting of getting the aircraft to the desired flight level altitude More generally the term climb means increasing the altitude The aircraft 1s under vertical acceleration until it reaches the steady state climb rate Straight and level flight is the phase of flight in which an aircraft reaches its nominal flight altitude and maintains its speed and altitude The aircraft is under equilibrium See Figure 8 Maneuver is the phase of flight in which an aircraft accelerates decelerates and turns The aircraft is under non gravitational acceleration and or deceleration See Figure 8 Des
3. DMU380ZA Series User s Manual MEMSIS gt DD RM Pic and eain NENNEN INS380ZA 9 DOF IMU 3 Axis Internal Magnetometer and external Read 3 1 3 2 3 3 3 4 and 3 5 GPS Receiver Position Dynamic Velocity Roll Pitch and Heading Figure 3 shows the DMU380ZA Series hardware block diagram At the core of the DMU380ZA Series is a rugged 6 DOF Degrees of Freedom MEMS inertial sensor cluster that is common across all members of the DMU380ZA Series The 6 DOF MEMS inertial sensor cluster includes three axes of MEMS angular rate sensing and three axes of MEMS linear acceleration sensing These sensors are based on rugged field proven silicon bulk micromachining technology Each sensor within the cluster is individually factory calibrated using MEMSIC s automated manufacturing process Sensor errors are compensated for temperature bias scale factor non linearity and misalignment effects using a proprietary algorithm from data collected during manufacturing Accelerometer and rate gyro sensor bias shifts over temperature 40 C to 71 C are compensated and verified using calibrated thermal chambers and rate tables The 6 DOF inertial sensor cluster data is fed into a high speed signal processing chain which provides the sensor compensation and digital filtering The processor also calculates attitude and navigation data for the appropriate models VG AHRS and INS Measurement data packets are available at fixed continuous output rates
4. MEMSIC fff8fff70000002d41900288a360300 a3ad invalid preamble type length 001bffdf3a5b fffe0000ffea fff8fff7f337 0015fda9fd4f 00000000000000000000 2d19 00288a3e 0300 Hex Value Data g FFF8 0 0024 FFF7 0 0027 F337 0 9988 Hex Value Data m s 0015 0 164 FDA9 4 680 FD4F 5 383 Angles Value Data deg 0 148 0 181 82 062 Angular Rates Value Data deg s 0 04 0 42 GPS Hex Data 00000000 0 000000000 Rad 00000000 0 000000000 Rad Hex Value Data deg C 2D19 35 233 Hex Data Value s 00288a3e 2656830 BIT status Field Field masterFail 0 LT o emm o mme o EO shes o meme o me oo Figure 32 Example payload from Nav Data Packet 1 N1 Doc 7430 3810 Rev 02 Page 104 DMU380ZA Series User s Manual MEMSIZ MEMSIC 1759 McCarthy Blvd Milpitas CA 95035 Phone 408 964 9700 Fax 408 854 7702 Website www memsic com Email infoca memsic com Doc 7430 3810 Rev 02 Page 105
5. return 0 empty buffer Doc 7430 3810 Rev 02 Page 96 DMU380ZA Series User s Manual MEMSIC find header for n mToPop 0 numToPoptlsSize queue ptr f numroPopt l if 0x5555 peekWord queue ptr numToPop break Pop queue ptr numToPop LE Oize queue ptr lt 0 header was not found return 0 make sure we can read through minimum length packet if Size queue ptr lt 7 return 0 get data length 5th byte of packet dataLength peekbyte queue ptr 4 make sure we can read through entire packet LE Size queue ptr lt 7 dataLength return 0 check CRC myCRC calcCRC queue ptr 2 dataLengtht3 packetCRC peekWord queue ptr databengtht5 if myCRC packetCRC bad CRC on packet remove the bad packet from the queue and return Pop queue ptr dataLength t7 return O fill out result of parsing in structure result packet type peekWord queue ptr 2 result gt length peekByte queue ptr 4 Doc 7430 3810 Rev 02 Page 97 DMU380ZA Series User s Manual MEMSIC result crc packetCRC for counter 0 counter lt result gt length counter result e data counter peekByte queue ptr Stcounter Pop queue ptr databengthb t return 1 KKK KKK KK KKK Ck kk kk CK KK Kk kk Kk KK kk KK Ck Ck Ck kCk ck ck ck k ck ck k ck ck ck k ck ck k ck ck ck ck ck ck kk k ko k kk k
6. The following paragraph heading formatting is used in this manual 1 Heading 1 1 1 Heading 2 1 1 1 Heading 3 Normal Page vi Dock 7430 3810 Rev 02 DMU380ZA Series User s Manual MEMSIC 1 Introduction 1 1 Manual Overview This manual provides a comprehensive introduction to MEMSIC s DMU380ZA Series Inertial System products Dynamic Measurement Unit 380ZA For users wishing to get started quickly please refer to the two page quick start guide included with each evaluation kit shipment Table 1 highlights the content in each section and suggests how to use this manual Manual Section Section 1 Manual Overview Section 2 Interface Section 3 Theory of Operation Section 4 Application Guide Section 5 SPI Port Interface Section 6 9 UART Port Interface Doc 7430 3810 Rev 02 Table 1 Manual Content Who Should Read All customers should read sections 1 1 and 1 2 Customers designing the electrical and mechanical interface to the DMU380ZA series products should read Section 2 All customers should read Section 3 As the DMU380ZA Series products are inter related use the chart at the beginning of Section 3 to ensure that you get an overview of all of the functions and features of your DMU380ZA Series system For example if you have purchased an INS380ZA you should read not only the section on the INS380ZA but also familiarize yourself with the theory of operation for the IMU380ZA VG3
7. 5 Hz Bartlett 10 Hz Bartlett Magnitude dB 20 Hz Bartlett 40 Hz Bartlett Frequency Hz Figure 14 DMU380ZA Bartlett Filter Response 9 4 Magnetic Alignment On models with magnetometers and AHRS or INS algorithms INS380ZA and AHRS380ZA the system is capable of compensating for the hard iron bias and soft iron scaling of the mounting environment Once found the values are used by the Kalman filter algorithm to compensate the heading for the magnetic environment A complete Doc 7430 3810 Rev 02 Page 42 DMU380ZA Series User s Manual MEMSIC gt discussion of the process is discussed in the section Mag Alignment Procedure found in Appendix A Installation and Operation of NAV VIEW To initiate a magnetic alignment over the SPI bus perform a write to register 0x50 by appending the write bit address combination with 0x01 e g OxDOO1 Table 29 provides a description of the mag alignment register Table 29 Magnetic Alignment Register Base Address 0x50 Read Write Description Default 0x0000 15 8 Mag Align Initiation byte 7 0 Mag Align Status byte 0x00 Disabled default 0x0B Alignment process complete 0x0C Alignment process in progress Once the mag align procedure has begun the Mag Align Status byte will be set to OxOC The master must monitor the least significant byte of register 0x50 to assess test status Once the byte changes to OxOB the alignment procedure is complete At
8. Baud Rate External GPS L Product Configuration Print Preview O Internal GPS External Aiding L Contains Mags O algorithm Enabled Firmware P Architecture IL Heading Track Offset Turn Switch Threshold Hardware Status Enable Fields L Unlocked 1PPS O Unlocked Internal GPS Magnetometers Parameters X hard iron offset Y hard iron offset Saft iron ratio GPS Baud GPS Protocol MUser Behavior switch Axes Orientation Customer Axes Unit Reference Axes O No DGPS O Unlocked Eeprom Software Status Enable Fields O Freely Integrate O Use Mags O Use GPS O Stationary Yaw Lock Restart Over Range O Dynamic Motion O Algorithm Initializing O High Gain O Altitude Only Alg L Turn Switch Sensor Status Enable Fields O Sensor Over Range Filter Clock Rate FilterClocks FilterClock 1 FilterClock2 FilterClock3 LP Cutoff H2 _ Comm Status Enable Fields O No External GPS Figure 29 Read Configuration Doc 7430 3810 Rev 02 Page 92 DMU380ZA Series User s Manual MEMSIC gt Appendix B NMEA Message Format The GPS receiver outputs data in NMEA 0183 format at 9600 Baud 8 bits no parity bit and 1 stop bit The GGA and RMC message packet formats are explained in this section GGA GPS fix data Time and position together with GPS fixing related data
9. Doc 7430 3810 Rev 02 Page 69 DMU380ZA Series User s Manual MEMSIS gt This command allows the user to get the unit s current configuration fields NumFields is the number of fields to get The fieldo fieldl etc are the field IDs to get GF may be used to get configuration calibration and algorithm fields from RAM Multiple algorithm fields will not necessarily be from the same algorithm iteration If at least one field is successfully collected the unit will respond with a get fields response with data containing the field IDs of the successfully received fields If any field 1s unable to be received the unit will respond with an error response Note that both a get fields and an error response may be received as the result of a get fields command GF Payload Contents Byte Offset 0 numFields U1 The number of fields to get A fed U2 f The firstfield IDtoget 3 feat U2 f jThesecndfeldiDtoge e Morefield Dstoget numFiels2 1 Field U2 f Thelastfield IDtoget 0 12 Get Fields Response Get Fields GF 2 0x4746 Packet Type Length Payload 0x5555 0x4746 1 numFields 4 lt GF Data gt lt CRC U2 gt The unit will send this packet in response to a get fields request if the command has completed without errors GF Payload Contents Byte Offset 0 nmrs Ut Thenumberoffelisretieve 1 field0 U2 Thefistfield ID retrieved HU field Da
10. Each external device has an associated message with low level error signals The comError flag in the BITstatus field is the bit wise OR of this comBIT field Doc 7430 3810 Rev 02 Page 74 DMU380ZA Series User s Manual MEMSIC gt Table 45 DMU380 COM BIT Field comBIT Field Bits Meaning Category _serialAEror OO normal t error Soft Reseved de NA 97 comSerialABIT Field The comSerialABIT field See Table 46 contains flags that indicate low level errors with external serial port A the user serial port The serial AError flag in the comBIT field is the bit wise OR of this comSerialABIT field Table 46 DMU380 Serial Port A BIT Field comSerislABITField Bits Meaning Category tronsmitBuferOvertow 0 O normal t overflow Soft breakDetect parityError Reserved 15 NA 0 9 8 comSerialBBIT Field The comSerialBBIT field See Table 47 contains flags that indicate low level errors with external serial port B the aiding serial port The serialBError flag in the comBIT field is the bit wise OR of this comSerialBBIT field Table 47 DMU380 Serial Port B BIT Field comSwiBBITFed Bis Meaning Tengo transmitBuferOverfow 0 O normal t overfow So Reewd o Qua 9 9 SsoftwareBIT Field The softwareBIT field contains flags that indicate various types of software errors See Table 48 Each type has an associated message with low lev
11. FUNCTION calcCRC calculates a 2 byte CRC on serial data using CRC CCITT 16 bit standard maintained by the ITU 5 International Telecommunications Union ARGUMENTS queue ptr is pointer to queue holding area to be CRCed il startIndex is offset into buffer where to begin CRC calculation num is offset into buffer where to stop CRC calculation RETURNS 2 byte CRC EOKCkCkCk kCkck ck k kk kk k ck kk k ck k kc k ck Ck k ck kk ck ck k ck ck ck k ck ck k kc k ck k kc k kk ck ck k kc k ck kc k ck kk ck ck k kc kckck ck ck kckckck ck kck kk kk unsigned short oaloCcRC QUEUE TYPE queue prr unsigned int startindex unsigned int num unsigned int i 0 j 20 unsigned short crc 0x1DOF non augmented inital value equivalent to augmented initial value OxFFFF for 105 3 nums i 1 4 cro peekByte queue ptr startlIndexti lt lt 8 for j 0 j 8 j 1 it ere amp 0x8000 cre cro lt lt 1 Oxl021 else crc crc lt lt 1 return crc KKK KR KKK KKK KK KK Ck KK KK KK Kk KK CK KK kk KKK Kk Kk Ck Ck Ck Kk kCk ck ck ck k ck ck k ck k ck k ck ck k kc k kk kk k FUNCTION Initialize initialize the queue ARGUMENTS queue ptr is pointer to the queue EOKCkCkCk kCkck ck k kk kk k ck kk k ck k kc k ck kc k ck kk k ck k ck ck kk ck ck k kc k ck k kc k ck kc k ck k kk ck k ck ck kk ck ck kk ck ck k ck ck kckckck kk ck kk kk void Initiasllze QUEUE TYPE dqueue ptr queue ptr gt count 0
12. queue ptr gt front 0 Doc 7430 3810 Rev 02 Page 98 DMU380ZA Series User s Manual MEMSIC queue ptr gt rear 1 KKK KK KK KKK KK KK Ck KK KK KK KK Kk KK KK KK kk KK KK KK kk ck Ck kCk kCk ck ck ck k ck ck k ck ck ck k ck ck k kc k ko k kk k FUNCTION AddQueue add item in front of queue ARGUMENTS item holds item to be added to queue queue ptr is pointer to the queue RETURNS returns 0 if queue is full 1 if successful ECKCkCkCk kCkck ck k kk kk k ck k kk ck kk ck ck Ck k ck kk k ck k kc k ck kk ck k kc k ck k kc k ck kc k ck k kc k ck kk ck kk ck ck k kc k ck k ck ck kckckck kk ck kk kk int AddOueue char item QUEUE TYPE queue ptr int retval 0 if queue ptr count gt MAXQUEUE retval 0 queue is full else queue ptr gt count queue ptr gt rear queue ptr gt rear 1 MAXQUEUE queue prtr centry queue pte gt rear item retval 1 return retval f RKCKCKCK kCKkCk kCkCkCk kk Ck kk kk kk KC kk KK kk KK kk Kk Ck Ck Ck ck ck kck ck k ck ck ck k ck ck k ck ck ck kc k ck kk ck ck k kk kk FUNCTION DeleteQeue return an item from the queue ARGUMENTS item will hold item popped from queue queue ptr is pointer to the queue BETURNS returns 0 if queue is empty 1 if successful KK kk kCk kk k ck kk ck ck kk ck kk k ck k kk ck k ck ck k kc k ck k kc k ck kc k ck kk Ck ck k kc k kk ck ck kk ck ck k ck ck k kc k ck k ck ck k ck kck k kck kk kk int DeleteQueue char item
13. 02 Page 66 DMU380ZA Series User s Manual MEMSIC gt 8 8 Commands to Program Configuration 8 6 1 Write Fields Command Write Fields WF 0x5746 Terminatio Preamble Packet Type Length Payload n 0x5555 0x5746 1 numFields 4 WF payload U2 gt This command allows the user to write default power up configuration fields to the EEPROM Writing the default configuration will not take affect until the unit is power cycled NumFields is the number of words to be written The field0 fieldl etc are the field IDs that will be written with the field Data field Data etc respectively The unit will not write to calibration or algorithm fields If at least one field is successfully written the unit will respond with a write fields response containing the field IDs of the successfully written fields If any field 1s unable to be written the unit will respond with an error response Note that both a write fields and an error response may be received as a result of a write fields command Attempts to write a field with an invalid value is one way to generate an error response A table of field IDs and valid field values is available in Section 8 1 Scaling Unis co meds fui _ The numberof fields owie 1 fem Jur The fisted Dtowite 5 eoa U The first eld IDs data to write 5 est Jur The second field to write T iea uz The second fld Dsdata pe lr pe ums fei Up TehsfediDbwie
14. 0x3C Read Only Bits Description Default 0x0000 Accelerometer Z Axis self test bit 0 Pass 1 Fail Accelerometer Y Axis self test bit 0 Pass 1 Fail Accelerometer X Axis self test bit 0 Pass 1 Fail Rate Sensor Z Axis self test bit 0 Pass 1 Fail Rate Sensor Y Axis self test bit 0 Pass 1 Fail Rate Sensor X Axis self test bit 0 Pass 1 Fail Self Test Success Failure bit 0 Success 1 Failure s over range bit a 1 indicates one or more sensors have over ranged 5 6 DMU380ZA SPI Register Write Methodology The SPI master configures the DMU380ZA by writing to specific registers However unlike reads writes are performed one byte at a time The specific registers that affect system configuration are listed in Table 24 along with their write addresses Table 24 DMU380ZA Configuration Registers Write Address SELF_TEST 0x35 See Table 25 Initiate self test and Configure Data Ready DATA_READY 0x34 output signal OUTPUT_DATA_RATE 0x37 See Table 26 Sets Output Data Rate ODR and SYSTEM_CLOCK 0x36 internal external system clock Doc 7430 3810 Rev 02 Page 38 DMU380ZA Series User s Manual MEMSIC RS DYNAMIC RANGE See Table 27 Set the rate sensor dynamic range and the LOW PASS FILTER 0x38 digital filter MAG ALIGN See Section 5 7 4 Command to initiate a magnetic alignment The following example highlights how write commands are formed in order to initiate a sensor self test e Select the wri
15. 7430 3810 Rev 02 Page 19 DMU380ZA Series User s Manual MEMSIS gt magnetic field on input direction is called the soft iron effect The AHRS380ZA can actually measure any constant magnetic field that 1s associated with your system and correct for it The AHRS380ZA can also make a correction for some soft iron effects The process of measuring these non ideal effects and correcting for them is called hard iron and soft iron calibration This calibration will help correct for magnetic fields that are fixed with respect to the AHRS380ZA It cannot help for time varying fields or fields created by parts that move with respect to the AHRS380ZA Because time varying fields cannot be compensated selection of a proper installation location 1s important During the calibration procedure the AHRS380ZA makes a series of measurements while the user system is being turned through a complete 360 degree circle A 360 degree rotation gives the AHRS380ZA visibility to hard and soft iron distortion in the horizontal plane Using NAV VIEW a user can see the hard and soft iron effects by selecting the Misalignment option on the Configuration Menu and viewing the magnetic circle during the calibration The AHRS380ZA uses these measurements to model the hard iron and soft iron environment in your system and store these as calibration constants in the EEPROM The status of the AHRS380ZA magnetometer calibration is indicated by the softwareError dataFrror magAlignO
16. AHRS380ZA Advanced Settings In addition to the configurable baud rate packet rate axis orientation and sensor low pass filter settings the AHRS380ZA provides additional advanced settings which are selectable for tailoring the AHRS380ZA to a specific application requirements The AHRS380ZA advanced settings are shown in Table 10 Table 10 AHRS380ZA Series Advanced Settings Baud Rate 38 400 9600 19200 57600 also available baud Packet A1 0 S1 A2 NO N1 also available Type Packet 25 Hz This setting sets the rate at which selected Packet Type packets are output If polled Rate mode is desired then select Quiet If Quiet is selected the VG380ZA will only send measurement packets in response to GP commands Orientation See To configure the axis orientation select the desired measurement for each axes NAV Figure 6 VIEW will show the corresponding image of the AHRS380ZA so it easy to visualize the and mode of operation See section 8 4 Orientation Field settings for the twenty four possible Figure 7 orientation settings The default setting points the connector AFT Filter 20 Hz The low pass filters are set to a default of 20Hz for the accelerometers and 20Hz for the Settings accels angular rate sensors There is one filter setting for all three angular rate sensors There 20 Hz is one filter setting for all three accelerometer sensors The reason for filtering the vd accelerometers is that in many installations the vibrat
17. Com Serial A BIT Field COMM BUS B R oe N A See Section 9 8 Com Serial B BIT Field SENSOR STATUS R x N A See Section 9 15 Sensor Status Field Reserved N A 0x70 to Ox7F 5 2 DMU380ZA SPI Register Read Methodology The DMU380ZA SPI port uses registers to store data such as e Sensor data e Algorithm output data Doc 7430 3810 Rev 02 Page 33 DMU380ZA Series User s Manual MEMSIS gt e Configuration Status information The SPI master accesses information via the SPI bus in one of two ways e Polled Mode e Burst Mode In polled mode the DMU380ZA transfers information from any register back to the master in two or more SPI cycles In Burst Mode the DMU380ZA transfers predefined blocks of data in one contiguous group of nine to twenty SPI cycles 5 21 DMU380ZA SPI Port Polled Mode Read In polled mode data transfer begins when the SPI master sets the chip select line nSS low and clocks a 16 bit word comprised of the register address byte and a zero byte across the MOSI line For example to request the unit s serial number stored in register 0x58 the master sends the command 0x5800 The DMU380ZA returns information from this address across the MISO line during the following 16 clock cycles Subsequent SPI master commands sent to the DMU380ZA consist of either e Sixteen zero bits 0x0000 to complete the read of a single register e The address of another register followed by a zero byte This permits back to back rea
18. Default 0x0004 15 11 Unused 10 Unit self test bit bit reset upon completion of self test 0 Disabled default 1 Enabled Unused 7 3 Unused Data ready enable bit 0 Disabled 1 Enabled default Data ready line polarity 0 Low upon data ready default 1 High upon data read The self test enables the system to test individual sensors by applying a temporary bias to determine if they are responding correctly Once self test completes the self test bit bit 10 1s reset to indicate that the test is finished Results of the self test are store in the status register Ox3C To initiate self test the master sends OxB504 across the SPI bus The data ready bits enable the master to enable or disable the data ready signal provided on pin 7 of the DMU380ZA and to set the data ready signal polarity high or low To enable data ready with a high signal the master sends 0xB406 5 7 2 Output Data Rate Clock Configuration Output data rate ODR and system clock configuration are combined into a single 16 bit register at memory location 0x36 individual bits are assigned according to Table 26 Note these settings apply only to data output via the DMU380ZA SPI port and do not affect the low level UART output port Table 26 Output Data Rate Clock Configuration Register Base Address 0x36 Read Write Description Default 0x0101 sam Dock 7430 3810 Rev 02 Page 40 DMU380ZA Series User s Manual MEMSIZ 8 11 Sy
19. Heading Track Offset Heading Track Offset to use in NAV filter track 0x000C Any update mode Note BAUD rate SF has immediate effect Some output data may be lost Response will be received at new BAUD rate Gyro Filter Setting gt PE 0 2 Continuous Packet Type Field This 1s the packet type that 1s being continually output The supported packet depends on the model number Please refer to Section 7 4 for a complete list of the available packet types Doc 7430 3810 Rev 02 Page 63 DMU380ZA Series User s Manual MEMSIS gt 0 3 Digital Filter Settings These two fields set the digital low pass filter cutoff frequencies See Table 35 Each sensor listed is defined in the default factory orientation Users must consider any additional rotation to their intended orientation Table 35 Digital Filter Settings Filter Setting Ux Uy Uz Rate FilterAccel Ux Uy Uz Accel 8 4 Orientation Field This field defines the rotation from the factory to user axis sets This rotation 1s relative to the default factory orientation for the appropriate DMU380 family model The default factory axis setting for the IMU380ZA 200 orientation field 1s Uy Ux Uz which defines the connector pointing in the Z direction and the X direction going from the connector through the serial number label at the end of the DMU380 The user axis set X Y Z as defined by this field setting is depicted in Figure 18 below Z Uz Yaw
20. ew This command resets the state estimation algorithm without reloading fields from EEPROM All current field values will remain in affect The unit will respond with an algorithm reset response 7 2 3 Algorithm Reset Response Algorithm Reset AR 0x4152 PacketType Length 0x5555 0x4152 lt CRC U2 gt The unit will send this packet in response to an algorithm reset command 7 2 4 Calibrate Command Calibrate WC 0x5743 Packet Type Length Payload 0x5555 0x5743 lt WC payload gt lt CRC U2 gt This command allows the user to perform various calibration tasks with the DMU380ZA Series See the calibration command table below for details The unit will respond immediately with a calibrate response containing the calibrationRequest received or an error response if the command cannot be performed WC Payload Contents Byte Offset Name Format Scaling Units Po calibrationRequest Po po o The requested calibration task Currently magnetic alignment 1s the only function supported by the calibrate command There are two magnetic alignment procedures supported 1 magnetic alignment with automatic yaw tracking termination and magnetic alignment without automatic termination calibrationRequest Description 0x0009 Begin magnetic alignment without automatic termination Rotate vehicle Doc 7430 3810 Rev 02 Page 52 DMU380ZA Series User s Manual MEMSIZ through gt 360 degrees yaw and then s
21. mumFis i fed Dda U2 ThelsfediDsddatowie Write Fields Hesponse Write Fields WF 0x5746 Packet Type Length Payload 0x5555 0x5746 1 numFields 2 WF payload CRC U2 gt The unit will send this packet in response to a write fields command if the command has completed without errors WF Payload Contents Bye Of mmes Ui The number of las writen ed U2 Thefisfeld D writen field1 uu fe The second field ID written Doc 7430 3810 Rev 02 Page 67 DMU380ZA Series User s Manual MEMSIS gt uU Ta de More field IDs written numFields 1 Field U2 Thelastfield ID written 8 8 2 Set Fields Command Set Fields SF 0x5346 Packet Type Length Payload 0x5555 0x5346 1 numFields 4 lt SF payload gt lt CRC U2 gt This command allows the user to set the unit s current configuration SF fields immediately which will then be lost on power down NumFields is the number of words to be set The fieldO fieldl etc are the field IDs that will be written with the fieldOData field Data etc respectively This command can be used to set configuration fields The unit will not set calibration or algorithm fields If at least one field is successfully set the unit will respond with a set fields response containing the field IDs of the successfully set fields If any field 1s unable to be set the unit will respond with an error response Note that both a
22. packet see Section 7 4 1 S1 BURST 0x42 N A Burst Mode Command for UCB scaled sensor 1 data packet see Section 7 4 2 A1 BURST 0x43 N A Burst Mode Command for UCB angle 1 data packet see section 7 4 3 A2 BURST 0x44 N A Burst Mode Command for UCB angle 2 data packet see section 7 4 4 NO BURST 0x45 N A Burst Mode Command for UCB nav 0 data packet see Section 7 4 5 Reserved N A 0x46 to 0x47 X HARD IRON R us 00 Hard iron bias X Axis Y HARD IRON R oa 0 Hard iron bias Y Axis SF SOFT IRON RO oc Jo Soft iron scale factor ANG SOFT IRON RO ue ooo Soft iron angle MAG ALIGN R W 0x50 0x51 N A See Table 29 Magnetic alignment control and status MANUF_CODE R as oo Manufacturing code indicating year and location UNIT_CODE Ro l5 b Unit information code PRODUCT ID R so peo Product identification code SERIAL NUMBER R logs ares era number MASTER STATUS R aa N A See Section 9 2 Master BIT and Status Field HW STATUS R bs N A See Section 9 3 Hardware BIT Field SW MASTER R bs N A See Section 9 9 Software BIT Field SW STATUS R eo N A See Section 9 14 Software Status Field SW ALGO R oe N A See Section 9 10 Software Algorithm BIT Field SW DATA R a N A See Section 9 11 Software Data BIT Field COMM MASTER R oe N A See Section 9 6 Com BIT Field De pos o pos COMM DATA STATUS R e N A See Section 9 13 Com Status Field poa poco por COMM BUS A R aa N A See Section 9 7
23. 9039209550902009 0 928 980 00900 0 0 0 0898 50094 I 1 2 Overview of the DMU380ZA Series Inertial Systems eseeeseeeeee 2 PME i us 4 2k S ocu zm 4 2 1 1 Connector and Mating Connector sse nennen 4 2 1 2 Power Input and Power Input Ground cccccccccccceccceeceeeeeessesseeeeeeeeeees 5 PN MEE OCC EL Tm 5 2 1 4 External GPS Aiding VG380ZA AHRS380ZA and INS380ZA 5 2 1 5 Reserved Factory Use Only vissicissosdecessececuscesdsedeosasssasssendedasstsssacsoedeuieeseaienes 6 2 2 Mechanical Interia E seisen NES 6 r Peon or Oea E terassaoeeceaie 7 3 1 DMU380ZA Series Default Coordinate System eessssseeese 11 SN A e NER EU EEE 12 3 2 IMU380ZA Theory of Operation eeesessssssssseeeeeeeeennn nnne 12 3 2 IMU380ZA Advanced Settings esses 13 3 2 2 IMUSSOZA Built In T68L iuicceseicoeciosvesa scudo iii repu eUU o s pn Un bui E cre Soo api pensada 14 3 3 VG380ZA Theory of Operation eeeeeessessssseseeeeeeeeenee nnne nennen eene 14 dd VG380ZA Advanced Settings sccnssesicctsdavecirssosacsusensadenasanacsbitenyeseseressusuecades 16 4 3 2 VG380ZA Built In 680 secerni eea ai 17 3 4 AHRS380ZA Theory of Operation eeessssssssseeeeeeennennn nnne 18 3 4 1 AHRS380ZA Magnetometer Calibration and Alignment 19 3 4 2 AHRS3
24. LSB contains BIT information and the MSB contains status information There are four intermediate signals that are used to determine when masterFail and the hardware BIT signal are asserted These signals are controlled by various systems checks in software that are classified into three categories hardware communication and software Instantaneous soft failures in each of these four categories will trigger these intermediate signals but will not trigger the masterFail until the persistency conditions are met There are four intermediate signals that are used to determine when the masterStatus flag is asserted hardwareStatus sensorStatus comStatus and softwareStatus masterStatus is the logical OR of these intermediate signals Each of these intermediate signals has a separate field with individual indication flags Each of these indication flags can be enabled or disabled by the user Any enabled indication flag will trigger the associated intermediate signal and masterStatus flag Table 41 DMU380 BIT Status Field BiTstatusField Bits Meaning Category maseral 0 J O normal 1 fatal error has occurred BIT Reseved ea ENA masterStatus 0 nominal 1 hardware sensor com or Status software alert FhadwaeSmus o 0 nominal t programmablelen Sets Rere foe Qua o Doc 7430 3810 Rev 02 Page 73 DMU380ZA Series User s Manual MEMSIS gt 9 3 hardwareBIT Field The hardw
25. REMARKS does not do boundary checking please do this first HK KK KK kk kCk kk k ck kk ck ck k kc k ck k ck ck kk k ck k kc k ck kk ck kk ck ck k kc k ck kc k ck kk ck ck kk ck kk ck ck k kc k ck k ck ck kk kck k kck kk kk unsigned short peekWord QUEUE TYPE queue ptr unsigned int index 4 unsigned short word firstIndex secondIndex firstIndex queue ptr gt front index MAXQUEUE secondIndex queue ptr gt front index 1 MAXQUEUE word queue ptr entry firstliIndex lt lt 8 amp OxFEOO word 0x00FF amp queue ptr entry secondIndex return word f RKCKCKCK A kk KKK KK KK Kk KK Ck KK kk KK Kk KC kk Ck Ck kk kCk ck ck ck kck ck k kc k ck k ck ck k ck ck ck k kk kk FUNCTION Pop discard item s from queue ARGUMENTS queue ptr is pointer to the queue i numToPop is number of items to discard RETURNS return the number of items discarded Doc 7430 3810 Rev 02 Page 100 DMU380ZA Series User s Manual MEMSIC HK KK KK k ck k kk kk k ck kk ck ck k kc k ck k ck ck kk ck ck k kc k ck kc k ck k kc k ck k kc k ck kc k ck k kc k ck k kc k kk ck ck k kc k ck k ck ck kckckck k kck kk kk f int Pop QUEUE TYPE queue ptr int numToPop int 1 0 char tempchar for 1 0 i numToPop i if DeleteQueue amp tempchar queue ptr break return i f RKCKCKCK kk KK KKK KKK KK KK Kk KK kk KK kk KK kk OK kCkCkck ck kck ck k ck ck ck k ck ck k ck ck ck k ck ck k kc k ck k kk k FUNCTI
26. Radians Yaw angle true north xRateCorrected 12 7 pi 2 16 rad s X angular rate corrected yRateCorrected 12 T pi 2 16 rad s Y angular rate corrected 10 zRateCorrected 12 7 pi 2416 rad s Z angular rate corrected 1260 2 16 sec 512 26 North velocity fete E 51226 ms East velocity HL 512 46 mls Down velocity r M 2 pi 2 32 Radians GPS Longitude 360 2 32 latitudeGPS 2 pi 2 32 Radians GPS Latitude 360 2 32 26 altitudeGPS 2 2M4 2M6 m GPS altitude 100 16284 GPSITOW truncated GPS ITOW lower 2 bytes 30 BlTstatus H ls de 3 Master BIT and Status 7 4 6 Nav Data Packet 1 Default INS Data Nav Data N1 0x4E31 Packet Type Length Payload 0x5555 0x4E31 N1 payload CRC U2 gt This packet contains navigation data and selected sensor data scaled in most cases to a signed 2 16 2 s complement number Data involving angular measurements include the factor pi in the scaling and can be interpreted in either radians or degrees Angles scaled to a range of p1 p1 or 180 deg to 180 deg Angular rates scaled to range of 3 5 pi pi or 630 deg sec to 630 deg sec Accelerometers scaled to a range of 10 10 g Temperature scaled to a range of 100 100 C Velocities are scaled to a range of 256 256 m s Altitude is scaled to a range of 100 16284 m using a shifted 2 s complement representation Longitude and latitude are scaled to a ran
27. V 1 4Sample Rate C 1 10 Sample Rate Test Duration v 1 100 Sample Rate Days o Hours l0 Samples Second 1 Minutes o ES Seconds Sample 4 Seconds 10 H Cancel OK Figure 20 Log to File Dialog Screen Select the Browse box to enter the file name and location that you wish to save your data to Select the type of data you wish to record Engineering Data records the converted values provided from the system in engineering units Hex Data Doc 7430 3810 Rev 02 Page 82 DMU380ZA Series User s Manual MEMSIC gt provides the raw hex values separated into columns displaying the value and the Raw Packets will simply record the raw hex strings as they are sent from the unit 5 Users can also select a predetermined Test Duration from the menu Using the arrows simply select the duration of your data recording 6 Logging Rate can also be adjusted using the features on the right side of the menu 7 Once you have completed the customization of your data recording you will be returned to the main screen where you can start the recording process using the button at the top of the page or select Start Logging from the File menu Stopping the data recording can be accomplished using the Bl button and the recording can also be paused using the Il button Data Playback In addition to data recording NAV VIEW allows the user to replay saved data that has been stored i
28. and display the serial number and firmware version if it is connected 2 If NAV VIEW does not connect check that you have the correct COM port selected You will find this under the Setup menu Select the appropriate COM port and allow the unit to automatically match the baud rate by leaving the Auto match baud rate selection marked to go If the status indicator doesn t say connected and 1s red check the connections between the DMU380ZA Series product and the computer check the power supply and verify that the COM port is not occupied by another device 4 Under the View menu you have several choices of data presentation Graph display 1s the default setting and will provide a real time graph of all the DMU380ZA Series data The remaining choices will be discussed in the following pages Data Recording NAV VIEW allows the user to log data to a text file txt using the simple interface at the top of the screen Customers can now tailor the type of data rate of logging and can even establish predetermined recording lengths To begin logging data follow the steps below See Figure 20 l Locate the icon at the top of the page or select Log to File from the File drop down menu 2 Thefollowing menu will appear Log to File Log File Browse Log Type Logging Rate Enginerring Data Fractional Rate Full Sample Rate Hex Data C 4 2 Sample Rate f Raw Packets Hex
29. detailed BIT and status information The full BIT Status details are described in Section 9 of this manual T0 Payload Contents O BiTstatus U2 f f Master BIT and Status Field 2 hardwareBIT U2 f Hardware BIT Field 4 hardwarePowerBIT_ U2 f Hardware Power BIT Field hardwareEnvironmentalBIT U2 oo Hardware Environmental BIT Field U2 i communication BIT Field 2 comSerialABIT U Communication Serial A BIT Field comSerialBBIT epo po Communication Serial B BIT Field 10 softwareBIT Software BIT Field softwareAlgorithmBIT U2 Software Algorithm BIT Field U2 CEN um Software Data BIT Fid Hardware Status Fid Communication Staus Field Software Status Field Sensor Status Field softwareStatus 7 4 Output Packets Polled or Continuous 7 4 1 Scaled Sensor Data Packet 0 Scaled Sensor Data S0 0x5330 Packet Type Length Payload 0x5555 0x5330 S0 payload CRC U2 gt This packet contains scaled sensor data The scaled sensor data is fixed point 2 bytes per sensor MSB first for 13 sensors in the following order accels x y z gyros x y z mags x y z temps x y z board Data involving angular measurements include the factor pi in the scaling and can be interpreted in either radians or degrees Angular rates scaled to range of 3 5 pi pi or 630 deg sec to 630 deg sec Doc 7430 3810 Rev 02 Page 55 DMU380ZA Series User s Man
30. ey Doc 7430 3810 Rev 02 Page 45 DMU380ZA Series User s Manual MEMSIS gt 6 DMU380 UART Port Interface Definition The DMU380ZA Series contains a number of different products which have different measurement capabilities Depending on the model you purchased various commands and output modes are supported However all models support a common packet structure that includes both command or input data packets data sent to the DMU380ZA Series and measurement output or response packet formats data sent from the DMU380ZA Series This section of the manual explains these packet formats as well as the supported commands NAV VIEW also features a number of tools that can help a user understand the packet types available and the information contained within the packets This section of the manual assumes that the user 1s familiar with ANSI C programming language and data type conventions For an example of the code required to parse input data packets please see refer to Appendix C For qualified commercial OEM users a source code license of NAV VIEW can be made available under certain conditions Please contact your MEMSIC representative for more information 6 1 General Settings The serial port settings are RS232 with 1 start bit 8 data bits no parity bit 1 stop bit and no flow control Standard baud rates supported are 9600 19200 38400 and 57600 Common definitions include e A word is defined to be 2 bytes or 16 bits e Al
31. may be different from the value stored in the EEPROM can also be accessed using the GF command All of these fields can also be modified immediately for the duration of the current power cycle using the SF command The unit will always power up in the configuration stored in the EEPROM Configuration fields can only be set or written with valid data from Table 34 below Table 34 Configuration Fields configuration fields field ID Valid Values description Packet rate divider 0x0001 0 1 2 5 10 20 25 50 quiet 100Hz 50Hz 25Hz 20Hz 10Hz 5Hz 2Hz Unit BAUD rate 0x0002 0 1 2 3 9600 19200 38400 57600 Not all output packets available for all products Continuous packet type 0x0003 Any output packet type See detailed product descriptions C o 7142 65535 5Hz 3571 7141 10Hz 1530 3570 20Hz Sets low pass cutoff for rate sensors Cutoff 0 1529 50 Hz Frequency choices are 5 10 20 and 50Hz 7142 65535 5Hz 3571 7141 10Hz 1530 3570 20Hz Sets low pass cutoff for accelerometers Cutoff Accelerometer Filter Setting 0x0006 0 1529 50 Hz Frequency choices are 5 10 20 and 50Hz Determine forward rightward and downward Orientation 0x0007 See below facing sides Free Integrate Use Mags Use GPS Stationary User Behavior Switches 0x0008 Any Yaw Lock X Hard Iron Bias 0x0009 Any I2 scaled from 1 1 Y Hard Iron Bias 0x000 I2 scaled from 1 1 Soft Iron Scale Ratio 0x000 U2 scaled from 0 2
32. or on a polled basis from the SPI port or the UART port The SPI port outputs data via registers and the user can perform polled reads of each register or a block burst read of a set of predefined registers Output data over the SPI port can be synchronized to an external 1 KHz pulse Alternatively users can input a 1 PPS signal from an external GPS receiver when providing external GPS data over the secondary UART2 port The complete SPI interface 1s defined in Section 4 The UART port outputs data packets are asynchronous and defined in Sections 5 7 As shown in the block diagram Figure 3 the INS380ZA and AHRS380ZA include an internal 3 axis magnetometer Dock 7430 3810 Rev 02 Page 8 DMU380ZA Series User s Manual MEMSIC X Y Z High Speed Gyros X Y Z Accelerometers Temperature Sensor 6 DOF Sensor Cluster X Y Z Magnetometers System Digital Outputs and Inputs UART1 Pins 3 4 or SPI Pins 3 6 Sampling amp B m MEMSIC Serial Protocol UART1 SPI Registers SPI Sensor mX Y Z Acceleration Compensation E l Filtering m Roll Pitch Yaw Rate E m X Y Z Magnetic Fields INS AHRS only E Navigation amp m Attitude a m UART2 External GPS Input Kal Fil alman Filter VG AHRS INS SPI Com Sync 1 KHz Pulse External GPS 1 PPS Input Pin 2 Figure 3 DMU380ZA Series Hardware Block Diagram Figure 4 shows the software block diagram The 6 DOF inertial sen sor cluster data
33. system Pin 2 should be used for the 1PPS input signal to force synchronization of sensor data collection to a 1Hz rising edge signal The signal must maintain 0 0 0 2 V zero logic and 3 0 5 0 volts high logic and stay within 100ms of the internal system 1 second timing Sending this signal to the system will align the sensor data collection and algorithm processing to its rising edge and 10ms boundaries thereafter When the system is synchronized to I PPS the hardwareStatus 2 unlocked1 PPS flag will be zero otherwise it will be one 2 1 4 3 SPI Com Synchronization Input If the user does not have I PPS available from an external GPS receiver then Pin 2 can be used as a sync pulse to force synchronization of sensor data collection to a 1 KHz rising edge signal for output over the SPI port 2 1 4 3 External GPS Receiver Antenna Connection The external GPS receiver needs to receive signals from as many satellites as possible A GPS receiver doesn t work properly in narrow streets and underground parking lots or if objects or human beings cover the antenna Poor visibility may result in position drift or a prolonged Time To First Fix TTFF A good sky visibility is therefore a prerequisite Even the best receiver can t make up for signal loss due to a poor antenna in band jamming or a poor RF cable Placing the antenna on a 4 inch or larger ground plane is highly recommended gt IMPORTANT Place the antenna with optimal sky visibility a
34. tables Coupled to the 6 DOF MEMS inertial sensor cluster is a high performance microprocessor that utilizes the inertial sensor measurements to accurately compute navigation information including attitude heading and linear velocity thru dynamic maneuvers actual measurements are a function of the DMU380ZA Series product as shown in Table 2 In addition the processor makes use of internal magnetic sensor and external GPS data to aid the performance of the inertial algorithms and help correct long term drift and estimate errors from the inertial sensors and computations The navigation algorithm utilizes a multi state configurable Extended Kalman Filter EKF to correct for drift errors and estimate sensor bias values Another unique feature of the DMU380ZA Series is the extensive field configurability of the units This field configurability allows the DMU380ZA Series of Inertial Systems to satisfy a wide range of applications and performance requirements with a single mass produced hardware platform The basic configurability includes parameters such as baud rate UART clock speed SPI packet type and update rate and the advanced configurability includes the defining of custom axes and how the sensor feedback is utilized in the Kalman filter during the navigation process The DMU380ZA Series is packaged in a light weight rugged unsealed metal enclosure that is designed for cost sensitive commercial and OEM applications The DMU380 can b
35. the signal 1 e can wash out the signals containing the dynamics of a target Treat the filter settings with caution Dock 7430 3810 Rev 02 Page 13 DMU380ZA Series User s Manual MEMSIS gt 3 2 2 IMU380ZA Built In Test The IMU380ZA Built In Test capability allows users of the IMU380ZA to monitor health diagnostic and system status information of the unit in real time The Built In Test information consists of a BIT word 2 bytes transmitted in every measurement packet In addition there 1s a diagnostic packet TO that can be requested via the Get Packet GP command which contains a complete set of status for each hardware and software subsystem in the IMU380ZA See Sections 6 8 for details on the TO packet The BIT word which is contained within each measurement packet is detailed below The LSB Least Significant Bit 1s the Error byte and the MSB Most Significant Bit is a Status byte with programmable alerts Internal health and status are monitored and communicated in both hardware and software The ultimate indication of a fatal problem is the masterFail flag The masterStatus flag is a configurable indication that can be modified by the user This flag is asserted as a result of any asserted alert signals which have been enabled See Advanced BIT Section 9 for details regarding the configuration of the masterStatus flags Table 7 shows the BIT definition and default settings for BIT programmable alerts in
36. the IMU380ZA Table 7 IMU380ZA Default BIT Status Definition Cansat is Mann o maseta Jo Oemmai Gaemrsommd for Rew 8 Qua O mswSms le O remmiicAst Sensor GverRange Seus termes o Dmhed Sd Sts ww O quis qua o The IMU380ZA also allows a user to configure the Status byte within the BIT message To configure the word select the BIT Configuration tab from the Unit Configuration menu The dialog box allows selection of which status types to enable hardware software sensor and comm In the case of the IMU380ZA which has fewer features and options than other DMU380ZA Series products the only meaningful parameter is sensor over range It is recommended that users leave the default configuration which is sensorStatus enabled and flag on sensor over range The over range only applies to the rotational rate sensors Because instantaneous acceleration levels due to vibration can exceed the accelerometer sensor range in many applications none of the DMU380ZA Series products trigger over range on accelerometer readings 3 3 VG380ZA Theory of Operation The VG380ZA supports all of the features and operating modes of the IMU380ZA and it includes additional internal software running on the processor for the computation of dynamic roll and pitch The product name VG380ZA stands for Vertical Gyro 380 and Doc 7430 3810 Rev 02 Page 14 DMU380ZA Series User s Manual MEMSIZ it is indicative of the vertical gyro func
37. the requested information concurrently across MISO to the master To complete the data transfer the final read command must be followed by an additional 16 clock cycles to transfer the last 16 bits of data In this example the master requests data from four separate registers x axis rate 0x0400 y axis rate 0x0600 z axis acceleration OxOEOO and system status 0x3C00 The transfer of 0x0000 across MOSI completes the read by returning the status data via the MISO line nSS CLK MOSI 0x0400 0x0600 0x0E00 073000 X 0x0000 Figure 10 Multiple Register Read via Polled Mode 5 2 2 DMUS80ZA SPI Port Burst Mode Read In burst mode the DMU380ZA returns predefined blocks of data in single groups referred to as data packets without the need to send multiple read commands These groups vary from eight to nineteen words in length depending on the packet selected Table 19 lists the data packets available for the DMU380ZA The data packets are described in more detail including data ordering and conversion factor information in Section 7 4 Table 19 DMU380ZA Burst Mode Data Packets Data Packet Register Number of Pertinent Availability EN a bit Words E Standard OE 822 2 2 All Allsystems Scaled Sensor 0 0x41 1 4 1 All systems except IMU380ZA 200 and VG380ZA Burst Read of Standard Data Packet The standard data packet comprises data from eight predefined
38. this point the hard iron and soft iron estimates are written to registers 0x48 through 0x4F and saved to the EEPROM The Kalman filter algorithm is reset to stabilization mode It remains in this state for five seconds to allow the user to bring the system to rest while the initialization process completes Conversion factors from values in the hard and soft iron registers 0x48 through Ox4E to decimal equivalents are provided in Table 30 Table 30 DMU380 Magnetic Alignment Parameters Register ame Mee mm m ue X Axis Hard lron Bias Signed Integer 20 26 10 10 Y Axis Hard lron Bias oigned Integer 20 216 10 10 Soft Iron Scale Ratio Unsigned Integer 2 2416 0 2 Soft lron Angle Signed Integer 2 pi 2 5 1 ipi Radans 5 8 Suggested Operation The following operational procedure and timing specifications should be adhered to while communicating with the DMU380 via SPI to ensure proper system operation These points are further highlighted later in this section Startup Timing The following timing applies at system startup Figure 15 e During system setup the DMU380 should be held in reset nRST line held low until the SPI master is configured and the system is ready to begin communications with the DMU380 e After releasing the reset line the DMU380 requires 100 msec tsystem Delay before the system is ready for use Dock 7430 3810 Rev 02 Page 43 DMU380ZA Series User s Manual MEMSIS gt e Data shoul
39. to configure the Status byte within the BIT message To configure the word select the BIT Configuration tab from the Unit Configuration menu The dialog box allows selection of which status types to enable hardware software sensor and comm Like the IMU VG and AHRS380ZA MEMSIC recommends for the vast majority of users that the default Status byte for the INS380ZA is sufficient For users who wish to have additional visibility or alerts relative to the GPS sensor status or algorithm status they can configure additional triggers for both the softwareStatus and hardwareStatus See Section 9 of the user s manual for a description of all the BIT fields hardwareStatus comStatus softwareStatus Doc 7430 3810 Rev 02 Page 27 DMU380ZA Series User s Manual MEMSIC 4 Application Guide 4 1 Introduction This section provides recommended advanced settings for tailoring the DMU380ZA Series of inertial systems to different types of application and platform requirements 4 2 Fixed Wing Aircraft A fixed wing aircraft is a heavier than air craft where movement of the wings in relation to the aircraft is not used to generate lift The term is used to distinguish from rotary wing aircraft where the movement of the wing surfaces relative to the aircraft generates lift The fixed wing aircraft can range in size from the smallest experimental plane to the largest commercial jet The dynamic characteristics of the fixed wing aircraft depends
40. upon types of aircraft 1 g glider propeller aircraft and jet aircraft and mission phases 1 e launch landing and maneuver In order to meet application requirements users must dial in proper advanced settings so that the DMU380ZA Series can provide the best possible solution under given dynamic conditions For example Table 14 provides the recommended advanced settings for four different dynamic conditions Table 14 Recommended Advanced Settings for Fixed Wing Aircraft Recommended AHRS380ZA or INS380ZA Product Dynamic Condition d Pre launch or known Launch Normal g straight and level un Dynamics High Dynamics accelerated flight Default A cutoff frequency of filters may be varied depending on the fastest dynamic mode of the aircraft For example the conventional aircraft has five dynamic modes short period phugoid spiral dutch roll and roll and the fastest one is the roll mode The natural frequency of this mode is around 6 8 radian sec or about 2 Hz in most cases Therefore the recommended filter setting would not reject desired frequency components or dynamic modes that one wants to capture However the larger the bandwidth or cutoff frequency is the noisier the corresponding signal is which may result in the performance degradation If the aircraft is operated under severe vibrations also the recommended filter setting may need to be further reduced in order to reject the frequency components caused by the
41. using the GP Get Packet command In addition to the angle mode packets of the AHRS380ZA and scaled sensor packets of the IMU380ZA the INS380ZA has additional output measurement packets including the default N1 Navigation Packet which outputs the Latitude Longitude Altitude X Y Z velocities accelerations and roll angle pitch angle yaw angle and digital IMU data See Sections 6 and 7 of the manual for full packet descriptions All data is also available on the SPI output port registers Please refer to section 5 for a complete description of the SPI port functionality gt IMPORTANT For proper operation the INS380ZA relies on magnetic field readings from its internal 3 axis magnetometer The INS380ZA must be installed correctly and calibrated for hard Doc 7430 3810 Rev 02 Page 24 DMU380ZA Series User s Manual MEMSIC iron and soft iron effects to avoid any system performance degradation See section 3 4 1 for information and tips regarding installation and calibration and why magnetic calibration is necessary Please review this section of the manual before proceeding to use the INS380ZA gt IMPORTANT For optimal performance the INS380ZA utilizes GPS readings from an external GPS receiver The GPS receiver requires proper antennae installation for operation See section 2 1 4 for information and tips regarding antenna installation 3 5 1 INS380ZA Magnetometer Calibration and Alignment The INS380ZA requires the th
42. will take effect immediately by modifying internal RAM and are lost on a power cycle 6 3 3 Payload Length The payload length is always a one byte unsigned character with a range of 0 255 The payload length byte is the length in bytes of the variable length payload portion of the packet ONLY and does not include the CRC 6 3 4 Payload The payload 1s of variable length based on the packet type 6 3 5 16 bit CRC CCITT Packets end with a 16 bit CRC CCITT calculated on the entire packet excluding the 0x5555 header and the CRC field itself A discussion of the 16 bit CRC CCITT and sample code for implementing the computation of the CRC is included at the end of this document This 16 bit CRC standard is maintained by the International Telecommunication Union ITU The highlights are Width 16 bits Polynomial 0x1021 Initial value OXFFFF No XOR performed on the final value See Appendix C for sample code that implements the 16 bit CRC algorithm 6 3 6 Messaging Overview Table 33 summarizes the messages available by DMU380ZA Series model Packet types are assigned mostly using the ASCII mnemonics defined above and are indicated in the summary table below and in the detailed sections for each command The payload byte length is often related to other data elements in the packet as defined in the table below The referenced variables are defined in the detailed sections following Output messages are sent from the DMU380ZA Series
43. 2 Locate the NAV VIEW folder Double click on the setup exe file 3 Follow the setup wizard instructions You will install NAV VIEW and NET 2 0 framework Connections The DMU380ZA Series Inertial Systems products are shipped with a cable to connect the DMU380ZA Series to a PC Serial port 1 Connect the 9 pin micro DB connector end of the digital signal cable to the port on the DMU380ZA Series product 2 Connect the 9 pin sub DB end of the cable marked to the serial port of your computer 3 The additional black and red wires on the cable connect power to the DMU380ZA Series product Match red to power and black to ground The input voltage can range from 9 32 VDC with a maximum current draw of 350 mA 4 Allow at least 60 seconds after power up for the DMU380ZA Series product to initialize The DMU380ZA Series needs to be held motionless during this period N WARNING Do not reverse the power leads Reversing the power leads to the DMU380ZA Series can damage the unit although there is reverse power protection MEMSIC is not responsible for resulting damage to the unit should the reverse voltage protection electronics fail Dock 7430 3810 Rev 02 Page 81 DMU380ZA Series User s Manual MEMSIS gt Setting up NAV VIEW With the DMU380ZA Series product powered up and connected to your PC serial port open the NAV VIEW software application 1 NAV VIEW should automatically detect the DMU380ZA Series product
44. 2 16 sec 22 xwe 02 20246 g X accelerometer 4 Accel 0 202M6 g Yaccelerometer 16 zacel 2 2026 g Z accelerometer 26 timel TOW U4 1 ms DMU ITOW sync to GPS Bisous U2 Master BIT and Status 7 44 Angle Data Packet 2 Default VG Data Angle Data A2 0x4132 Packet Type Length Payload 0x5555 0x4132 A2 payload CRC U2 gt This packet contains angle data and selected sensor data scaled in most cases to a signed 2 16 2 s complement number Data involving angular measurements include the factor pi in the scaling and can be interpreted in either radians or degrees Angles scaled to a range of p1 p1 or 180 deg to 180 deg Angular rates scaled to range of 3 5 pi pi or 630 deg sec to 630 deg sec Accelerometers scaled to a range of 10 10 g Temperature scaled to a range of 100 100 C Doc 7430 3810 Rev 02 Page 58 DMU380ZA Series User s Manual MEMSIC gt A2 Payload Contents Byte Offset Name rollAngle 2 pi 2 16 Radians Roll angle 3607 2 16 pitchAngle 2 pi 2 16 Radians Pitch angle yawAngleTrue 2 pi 2 16 Radians Yaw angle free yRateCorrected T pi 2 16 rad s Y angular rate corrected 1260 2 16 sec 7 pi 2 16 rad s Z angular rate corrected 1260 2 16 sec 2026 g X accelerometer 200M6 g Yacoleomee d2 202M6 g Za
45. 5 shows the definition of the bit mask for configuring the status signals Doc 7430 3810 Rev 02 Page 77 DMU380ZA Series User s Manual MEMSIS gt Table 55 DMU380 Master Status Byte Configuration Fields configuration fields field ID Valid Values Description hardwareStatusEnable 0x0010 Bit mask of enabled hardware status signals comStatusEnable Bit mask of enabled communication status 0x0011 Any signals softwareStatusEnable 0x0012 Bit mask of enabled software status signals sensorStatusEnable 0x0013 Bit mask of enabled sensor status signals 9 16 1 hardwareStatusEnable Field This field is a bit mask of the hardwareStatus field see BIT and status definitions This field allows the user to determine which low level hardwareStatus field signals will flag the hardwareStatus and masterStatus flags in the BITstatus field Any asserted bits in this field imply that the corresponding hardwareStatus field signal if asserted will cause the hardwareStatus and masterStatus flags to be asserted in the BITstatus field 9 16 2 comStatusEnable Field This field is a bit mask of the comStatus field see BIT and status definitions This field allows the user to determine which low level comStatus field signals will flag the comStatus and masterStatus flags in the BITstatus field Any asserted bits in this field imply that the corresponding comStatus field signal if asserted will cause the comStatus and masterStatus flags to be asserted in the
46. 555 4750 02 4944 233d 5555 4746 07 0300010003071c 49f9 5555 4750 02 5652 4287 5555 504b 00 Jef4 5555 4750 02 4944 233d 5555 4746 07 0300010003071c 49f9 5555 4750 02 5652 4287 ffdsffba0002000000020000ff2Z21ff5c01ae0000000000000000000000000000 ffdsfftba000200000002 fffffzZ1ff5c01ae0000000000000000000000000000 fftdsffba000200000001ffffffZ1ff5c0lae0000000000000000000000000000 ffdsfftba000200000001ffffffzZ1ff5c01ae0000000000000000000000000000 fftdsffba000200000001ffffffzZ1ff5c0lae0000000000000000000000000000 ffdsffba000200000001ffffffzZ1ff5c01ae0000000000000000000000000000 ffdsfftba000200000001ffffffZ2ff5c01ae0000000000000000000000000000 ffdSsffba000200000000ffffffZ2ff5c01ae0000000000000000000000000000 fftdsffba000200000000ffffffZ2ff5c01ae0000000000000000000000000000 ffdsfftbb000200000000fffeffZ2ff5c01ae0000000000000000000000000000 fftdsftbb000100000000fffeffZ2ff5c01ae0000000000000000000000000000 ffdsftbb000100000000fffeffZ2ff5c01ae0000000000000000000000000000 fftdsffba000100000000ffffffZ2ff5c01ae0000000000000000000000000000 ffd7ffba000100000000fffeff22ff5c01ae0000000000000000000000000000 ffd7fftba000100000000ffffffZ2ff5c01ae0000000000000000000000000000 Figure 21 Raw Data Console Horizon and Compass View If the DMU380ZA Series product you have connected is capable of providing heading and angle information see Table 2 NAV VIEW can provide a compass and a simulated artificial horizon view To activate these views simply select Horizon Vie
47. 80ZA and AHRS380ZA The INS380ZA builds on the capabilities of the IMU380ZA VG380ZA and AHRS380ZA Customers who want product configuration tips for operating the DMU380ZA Series Inertial Systems in a wide range of applications fixed wing rotary wing unmanned vehicles land vehicles marine vessels and more should review the part of Section 4 that is relevant to your application Note INS and AHRS DMU380ZA Series units are preconfigured for airborne applications with normal dynamics VG380ZA Series units are preconfigured for land applications with automotive testing dynamics All DMU380ZA Series products allow for complete flexibility in configuration by the user Customers designing the software interface to the DMU380ZA series products SPI Port should review Section 5 Customers designing the software interface to the DMU380ZA series products UART Port should review Sections 6 9 Page 1 DMU380ZA Series User s Manual MEMSIC gt 1 2 Overview of the DMU380ZA Series Inertial Systems This manual provides a comprehensive introduction to the use of MEMSIC s DMU380ZA Series Inertial System products listed in Table 2 This manual is intended to be used as a detailed technical reference and operating guide MEMSIC s DMU380ZA Series products combine the latest in high performance commercial MEMS Micro electromechanical Systems sensors and digital signal processing techniques to provide a small cost effective alternative to ex
48. 80ZA and it includes additional capability of interfacing with an external GPS receiver and associated software running on the processor for the computation of navigation information as well as orientation information The product name INS380ZA stands for Inertial Navigation System 380 and it is indicative of the navigation reference functionality that the INS380ZA provides by outputting inertially aided navigation information Latitude Longitude and Altitude inertially aided 3 axis velocity information as well as heading roll and pitch measurements in addition to digital IMU data At a fixed 100Hz rate the INS380ZA continuously maintains the digital IMU data the dynamic roll pitch and heading data as well as the navigation data As shown in the software block diagram in Figure 4 after the Sensor Calibration block the IMU data is passed into an Integration to Orientation block The Integration to Orientation block integrates body frame sensed angular rate to orientation at a fixed 100 times per second within all of the DMU380ZA Series products except IMU380ZA For improved accuracy and to avoid singularities when dealing with the cosine rotation matrix a quaternion formulation is used in the algorithm to provide attitude propagation Doc 7430 3810 Rev 02 Page 23 DMU380ZA Series User s Manual MEMSIS gt Following the integration to orientation block the body frame accelerometer signals are rotated into the NED level
49. 80ZA Advanced Settings sse 24 3 4 3 AHRS380ZA Built In Test ccccccccccssssssesssnsnnnneeeeceeeeceeeesesssseeeeees 22 3 5 INS380ZA Theory of Operation eeeeeeessssssseeeeeeeeeenene nnn nnne nennen 23 3 5 1 INS380ZA Magnetometer Calibration and Alignment 25 3 5 2 INS380ZA Advanced Settings essere 25 DO MEME Do PW Buln ES mE 26 Ay Applicaton CHUIGC NEN T m 28 Ar aodo CM LM RR ETT 28 42 NRC WIE AT seriamente puse a IU Use Mun ED RD ER NUM p OE REIR 28 4 95 lt 6 0 kc 8 RR eee eT oe een Emm IMMANE eet et eer eer eer Te 29 a MES b uicit 20 AS AQUINO RERO m vO em 30 5 DMU380ZA SPI Port Interface Definition eeeeeeeeeseeseeeeeeeennn 32 Doc 7430 3810 Rev 02 Page i DMU380ZA Series User s Manual MEMSIS gt 5 1 DMUSSOZA Register c 32 5 2 DMU380ZA SPI Register Read Methodology eee 33 5 2 1 DMU380ZA SPI Port Polled Mode Read csse 34 5 2 2 DMU380ZA SPI Port Burst Mode Read esee 35 So OUNCE Data IRE CNET TEM 37 Sb SACI 1G 0 aces sai pon ac asa Ene ea ua dia on ion SOU assa aces 37 55 Diagnostic Status RePISIGE oom quieran na eraan Ea dada Ea E sauna 38 5 6 DMU380ZA SPI Register Write Methodology eee 38 do MC On UE AO RC S RIT 40 SMS MEE IE BEIC GUTEN TC asd E 40 5 7 2 Output Data Rate Clock Configuration
50. A Register Map N Z Axis Rate Sensor Output X Axis Accelerometer Output Y Axis Accelerometer Output Z Axis Accelerometer Output N A N A X Axis Magnetometer Output N A Y Axis Magnetometer Output Z Axis Magnetometer Output N A Rate sensor temperature Board temperature Ox1A to 0x33 panes a See Table 25 Initiate Self Test Configure Data Ready 0x35 0x34 0x04 output signal IA R W R W See Table 26 Set Output Data Rate ODR Select the R W 0x37 0x36 0x01 system clock internal external R W See Table 27 Set rate sensor dynamic range SPI only RS_DYNAMIC_RANGE Register and data packet availability is based on the features of the DMU380ZA see Table 2 Register reads are performed 2 bytes at a time while writes are a single byte in length In operation the SELF TEST DATA READY register should be read together starting at register 0x34 This applies to other shared registers as well f an external sync pulse is applied then the system cannot return to internal timing without resetting the system and removing the sync signal Doc 7430 3810 Rev 02 Page 32 DMU380ZA Series User s Manual MEMSIC LOW PASS FILTER R W 0x39 0x38 0x06 select digital filter Reserved N A Ox3A to 0x3B STATUS R o N A See Table 23 Diagnostic register STNDRD BURST RO pae N A o to perform a burst read of the standard data Reserved RO xy to 0x40 NEN S0 BURST 0x41 N A Burst Mode Command for UCB scaled sensor 0 data
51. BIT Configuration tab from the Unit Configuration menu The dialog box allows selection of which status types to enable hardware software sensor and comm Like the IMU380ZA MEMSIC recommends for the vast majority of users that the default Status byte for the VG380ZA is sufficient For users who wish to have additional visibility to when the VG380ZA EFK algorithm estimates that the VG380ZA is turning about its Z or Yaw axis the softwareStatus bit can be configured to go high during a turn In other words the turnSwitch will turn on the softwareStatus bit In the VG380ZA the turnSwitch is by default set at 10 0 deg sec about the z axis 34 AHRS380ZA Theory of Operation The AHRS380ZA supports all of the features and operating modes of the IMU380ZA and VG380ZA and it includes an additional internal 3 axis magnetometer and associated software running on the processor for the computation of dynamic heading as well as dynamic roll and pitch The product name AHRS380ZA stands for Attitude Heading Reference System 380 and it is indicative of the attitude and heading reference functionality that the AHRS380ZA replicates by providing dynamic heading roll and pitch measurements in addition to the VG and IMU data The dynamic heading measurement is stabilized using the 3 axis magnetometer as a magnetic north reference As in the VG380ZA the dynamic roll and pitch measurements are stabilized using the accelerometers as a long term gravity referen
52. BITstatus field 9 16 3 softwareStatusEnable Field This field is a bit mask of the softwareStatus field see BIT and status definitions This field allows the user to determine which low level softwareStatus field signals will flag the softwareStatus and masterStatus flags in the BITstatus field Any asserted bits in this field imply that the corresponding softwareStatus field signal if asserted will cause the softwareStatus and masterStatus flags to be asserted in the BITstatus field 9 16 4 sensorStatusEnable Field This field is a bit mask of the sensorStatus field see BIT and status definitions This field allows the user to determine which low level sensorStatus field signals will flag the sensorStatus and masterStatus flags in the BITstatus field Any asserted bits in this field imply that the corresponding sensorStatus field signal if asserted will cause the sensorStatus and masterStatus flags to be asserted in the BITstatus field Doc 7430 3810 Rev 02 Page 78 DMU380ZA Series User s Manual MEMSIC gt 10 Warranty and Support Information 10 1 Customer Service As a MEMSIC customer you have access to product support services which include e Single point return service e Web based support service e Same day troubleshooting assistance e Worldwide MEMSIC representation e Onsite and factory training available e Preventative maintenance and repair programs e Installation assistance available 10 2 Contact Directory
53. C IGS Command niea sono do bossa S S 67 5 5 2 Del PICOS Command aenea et tine DL see eiene P bem uU 68 So Read Fields Command s 59 522 565 2694 9 9239592950285 0832 8 650 2020 9062699555055 0620 850000850 69 8 10 Read Fields Response 2 aset ia es eia erenn EE esses Do bai ue Se bagas 69 8 11 Get Pields Command eese teretes d psu EP aA E Ceu UR Ud IR bU pP Eee Read Papa RUE 69 8 12 GE ICTS RESPONSE canis sai eode oou inb ni CRS A nu 70 9 DMU380ZA Advanced UART Port BIT eese 71 9 1 Built In Test BIT and Status Fields eeeceeeeeere ne 71 9 2 Master BIT and Status BITstatus Field eeeeen 73 0 9 ae ate EL Vis 222 99922 0 02020 22998 9 0 292503502 99892 0 20800 5200 E 9 2 9 209 525 74 9 4 hardwarePowerBIT Field escussione Ee 74 9 5 hardwareEnvironmentalBIT Field eese eene 74 dO COMB MO E MM 74 Dock 7430 3810 Rev 02 Page iii DMU380ZA Series User s Manual MEMSIS gt 97 com enal ABIT ur poetics tesenaes sacs descia utii can EEr 15 do COMI uri BIEL ERREUR 75 99 vici 75 9 10 softwareAlgorithmBIT Field eeeessssssssssssseeeeeeeeeen nnn 76 9 11 SoltwWare Data BET Piel d s sc scsstmvacsisarsavensinvetabssndasessinvacebuintavensiaveiebuundaseusiesesesios 76 9 12 bardwareStatus Field uci tree Be eee ee 76 9 13 comStatus PIC oec enetoserste bes gene co
54. C gt imelTOW DU TOW snc fo GPS Brus U2 MesterBIT and Staus 7 4 8 Angle Data Packet B2 Custom VG Data Angle Data B2 0x4232 Packet Type Length Payload 0x5555 0x4232 lt B2 payload gt lt CRC U2 gt This packet contains selected angle and sensor data B2 Payload Contents 360 2M6 3605 26 4 zRateCorrected 12 T pi 2M6 rad s Z angular rate corrected 12607 2 16 sec s med fe amm fo Reneon timelTOWtruncated ske De _ sync to GPS truncated to two wis Doc 7430 3810 Rev 02 Page 62 DMU380ZA Series User s Manual MEMSIC gt 8 DMU380ZA Advanced UART Port Commands The advanced commands allow users to programmatically change the DMU380ZA Series settings This section of the manual documents all of the settings and options contained under the Unit Configuration tab within NAV VIEW Using these advanced commands a user s system can change or modify the settings without the need for NAV VIEW 8 1 Configuration Fields Configuration fields determine various behaviors of the unit that can be modified by the user These include settings like baud rate packet output rate and type algorithm type etc These fields are stored in EEPROM and loaded on power up These fields can be read from the EEPROM using the RF command These fields can be written to the EEPROM affecting the default power up behavior using the WF command The current value of these fields which
55. Do not reverse the power leads or damage may occur 2 1 3 Serial Data Interface The user can select the serial interface used with the DMU380ZA by controlling the logic level on connector pin 7 at system startup If pin 7 is left floating then the DMU380ZA is configured for SPI communications on pins 3 6 Pin 7 is set as an output and used as the DATA READY discrete for SPI communications Additionally the user can synchronize the output data on the SPI port by providing a 1 KHz input pulse on Pin 2 For the complete SPI interface definition please refer to Section 5 If the connector pin 7 is grounded then the DMU380ZA is configured for low level UART output on pins 3 and 4 This is a standard UART asynchronous output data port For the complete UART interface definition please refer to Sections 6 8 Note that the two output port interface methods are controlled independently from each other The UART port output controls apply only to data being output over the UART port and the SPI output controls apply only to data being output over the SPI port 2 14 External GPS Aiding VG380ZA AHRS380ZA and INS380ZA The VG380ZA AHRS380ZA INS380ZA allows the use of an external GPS receiver to be connected the secondary UART port The user is required to configure the GPS receiver to output the GPS messages that the DMU380ZA Series expects Table 4 shows the supported GPS protocols and guidelines for configuration Note that the details of the GPS messa
56. Figure 18 IMU380ZA 200 Default Orientation Field 0x006B Table 36 DMU380 Orientation Definitions Description Bit Men xass o Ocpsieiznghe Zass e Ocspsieizmgeie There are 24 possible orientation configurations See Table 37 Setting Writing the field to anything else generates a NAK and has no effect Dock 7430 3810 Rev 02 Page 64 DMU380ZA Series User s Manual MEMSIC gt Table 37 DMU380 Orientation Fields 0x0000 0x0009 0x0023 mou mak ur Co E pu om sy uu oec o T T Ux The default factory axis setting for all other DMU380 family model s orientation field is Ux Uy Uz which defines the base of the DMU380 pointing in the Z direction and the Y direction going from the serial number label at the end through the connector of the DMU380 The user axis set X Y Z as defined by this field setting is depicted in Figure 19 below Y Uy Pitch Yaw Z Uz Figure 19 IMU380ZA 209 409 VG AHRS INS380ZA 200 400 Default Orientation Field 0x0000 Doc 7430 3810 Rev 02 Page 65 DMU380ZA Series User s Manual MEMSIC gt 8 5 User Behavior Switches This field allows on the fly user interaction with behavioral aspects of the algorithm See Table 38 Table 38 DMU380 Behavior Switches pem om um Free Integrate O use feedback to stabilize the algorithm 1 6DOF inertial integration without stabilized feedback Use Mags 1 O Do not use mags
57. MEMSIC DMUS3SOZA Series USER MANUAL Document Part Number 7430 3810 02 MEMSIC Inc 1759 McCarthy Blvd Milpitas CA 95035 Tel 408 964 9700 Fax 408 854 7702 email infoca memsic com website www memsic com A WARNING This product has been developed by MEMSIC exclusively for commercial applications It has not been tested for and MEMSIC makes no representation or warranty as to conformance with any military specifications or that the product is appropriate for any military application or end use Additionally any use of this product for nuclear chemical biological weapons or weapons research or for any use in missiles rockets and or UAV s of 300km or greater range or any other activity prohibited by the Export Administration Regulations is expressly prohibited without the written consent of MEMSIC and without obtaining appropriate US export license s when required by US law Diversion contrary to U S law is prohibited 02014 MEMSIC Inc All rights reserved Information in this document is subject to change without notice MEMSIC SoftSensor INS380ZA AHRS380ZA VG380ZA and IMU380ZA are registered trademarks of MEMSIC Inc Other product and trade names are trademarks or registered trademarks of their respective holders DMU380ZA Series User s Manual MEMSIC gt Table of Contents e rodo 01 t I I LL Manual VET EM 05 20 92 990059160 99900956250268 2065828 95000990 8
58. Message 0x5746 numFields 2 Write Fields Reply MUNI 0x5346 numFields 4 Set Fields Input 0x5346 meena Set Fields Reply Response Message 0x5246 numFields 2 Read Fields Input i 0x5246 numFields 4 Read Fields Reply uM n 0x4746 numFields 2 Get Fields Input E Dock 7430 3810 Rev 02 Page 49 M AJ 0x4152 gt A 0x1515 0x5743 2 AHRS INS 0x4344 Output Messages Status amp Other Polled Only 0x4944 0x5652 0x5430 Output Messages Measurement Data Continuous or Polled 0x5330 CD 0x5331 0x4131 0x4132 Z 0x4E30 Z 0x4E31 0x4231 0x4232 Advanced Commands O Cc z Dl v o z z G 4 UJ UJ I gt C Tl Tl Ti Ti No O No em DMU380ZA Series User s Manual MEMSIS gt GF 0x4746 numFields 4 Get Fields Reply ALL 1 Response Message Doc 7430 3810 Rev 02 Page 50 DMU380ZA Series User s Manual MEMSIC gt 7 DMU380 Standard UART Port Commands and Messages T Link Test 7 1 1 Ping Command Ping PK 0x504B Packet Type Length Termination 0x5555 0x504B ER The ping command has no payload Sending the ping command will cause the unit to send a ping response To facilitate human input from a terminal the length and CRC fields are not required Example 0x5555504B009ef4 or 0x5555504B 7 1 2 Ping Response Ping PK 0x504B Packet Type Length 0x5555 0x504B lt CRC U2 gt The unit will se
59. ON Size ARGUMENTS queue ptr is pointer to the queue RETURNS return the number of items in the queue CkCkCkCk kk kCk kk k ck kk ck ck k kk kk ck ck kk k ck k ck ck k kc k ck k kc k ck k ck ck k kk ck kc kc k kk ck ck k kc k ck k ck ck kk ck ck k ck ck k kc kck k kck kk kk int oizetQUEUE TYPE queue ptr return queue ptr gt count KKK KK KK KK KK KK RK KK KK KKK KKK KK KKK Ck KC KK Kk Kk Ck KKK ck k Ck ck k ck ck ck k ck kck ck ck ck k ck ck k kk kk FUNCTION Empty ARGUMENTS queue ptr is pointer to the queue RETURNS return 1 if empty O if not HK KK KK RK k kk kk k ck k kk ck k kc k ck kc k ck kk k ck k kc k ck kk ck kk ck ck k kc k ck Ck ck ck k kk ck kc k ck kk ck ck k kc k ck k ck ck kk kck ck kck kk kk int Empty QUEUE TYPE queue ptr return queue ptr count lt 0 f RKCKCKCK kk kk kk Ck KK KK kk kk kk KK KK KK kk Ck Ck kk ck k kk ck k ck ck ck k ck ck k kc kck kc k ck k kc k ko k kk k FUNCTION Full ARGUMENTS queue ptr is pointer to the queue RETURNS return 1 if full O if not full KK kc k kCk kk k ck kk ck ck kk ck kk ck ck kk ck ck k ck ck kk k ck k kc k ck kc k ck k kc k ck k kc k kk ck ck kk ck ck k ck ck k kc k ck k ck ck ck ckckck k kck kk kk int FOLI QUEDE TYPE queue ptr return queue ptr gt count gt MAXQUEUE Doc 7430 3810 Rev 02 Page 101 DMU380ZA Series User s Manual MEMSIC Appendix D Sample Packet Decoding 5555 4132 le 0006ffe4ed9lfffOfffdffedfff7fff9f3312c642ce12d8500010
60. P commands Orientation See To configure the axis orientation select the desired measurement for each axes NAV Figure 6 VIEW will show the corresponding image of the VG380ZA so it easy to visualize the and mode of operation See Section 8 4 Orientation Field settings for the twenty four possible Figure 7 orientation settings The default setting points the connector AFT Filter The low pass filters are set to a default of 5Hz for the accelerometers and 20 Hz for the Settings 5 angular rate sensors There is one filter setting for all three angular rate sensors There 10 20 50 Hz are two settings for the accelerometers one for the X and Y axes and a separate setting for the Z axis The reason for a separate setting in the Z axis is that in many installations the Z axis vibration level is much higher than in the X and Y axes and it can prove helpful to filter the Z axis at a lower cutoff than the X and Y axes The Freely Integrate setting allows a user to turn the VG380ZA into a free gyro In free Integrate gyro mode the roll pitch and yaw are computed exclusively from angular rate with no kalman filter based corrections of roll pitch or yaw When turned on there is no coupling of acceleration based signals into the roll and pitch As a result the roll pitch and yaw outputs will drift roughly linearly with time due to sensor bias For best performance the Freely Integrate mode should be used after the algorithm has initia
61. QUEUE TYPE queue ptr int retval 0 LE queue ptr coounmt lt U retval 0 queue is empty else queue prr gt count item queue ptr entry queue ptr rronr queue ptr gt front queue ptr gt front l MAXQUEUE retval 1 Doc 7430 3810 Rev 02 Page 99 DMU380ZA Series User s Manual MEMSIC return retval Jf RKCKCKCK AA KKK KK KK Kk KKK KKK KK KK KK KK kk KK kk Ck Ck kk ck ck k ck ck k ck ck ck k ck ck k ck ck ck k ck ck kk kk FUNCTION peekByte returns 1 byte from buffer without popping ARGUMENTS queue ptr is pointer to the queue to return byte from index is offset into buffer to which byte to return RETURNS 1 byte REMARKS does not do boundary checking please do this first CkCkCkCkck kk KK ck kk ck ck kk ck kk k ck k kc k ck kc k ck kk ck ck k kc k ck kk ck kk ck ck kc kc k kk ck ck k kc k ck k ck ck k kc k ck kc kck kk kck k kck kk kk char peekByte QUEUE TYPE queue ptr unsigned int index char byte int firstIndex firstindex queue ptr gt front index lt MAXQUEUE byte queue DLEI entry rirstrindex return byte f RKCKCKCK AA kk Ck kk kk kk KK kk kk Kk KK kk OK KK ck ck kck ck k ck ck ck k ck kck ck ck ck k ck ck kk kc ko k kk k FUNCTION peekWord returns 2 byte word from buffer without popping ARGUMENTS queue ptr is pointer to the queue to return word from index is offset into buffer to which word to return RETURNS 2 byte word
62. United States Phone 1 408 964 9700 8 AM to 5 PM PST Fax 1 408 854 7702 24 hours Email techsupportca O memsic com Non U S Refer to website www memsic com 10 3 Return Procedure 10 3 1 X Authorization Before returning any equipment please contact MEMSIC to obtain a Returned Material Authorization number RMA Be ready to provide the following information when requesting a RMA e Name e Address e Telephone Fax Email e Equipment Model Number e Equipment Serial Number e Installation Date e Failure Date e Fault Description e Will it connect to NAV VIEW 3 X 10 3 2 Identification and Protection If the equipment is to be shipped to MEMSIC for service or repair please attach a tag TO THE EQUIPMENT as well as the shipping container s identifying the owner Also indicate the service or repair required the problems encountered and other information considered valuable to the service facility such as the list of information provided to request the RMA number Place the equipment in the original shipping container s making sure there is adequate packing around all sides of the equipment If the original shipping containers were discarded use heavy boxes with adequate padding and protection Doc 7430 3810 Rev 02 Page 79 DMU380ZA Series User s Manual MEMSIS gt 10 3 3 Sealing the Container Seal the shipping container s with heavy tape or metal bands strong enough to handle the weight of the equipment and the co
63. VesonSH 4N oo U E ZesDemer 7 3 2 Version Data Packet Version Data VR 0x5652 Packet Type Length Payload 0x5555 0x5652 lt VR payload gt lt CRC U2 gt This packet contains firmware version information majorVersion changes may introduce serious incompatibilities minorVersion changes may add or modify functionality but maintain backward compatibility with previous minor versions patch level changes reflect bug fixes and internal modifications with little effect on the user The build stage is one of the following O release candidate 12development 2 alpha 3 beta The buildNumber is incremented with each engineering firmware build The buildNumber and stage for released firmware are both zero The final beta candidate is v w x 3 y which 1s then changed to v w x 0 1 to create the first release candidate The last release candidate is v w x 0 z which is then changed to v w x 0 0 for release VR Payload Contents Dock 7430 3810 Rev 02 Page 54 DMU380ZA Series User s Manual MEMSIC gt 0 majorverson Ui Major fmware version 1 minorVersion ui Minor fmware version 2 ph qu Paio 3 stage Development Stage O release candidate 1 development 2 alpha 3 beta buldNumber Ut Build number 7 3 3 Test 0 Detailed BIT and Status Packet Test T0 0x5430 Packet Type Length Payload 03 3x5555 0x5430 TO payload lt CRC U2 gt This packet contains
64. Volt twoFiveRef sixVolt grdRef 4 environmentalError gt hardwareEnvironmentalBIT Field pcbTemp combrror e combIT Field 4 serialAError gt comSerialABIT Field transmitBufferOverflow receiveBufferOverflow ramingError breakDetect Doc 7430 3810 Rev 02 Page 71 DMU380ZA Series User s Manual MEMSIS gt parityError serialBError gt comSerialBBIT Field transmitBufferOverflow receiveBufferOverflow ramingError breakDetect parityError softwareError e softwareBIT Field algorithmError gt softwareAlgorithmBIT Field initialization overRange missedIntegrationStep 4 dataError gt softwareDataBIT Field calibra onCRCError magAlignOutOfBounds gt masterStatus hardwareStatus e hardwareStatus Field 4 unlockedIPPS enabled by default on INS 4 unlockedInternalGPS enabled by default on INS 4 noDGPS 4 unlockedEEPROM comstatus e comStatus Field 4 noExternalGPS enabled by default on VG and AHRS softwareStatus e softwareStatus Field algorithmInitialization enabled by default 4 highGain enabled by default 4 attitudeOnly Algorithm 4 turnSwitch sensorStatus Doc 7430 3810 Rev 02 Page 72 DMU380ZA Series User s Manual MEMSIC gt e sensorStatus Field overRange enabled by default 9 2 Master BIT and Status BlTstatus Field The BITstatus field is the global indication of health and status of the DMU380ZA Series product See Table 41 The
65. al GPS data is available 9 14 softwareStatus Field The softwareStatus field contains flags that indicate various software conditions and alerts that are not errors or problems See Table 53 The softwareStatus flag in the BITstatus field is the bit wise OR of the logical AND of the softwareStatus field and the softwareStatusEnable field The softwareStatusEnable field is a bit mask that allows the user to select items of interest that will logically flow up to the masterStatus flag Table 53 DMU380 Software Status Field softwareStatusField Bits Meaning algorithminit 0 0 normal 1 the algorithm is in initialization mode 9 15 sensorStatus Field The sensorStatus field contains flags that indicate various internal sensor conditions and alerts that are not errors or problems See Table 54 The sensorStatus flag in the BITstatus field is the bit wise OR of the logical AND of the sensorStatus field and the sensorStatusEnable field The sensorStatusEnable field is a bit mask that allows the user to select items of interest that will logically flow up to the masterStatus flag Table 54 DMU380 Sensor Status Field sensorStatus Field Bis Meaning overRange ioc 4 0 not asserted 1 asserted Reserved 9 16 Configuring the Master Status The masterStatus byte and its associated programmable alerts are configured using the Read Field and Write Field command as described in Section 8 Advanced Commands Table 5
66. alues When all selections have been finalized simply press the Set Values button to change the selected settings Unit Configuration General Advanced BIT Configuration Field Modify Current Value Value to Set User Behavior Switches Freely Integrate B Use Mags B Use GPS O Stationary Yaw Lock Restart Over Range E Dynamic Motion a1 itd 1 0 00000 ES 0 00000 0 00000 0 00 0 40 X Hard Iron Bias Y Hard Iron Bias Soft Iron Scale Ratio Heading Track Offset I Turn Switch Threshold 10 00 10 00 15 00 Filter XZ Accel e Filter Y Accel 0 04910 0 00238 0 99997 22 50 Filter Rate Sensor i Set Values Temporary reset after reboot C Permanant saved after reboot Figure 25 Advanced Settings Bit Configuration The third and final tab of the unit configuration window is Bit Configuration See Figure 26 This tab allows the users to alter the logic of individual status flags that affect the masterStatus flag in the master BITstatus field available in most output packets By enabling individual status flags users can determine which flags are logically OR ed to generate the masterStatus flag This gives the user the flexibility to listen to certain indications that affect their specific application The masterFail and all error flags are not configurable These flags represent serious errors and should never be ignored Do
67. and the subsequent number of data words listed in Table 20 3 Care must be taken when switching between data packets as values returned during the first burst read of a new packet are invalid A single read cycle is needed to populate the internal burst mode register subsequent reads from the same packet contain valid information 4 During a burst read the chip select line nSS can be controlled in one of two ways e Toggle nSS in between each of the 16 bit words as shown in Figure 11 e Set and hold nSS low during the entire read After the transfer is complete set chip select high Doc 7430 3810 Rev 02 Page 36 DMU380ZA Series User s Manual MEMSIC 5 3 Output Data Registers Output data registers hold the sensor information as it is measured they are overwritten only when new data is available Table 21 lists each register its memory address and its conversion factor Note the scale factor described below only applies to the values in the data registers and standard burst mode Scale factors for the other output data packets follow the values listed in Section 7 4 Table 21 DMU380ZA Data Output Registers Read Address Function X RATE 0x04 X Y Z axis rate sensor information twos complement format Y RATE conversion factor 200 LSB sec default changes with selected Z RATE dynamic range Table 28 X ACCEL Ox0A Y ACCEL OC et X Y Z axis accelerometer information twos complement format La pue conve
68. are terms and scale factor errors The largest error in the orientation propagation is associated with the rate sensor bias terms The Extended Kalman Filter EKF module provides an on the fly calibration for drift errors including the rate sensor bias by providing corrections to the Integration to Orientation block and a characterization of the gyro bias state In the VG380ZA the internally computed gravity reference vector provides a reference measurement for the EKF when the VG380ZA 1s in quasi static motion to correct roll and pitch angle drift and to estimate the X and Y gyro rate bias Because the gravity vector has no horizontal component the EKF has no ability to estimate either the yaw angle error or the Z gyro rate bias The VG380ZA adaptively tunes the EKF feedback in order to best balance the bias estimation and attitude correction with distortion free performance during dynamics when the object is accelerating either linearly speed changes or centripetally false gravity forces from turns Because centripetal and other dynamic accelerations are often associated with yaw rate the VG380ZA maintains a low passed filtered yaw rate signal and compares it to the turnSwitch threshold field user adjustable When the user platform to which the VG380ZA is attached exceeds the turnSwitch threshold yaw rate the VG380ZA lowers the feedback gains from the accelerometers to allow the attitude estimate to coast through the dynamic situation with pr
69. areBIT field contains flags that indicate various types of internal hardware errors See Table 42 Each of these types has an associated message with low level error signals The hardwareError flag in the BITstatus field is the bit wise OR of this hardwareBIT field Table 42 DMU380 Hardware BIT Field hardwareBIT Field Bits Meaning Category powetmr 0 Ocmoma t emr S reseved deas NA o 94 hardwarePowerBIT Field The hardwarePowerBIT field contains flags that indicate low level power system errors See Table 43 The powerError flag in the hardwareBIT field is the bit wise OR of this hardwarePowerBIT field Table 43 DMU380 Hardware Power BIT Field hardwarePowerBiT Field Bis Meaning Tento none O fomnomaiizonoidoundo sn wow e O noma izouofbunds Sot gd 8 O nomazouofbunis Sot Re o qua 95 hardwareEnvironmentalBIT Field The hardwareEnvironmentalBIT field contains flags that indicate low level hardware environmental errors See Table 44 The environmentalError flag in the hardwareBIT field is the bit wise OR of this hardwareEnvironmentalBIT field Table 44 DMU380 Hardware Environment BIT Field hardwareEnvironmentalBIT Field Bits Meaning Category pcbTemp 0 4 O normal 1 out of bounds Resewed NA 9 6 comBIT Field The comBIT field contains flags that indicate communication errors with external devices See Table 45
70. arities from the sensor data Additionally any advanced user settings such as axes rotation are applied to the IMU data The 200Hz IMU data is continuously being maintained inside the IMU380ZA and is available at 200Hz on the SPI output port registers Digital IMU data is output over the UART port at a selectable fixed rate 100 50 25 20 10 5 or 2 Hz or on as requested basis using the GP Get Packet command The digital IMU data is available in one of several measurement packet formats including Scaled Sensor Data S1 Packet In the Scaled Sensor Data S1 Packet data is output in scaled engineering units See Section 7 of the manual for full packet descriptions IMPORTANT The Delta Theta Delta V packet is only recommended for use in continuous output mode at SHz or greater Polled requests for this packet will produce values accumulated since the last poll request and thus are subject to overflow data type wrap around 3 2 1 IMU380ZA Advanced Settings The IMU380ZA advanced settings are described in Table 6 All of the advanced settings are accessible thru NAV VIEW under the Configuration Menu Unit Configuration settings For a full definition of the SPI port please see section 5 Table 6 IMU380ZA Advanced Settings Setting Dm Comments Baud Rate 38 400 baud 9600 19200 57600 also available Packet Type S1 also available Packet Rate 100Hz This setting sets the rate at which selected Packet Type packets are out
71. b1c0300 6945 preamble type length CRC invalid 0006ffe4ed91 fffOfffdffed fff7fff9f331 2c642cel2d85 00010b1c 0300 timeITOW Hex Data Value s 00010b1c 68380 Hex Value Data 9 FFF7 0 0027 x FFF9 0 0021 y F331 1 0007 z Hex Value Data deg C 2C64 34 680 2CE1 35 062 2D85 35 562 Hex Value Data deg 0006 0 033 roll FFE4 0 154 pitch ED91 25 922 yaw Hex Value Data deg s FFF9 0 13 roll FFFD pitch FFED 0 37 yaw BIT status Field lt Field masterFail hardwareError comError softwareError reserved masterStatus hardwareStatus comStatus softwareStatus sensorStatus 0 Figure 30 Example payload from Angle Data Packet 2 A2 Doc 7430 3810 Rev 02 Page 102 DMU380ZA Series User s Manual MEMSIC 5555 5331 18 0000fffef332 fff30001fff8 23b9242624ca2aff 9681 0300 248a Iu Va preamble type length counter CRC invalid BIT status Field Hex Value Data deg C 23B9 28 241 2426 28 741 24CA 33 591 2AFF 38 968 Hex Value Data g FFFE 0 001 Hex Value Data deg s Field Value masterFail hardwareError comError softwareError oms fo omansa fo erosa o C Figure 31 Example payload from Scaled Data Packet 1 S1 Doc 7430 3810 Rev 02 Page 103 DMU380ZA Series User s Manual 5555 4e31 2a O01lbffdf3ab5bfffe0000ffe
72. c 7430 3810 Rev 02 Page 87 DMU380ZA Series User s Manual MEMSIC Unit Configuration General Advanced BIT Configuration By enabling a given status BIT the signal will be included in the corresponding category BIT and in the master status BIT sent by the DMU Field Modify Current Value Enable Disable Hardware Status Enable O Unlocked 1PPS O Unlocked Internal GPS O No DGPS O Unlocked Eeprom rA E m Software Staus Enable L algorithm Initializing O High Gain O Altitude Only alg O Turn Switch ERI Sensor Status Enable f Bl Sensor Over Range Comm Status Enable O No External GPS Get All Values Set Values Temporary reset after reboot Permanant saved after reboot Figure 26 BIT Configuration Mag Alignment Procedure gt IMPORTANT The following section only applies to DMU380ZA Series products with magnetometers AHRS and INS380ZA If your particular model does not utilize magnetometers for heading or performance you can disregard the following section Hard Iron Soft Iron Overview The AHRS and INS380ZA products use magnetic sensors to compute heading Ideally the magnetic sensors would be measuring only earth s magnetic field to compute the heading angle In the real world however residual magnetism in your system adds to the total magnetic field measured This residual magnetism called hard iron and soft iron will create errors in the heading measurement if it is not ac
73. c situations but care must be taken to ensure that the duty cycle of the turn switch generally stays below 10 during the vehicle mission A high turn switch duty cycle does not allow the system to apply enough rate sensor bias correction and could allow the attitude estimate to become unstable As described in 3 3 VG380ZA theory of operation the AHRS380ZA algorithm also has two major phases of operation The first phase of operation is the high gain initialization phase During the initialization phase the AHRS380ZA is expected to be stationary or quasi static so the EKF weights the accelerometer gravity reference and Earth s magnetic field reference heavily in order to rapidly estimate the X Y and Z rate sensor bias and the initial attitude and heading of the AHRS380ZA The initialization phase lasts approximately 60 seconds and the initialization phase can be monitored in the softwareStatus BIT transmitted by default in each measurement packet After the initialization phase the AHRS380ZA operates with lower levels of feedback also referred to as EKF gain from the accelerometers and magnetometers to continuously estimate and correct for roll pitch and heading yaw errors as well as to estimate X Y and Z rate sensor bias The AHRS380ZA digital data is output over the UART port at a selectable fixed rate 100 50 25 20 10 5 or 2 Hz or on as requested basis using the GP Get Packet command The AHRS400 supports the same scal
74. ccelerometer xRateTemp 2 200 2M6 deg C X rate temperature 22 24 timel TOW U4 1 ms DMU ITOW sync to GPS BlTstatus HS fe q Master BIT and Status 7 4 5 Nav Data Packet 0 Nav Data N0 0x4E30 zRateCorrected um um xRateCorrected 7 pi 2416 rad s X angular rate corrected 1260 2 16 sec E LN DNEE 12 12 12 12 12 12 12 12 12 12 Packet Type Length Payload 0x5555 0x4E30 lt NO payload lt CRC U2 gt This packet contains navigation data and selected sensor data scaled in most cases to a signed 2 16 2 s complement number Data involving angular measurements include the factor pi in the scaling and can be interpreted in either radians or degrees Angles scaled to a range of p1 p1 or 180 deg to 180 deg Angular rates scaled to range of 3 5 pi pi or 630 deg sec to 630 deg sec Accelerometers scaled to a range of 10 10 g Temperature scaled to a range of 100 100 C Velocities are scaled to a range of 256 256 m s Altitude is scaled to a range of 100 16284 m using a shifted 2 s complement representation Longitude and latitude are scaled to a range of p1 p1 or 180 deg to 180 deg Doc 7430 3810 Rev 02 Page 59 DMU380ZA Series User s Manual MEMSIC gt NO Payload Contents Byte Offset rollAngle 12 2 pi 2M6 Radians Roll angle 3607 2 16 2 pitchAngle 2 2 pi 2 16 Radians Pitch angle 360 2 16 4 yawAngleTrue 12 2 pi 2 16
75. ce Unlike the AHRS400 and earlier MEMSIC AHRS Series products the AHRS380ZA can be configured to turn on and off the magnetic reference for user defined periods of time see Section 8 Advanced Commands In addition the AHRS380ZA can accept external GPS data refer to the INS380ZA section for details for improved performance At a fixed 200Hz rate the AHRS380ZA continuously maintains the digital IMU data as well as the dynamic roll pitch and heading As shown in Figure 4 after the Sensor Calibration Block the IMU data 1s passed to the Integration to Orientation block The Integration to Orientation block integrates body frame sensed angular rate to orientation at a fixed 200 times per second within all of the DMU380ZA Series products For improved accuracy and to avoid singularities when dealing with the cosine rotation matrix a quaternion formulation is used in the algorithm to provide attitude propagation As also shown in the software block diagram the Integration to Orientation block receives drift corrections from the Extended Kalman Filter or Drift Correction Module In general rate sensors and accelerometers suffer from bias drift misalignment errors acceleration errors g sensitivity nonlinearity square terms and scale factor errors The largest error in the orientation propagation is associated with the rate sensor bias terms The Extended Kalman Filter EKF module provides an on the fly calibration for drift errors includin
76. cent is the phase of flight in which an aircraft decreases altitude for an approach to landing The aircraft is under vertical deceleration until it captures a glide slope See Figure 8 Landing is the last part of a flight where the aircraft returns to the ground See Figure 8 Pre launch or known straight and level un accelerated flight Straight and level Normal Dynamics Normal Dynamics Pre launch or Climb Maneuver Descent known straight and mm level un accelerated Ig flight Dynamics Prelaunch Takeoff Landing Recommended Advanced Settings Figure 8 Typical flight profiles of fixed wing aircraft and the corresponding advanced settings Dock 7430 3810 Rev 02 Page 31 DMU380ZA Series User s Manual MEMSIC 5 DMUS380ZA SPI Port Interface Definition The DMU380ZA provides a SPI interface for data communications This section of the user s manual defines the DMU380ZA register map register control capabilities and the data register reading and writing methodologies The DMU380ZA operates as a slave device The master device must be configured to communicate with the DMU380ZA using the following settings e Data transferred in 16 bit word length and MSB first e cLK 2 0 MHz e CPOL clock polarity and CPHA 1 clock phase Additional operational requirements are described in Section 5 8 5 1 DMU380ZA Register Map Table 18 describes the DMU380ZA register map Table 18 DMU380Z
77. counted for In addition magnetic material can change the direction of the magnetic field as a function of the input magnetic field This dependence of the local magnetic field on input direction is called the soft iron effect Dock 7430 3810 Rev 02 Page 88 DMU380ZA Series User s Manual MEMSIC gt The AHRS and INS380ZA products can actually measure the constant magnetic field that is associated with your system and correct for it The AHRS and INS380ZA products can also make a correction for some soft iron effects The process of measuring these non ideal effects and correcting for them is called the Mag Alignment Procedure Performing a Mag Alignment Procedure will help correct for magnetic fields that are fixed with respect to the DMU380ZA Series product It cannot correct for time varying fields or fields created by ferrous material that moves with respect to the DMU380ZA Series product The AHRS and INS380ZA products account for the extra magnetic field by making a series of measurements and using these measurements to model the hard iron and soft iron environment in your system using a two dimensional algorithm The AHRS and INS380ZA products will calculate the hard iron magnetic fields and soft iron corrections and store these as calibration constants in the EEPROM The Mag Alignment Procedure should always be performed with the AHRS or INS380ZA product installed in the user system If you perform the calibration process with
78. d be read from the DMU380ZA when the data ready line is set see Section 5 7 1 Power on ARST pulled low of master following power on Vcc nRST released after z system configured nRST held low during nRST master boot up sequence tReset Delay DR Set nSS low to read data A when Data Ready line is set Figure 15 Startup Timing SPI Timing The timing requirements for the SPI the are listed in Table 31 and illustrated in Figure 16 and Figure 17 In addition the following operational constraints apply to the SPI communications e The unit operates with CPOL 1 polarity and CPHA 1 phase e Data is transmitted 16 bits words Most Significant Bit MSB first Table 31 SPI Timing Requirements SPI cock frequency Time between successive clock cycles Figure 16 NSS setup time prior to clocking data Figure 17 tv miso Time after falling edge of previous clock edge that MISO data 20 nsec bit is invalid Figure 17 Data input setup time prior to rising edge of clock Figure 17 Data input hold time following rising edge of clock Figure 17 4 nec nsec min nSS hold time following clock signal Figure 17 nsec 4 nSS e CMM A DELAY lt e Figure 16 Delay Time Doc 7430 3810 Rev 02 Page 44 DMU380ZA Series User s Manual MEMSIC nSS tsu Nss n Nss ax AJ tv MISO uso e fine eo E SU MO vos TD C Yi o s IT Figure 17 SPI Timing Diagram
79. ding provided from the magnetic field sensor readings When Use Mags is turned OFF the heading yaw angle measurement of the AHRS380ZA will drift and freely integrate In effect this setting converts an AHRS380ZA into the functionality of the VG380ZA However unlike a VG380ZA this can be done on a selectable basis and changed in real time during a mission The reason for this setting is to give the user an ability to turn off the magnetometer stabilization when severe magnetic distortion may be occurring This setting is desirable when the user system temporarily Doc 7430 3810 Rev 02 Page 21 DMU380ZA Series User s Manual MEMSIC moves in close proximity to a large ferrous object When the Use Mags switch is turned from OFF to ON the AHRS380ZA will reinitialize the yaw heading angle with the compass reading provided from the magnetic field sensor readings Restart On This setting forces an algorithm reset when a sensor over range occurs i e a rotational Over rate on any of the three axes exceeds the maximum range The default setting is OFF for Range the AHRS380ZA Algorithm reset returns the AHRS380ZA to a high gain state where the AHRS380ZA rapidly estimates the gyro bias and uses the accelerometer feedback heavily This setting is recommended when the source of over range is likely to be sustained and potentially much greater than the rate sensor operating limit Large and sustained angular rate over ranges result in unrecoverable err
80. ds of data registers Single Register Polled Read Figure 9 illustrates a polled mode read of a single register x axis rate sensor data which is composed of two bytes starting at register address 0x04 In this example the SPI master initiates a register read by clocking in the address followed by 0x00 i e 0x0400 via MOSI this combination is referred to as a read command This is followed by 16 zero bits to complete the SPI data transfer cycle As the master transmits the read command over MOSI the DMU380ZA transmits information back over MISO In this transmission the first data word sent by the DMU380ZA as the read command is sent consists of 16 bits of non applicable data The subsequent 16 bit message contains the x axis rate sensor information most significant byte followed by least significant byte nSS i CLK MOSI 0x0400 0x0000 gt Figure 9 Single Register Read via Polled Mode A SPI cycle consists of 16 clock cycles A read command consists of an 8 bit register address and a zero byte 0x00 Dock 7430 3810 Rev 02 Page 34 DMU380ZA Series User s Manual MEMSIC gt Multiple Register Polled Read Figure 10 illustrates a polled mode read of multiple registers In this case the SPI master transmits an initial read command the desired register address appended by 0x00 across MOSI followed by any number of additional read commands one for each register of interest The DMU380ZA transfers
81. e configured to output data over a SPI Port or a low level UART serial port The port Doc 7430 3810 Rev 02 Page 2 DMU380ZA Series User s Manual MEMSIC gt choice is user controlled by grounding the appropriate pin on the connector The DMU380 low level UART output data port is supported by MEMSIC s NAV VIEW 3 X a powerful PC based operating tool that provides complete field configuration diagnostics charting of sensor performance and data logging with playback Doc 7430 3810 Rev 02 Page 3 DMU380ZA Series User s Manual MEMSIC 2 Interface 2 1 Electrical Interface 2 1 1 Connector and Mating Connector The DMU380ZA main connector is a SAMTEC FTM 110 02 F DV P defined in Figure 1 The mating connector that can be used is the SAMTEC CLM 110 02 REF PIN1 PIN 2 PIN 19 Figure 1 DMU380ZA Interface Connector The connector pin definitions are defined in Table 3 Table 3 DMU380ZA Interface Connector Pin Definition Reserved factory use only Data Ready SPI Communication Data Ready SPI UART Port Select External Reset NRST E Doc 7430 3810 Rev 02 Page 4 DMU380ZA Series User s Manual MEMSIC gt Reserved factory use only Reserved factory use only 2 1 2 Power Input and Power Input Ground Power 1s applied to the DMU380ZA on pins 10 through 15 Pins 13 15 are ground Pins 10 12 accepts 3 to 5 VDC unregulated input Note that these are redundant power ground input pairs A WARNING
82. e drift correction of the 6 DOF inertial sensor cluster For the AHRS product a 3 axis magnetometer is used for correcting the drift on yaw heading angle For the INS product a 3 axis magnetometer and a GPS receiver are used for correcting the drift on yaw heading angle increasing the accuracy of the attitude estimation by incorporating these sensor signals into the EKF and providing a navigation solution The common aiding sensor for the drift correction for the attitude 1 e roll and pitch only is a 3 axis accelerometer This is the default configuration for the VG product Doc 7430 3810 Rev 02 Page 10 DMU380ZA Series User s Manual MEMSIC gt i acces rates mags e GPS position Atitude fal NAV Mode NAVA440 of AHR S340 with Erian G hi AHRS Made Al RS440 or NAVA4O w lass of GPS accels rates atstude heading yaw free dining accels rates atitude velocity GPS position fc WSS Mode VOSSO with External GPS al VG Mode vG4401 Figure 5 Functional Block Diagram of INS AHRS and VG Default Operating Mode 3 1 DMU380ZA Series Default Coordinate System The DMU380ZA Series Inertial System default coordinate systems are shown in Figure 6 and Figure 7 As with many elements of the DMU380ZA Series the coordinate system is configurable with either NAV VIEW or by sending the appropriate serial commands over the UART port These configurable elements are known as Advanced Settings This section of the manual descr
83. ed sensor and angle mode packet format of the VG380ZA The AHRS380ZA defaults to the Al Angle Packet which outputs the roll angle pitch angle yaw angle and digital IMU data In the AHRS380ZA the A1 packet contains accurate magnetometer readings See Sections 6 and 7 of the manual for full packet descriptions All data is also available on the SPI output port registers Please refer to section 5 for a complete description of the SPI port functionality IMPORTANT For proper operation the AHRS380ZA relies on magnetic field readings from its internal 3 axis magnetometer The AHRS380ZA must be installed correctly and calibrated for hard iron and soft iron effects to avoid any system performance degradation See section 3 4 1 for information and tips regarding installation and calibration 3 4 1 AHRS380ZA Magnetometer Calibration and Alignment The AHRS380ZA uses magnetic sensors to compute heading Ideally the magnetic sensors would measure only the earth s magnetic field to compute the heading angle In the real world however residual magnetism in your system will add to the magnetic field measured by the AHRS380ZA This extra magnetic field will create errors in the heading measurement if they are not accounted for These extra magnetic fields are called hard iron magnetic fields In addition magnetic material can change the direction of the magnetic field as a function of the input magnetic field This dependence of the local Doc
84. ees The WC command has two options auto termination and manual termination With auto termination the AHRS380ZA tracks the yaw movement and after 380 degrees of rotation returns the calibration complete response CD The auto termination sequence can falsely terminate if the 360 degree rotation is not completed within 2 minutes of the WC command initiation Manual termination requires the user to send a second WC command with the termination code in the payload Manual termination is a good option when the user system moves very slowly e g large marine vessel and completing the 360 degree rotation may require more than two minutes The calibration complete CD command response message contains the X and Y hard iron bias as well as the soft iron ratio and soft iron phase angle This information can be interpreted to give an indication of the quality of the calibration See the section Hard Iron Soft Iron Overview in Appendix A Installation and Operation of NAV VIEW for more information on the hard iron bias and soft iron ratio Section 7 has programming details for the WC and CD commands N WARNING Doc 7430 3810 Rev 02 Page 20 DMU380ZA Series User s Manual MEMSIC The AHRS380ZA and INS380ZA units must be mounted at least 24 away from large ferrous objects and fluctuating magnetic fields Failure to locate the unit in a clean magnetic environment will affect the attitude solution 3 4 2
85. el error signals The softwareError flag in the BITstatus field is the bit wise OR of this softwareBIT field Table 48 DMU380 Softrware BIT Field softwareBiT Field Bis Menng Catgoy algorithmError o osmmaisenr sa Doc 7430 3810 Rev 02 Page 75 DMU380ZA Series User s Manual MEMSIS gt Reseved dens NA 9 10 softwareAlgorithmBIT Field The softwareAlgorithmBIT field contains flags that indicate low level software algorithm errors See Table 49 The algorithmError flag in the softwareBIT field is the bit wise OR of this software AlgorithmBIT field Table 49 DMU380 Software Algorithm BIT Field SoftwareAlgorithmBIT Field Bits Meaning Category initialization 0 O normal 1 error during algorithm initialization overRange 1 O normal 1 fatal sensor over range missedNavigationStep 2 O normal 1 fatal hard deadline missed for Hard navigation Reserved 3 15 N A D 9 11 softwareDataBIT Field The softwareDataBIT field contains flags that indicate low level software data errors See Table 50 The dataError flag in the softwareBIT field 1s the bit wise OR of this softwareDataBIT field Table 50 DMU380 Software Data BIT Field SoftwareDataBIT Field Bits Meaning Category calibrationCRCError 0 normal 1 incorrect CRC on Hard calibration EEPROM data or data has been compromised by a WE command magAlignOutOfBounds 1 O normal 1 hard and softiron Hard parameters are out of bou
86. end 0x000B calibration request to terminate Terminate magnetic alignment The unit will send a CC response containing the hard iron and soft iron values To accept the parameters store them 0x000B using the write magnetic calibration command Begin magnetic calibration with automatic termination Rotate the unit through 380 degrees in yaw The unit will send a CC response containing the hard iron and soft iron values upon completion of the turn To accept the 0x000C parameters store them using the write magnetic calibration command Write magnetic calibration The unit will write the parameters to EEPROM Ox000E and then send a calibration response 7 2 5 Calibrate Acknowledgement Response Calibrate WC 0x5743 Packet Type Length Payload 0x5555 0x5743 WC payload CRC U2 gt The unit will send this packet in response to a calibrate request 1f the procedure can be performed or initiated WC Payload Contents Byte Offset PO calibrationRequest Po po fo The requested calibration task 7 2 6 Calibration Completed Parameters Response Calibrate Completed CD 0x4344 Packet Type Length Payload 0x5555 0x4344 lt CD payload gt lt CRC U2 gt The unit will send this packet after a calibration has been completed Currently there is only one message of this type sent after a magnetic calibration has been completed with or without automatic termination and the parameters have been calculated Thus
87. er of advanced settings that can be changed The specific settings available vary from unit to unit and a detailed description of each unit IMU VG AHRS and INS is found in the subsequent sections of this manual All units support baud rate power up output packet type output rate sensor low pass filtering and custom axes configuration The units can be configured using NAV VIEW as described in Appendix A and also directly with serial commands as described in Sections 6 9 3 2 IMU380ZA Theory of Operation The product name IMU380ZA stands for Inertial Measurement Unit 380 and the name is indicative of the inertial measurement unit functionality that the IMU380ZA provides by providing inertial rate and acceleration data in 6 DOF six degrees of freedom The IMU380ZA signal processing chain consists of the 6 DOF sensor cluster programmable low pass filters and the signal processor for sensor error compensation The IMU380ZA as with other DMU380ZA Series variants has a UART input output port and a SPI input output port Doc 7430 3810 Rev 02 Page 12 DMU380ZA Series User s Manual MEMSIC After passing thru a digitally controlled programmable low pass filter the rate and acceleration sensor signals are obtained at 200Hz The sensor data is filtered by the processor using FIR filters The factory calibration data stored in EEPROM is used by the processor to remove temperature bias misalignment scale factor errors and non line
88. fields to read The fieldO fieldl etc are the field IDs to read RF may be used to read configuration and calibration fields from the EEPROM If at least one field is successfully read the unit will respond with a read fields response containing the field IDs and data from the successfully read fields If any field is unable to be read the unit will respond with an error response Note that both a read fields and an error response may be received as a result of a read fields command ro i nmrs Ui __ Thenumberof fields tread lfedo U2 f ThefrsteldlDtoread 3 fedi U2 f j ThesecodfeldiDtoread e Morefield Dstoread numFields2 1 Field U2 Thelastfield IDtoread 8 10 Read Fields Response Read Fields RF 0x5246 Packet Type Length Payload 0x5555 0x5246 1 numFields 4 lt RF payload gt lt CRC U2 gt The unit will send this packet in response to a read fields request if the command has completed without errors RF Payload Contents Byte Offset fo nms Ui S The number of felds read fils fu ThefstfekID read 3 coat Ul 5 m qu T eba uz _ The second feld ID s data read w e fu e e wi u Thelastfeld Dread mmFes4 fed Dda U2 Thelastfeld D s dataread 8 11 Get Fields Command Get Fields GF 0x4746 Packet Type Length Payload 0x5555 0x4746 1 numFields 2 lt GF Data gt lt CRC U2 gt
89. frame and are integrated to velocity At this point the data is blended with GPS position data and output as a complete navigation solution As shown in Figure 4 the Integration to Orientation and the Integration to Velocity signal processing blocks receive drift corrections from the Extended Kalman Filter EKF drift correction module The drift correction module uses data from the aiding sensors when they are available to correct the errors in the velocity attitude and heading outputs Additionally when aiding sensors are available corrections to the rate gyro and accelerometers are performed The INS380ZA blends GPS derived heading and accelerometer measurements into the EKF update depending on the health and status of the associated sensors If the GPS link is lost or poor the Kalman Filter solution stops tracking accelerometer bias but the algorithm continues to apply gyro bias correction and provides stabilized angle outputs The EKF tracking states are reduced to angles and gyro bias only The accelerometers will continue to integrate velocity however accelerometer noise bias and attitude error will cause the velocity estimates to start drifting within a few seconds The attitude tracking performance will degrade the heading will freely drift and the filter will revert to the VG only EKF formulation The UTC packet synchronization will drift due to internal clock drift The status of GPS signal acquisition can be monitored from t
90. g the rate sensor bias by providing corrections to the Integration to Orientation block and a characterization of the gyro bias state In the AHRS380ZA the internally computed gravity reference vector and the distortion corrected magnetic field vector provide an attitude and a heading reference measurement for the EKF when the AHRS380ZA is in quasi static motion to correct roll pitch and heading angle drift and to Dock 7430 3810 Rev 02 Page 18 DMU380ZA Series User s Manual MEMSIC gt estimate the X Y and Z gyro rate bias The AHRS380ZA adaptively tunes the EKF feedback gains in order to best balance the bias estimation and attitude correction with distortion free performance during dynamics when the object is accelerating either linearly speed changes or centripetally false gravity forces from turns Because centripetal and other dynamic accelerations are often associated with yaw rate the AHRS380ZA maintains a low passed filtered yaw rate signal and compares it to the turnSwitch threshold field user adjustable When the user platform with the AHRS380ZA attached exceeds the turnSwitch threshold yaw rate the AHRS380ZA lowers the feedback gains from the accelerometers to allow the attitude estimate to coast through the dynamic situation with primary reliance on angular rate sensors This situation is indicated by the softwareStatus gt turnSwitch status flag Using the turn switch maintains better attitude accuracy during short term dynami
91. ge of p1 p1 or 180 deg to 180 deg N1 Payload Contents Byte Offset Doc 7430 3810 Rev 02 Page 60 DMU380ZA Series User s Manual rollAngle l2 E pitchAngle yawAngleTrue longitudeGPS 2 4 2 2 2 2 2 pi 2 46 3605 26 2 pi 2 46 3605 26 2 pi 2 46 3605 26 T pil2M6 1260 26 T pil2M6 1260 26 T pil2M6 1260 26 912 216 2 pi 2 32 360 2 32 2 pi 2 32 360 2 32 2M4 2M6 MEMSIC gt Roll angle Pitch angle o o o Yaw angle true north rad s X angular rate corrected sec rad s Y angular rate corrected sec rad s Z angular rate corrected sec g Xectelerometer fg Y accelerometer g Zaccelerometer GPS Longitude GPS Latitude Is Is Is altitudeGPS xRate Temp m GPS altitude 100 16284 200 2 16 deg C X rate sensor temperature 36 timel TOW U4 1 ms DMU ITOW sync to GPS BlTstatus FEE Master BIT and Status 7 4 7 Angle Data Packet B1 Custom VG Data Angle Data B1 0x4231 Packet Type Length Payload 0x5555 0x4231 B1 payload lt CRC U2 gt This packet contains selected angle and sensor data 10 12 14 16 18 0 512 216 2 4 8 32 34 B1 Payload Contents 360 2 16 360 2 16 360 2 16 1260 2 46 sec LN E memo fg Xaxseomde o Yaxseomde 2 2 2 20 26 Doc 7430 3810 Rev 02 Page 61 DMU380ZA Series User s Manual MEMSI
92. ges can be found in the respective GPS protocol documents The user must configure the VG AHRS INS380ZA to accept external GPS information using NAV VIEW as described in Appendix A If the VG AHRS INS380ZA is parsing valid external GPS data and the GPS receiver has 3D lock then the comStatus noExternalGPS flag will be zero otherwise it will be one See Section 9 for a complete description of system status indications Since NMEA protocol does not provide vertical velocity the vertical velocity that the DMU380ZA Series estimates based upon GPS altitude changes may not be sufficient for airborne applications see Table 4 Therefore the NMEA protocol is not recommended for airborne applications Table 4 External GPS Receiver for VG AHRS INS380ZA Required Messages Required Message Rate Ublox binary NAV LLH NAV VELNED 4 Hz 9600 19200 38400 NAV STATUS 9 600 NovAtel OEM4 and BestPosB BestVelB 4Hz 9600 19200 38400 OEMV Binary 9 600 NovAtel OEMA PosVelNavDopA 4Hz 19200 38400 57600 ASCII Dock 7430 3810 Rev 02 Page 5 DMU380ZA Series User s Manual MEMSIC gt NMEA GPGGA GPVTG 4Hz 9600 19200 38400 57600 Not recommended for airborne applications 57600 is the preferred baud rate for optimum performance The secondary UART port should be configured to 8 data bits 1 start bit 1 stop bit no parity bit and no flow control 2 1 4 1 1 PPS Input Interface When using external GPS aiding for a VG AHRS INS380ZA
93. hardware and software subsystem in the INS380ZA See Sections 6 and 7 of the manual for details on the TO packet The BIT word contained within each measurement packet is detailed below The LSB Least Significant Bit is the Error byte and the MSB Most Significant Bit is a Status byte with programmable alerts Internal health and status are monitored and communicated in both hardware and software The ultimate indication of a fatal problem is the masterFail flag The softwareError bit also provides useful information regarding the status and quality of the INS380ZA magnetic alignment If the INS380ZA has not been properly magnetically calibrated the INS380ZA shall indicate a softwareError The masterStatus flag 1s a configurable indication that can be modified by the user This flag is asserted as a result of any asserted alert signals which have been enabled See Advanced Settings for details for configuring the masterStatus flags Table 13 shows the BIT definition and default settings for BIT programmable alerts in the INS380ZA Table 13 INS380ZA Default BIT Status Definitions CE mm 0 normal 1 internal software error or magAlignOutofBounds BlTstatus Field masterFail HardwareError comError softwareError masterStatus O nominal 1 one or more status alert Status O nominal 1 Internal GPS unlocked or 1PPS Status invalid 0 nominal 1 Algorithm Initialization or high gain The INS380ZA also allows a user
94. he Built In Test capability allows users of the AHRS380ZA to monitor health diagnostic and system status information of the unit in real time The Built In Test information consists of a BIT word 2 bytes transmitted in every measurement packet In addition there is a diagnostic packet TO that can be requested via the Get Packet GP command which contains a complete set of status for each hardware and software subsystem in the AHRS380ZA See Sections 6 and 7 of the Programming Guide for details on the TO packet Turn 0 5 With respect to centripetal or false gravity forces from turning dynamics or coordinated Switch deg sec turn the AHRS380ZA monitors the yaw rate If the yaw rate exceeds a given Turnswitch The BIT word contained within each measurement packet is detailed below The LSB Least Significant Bit is the Error byte and the MSB Most Significant Bit is a Status byte with programmable alerts Internal health and status are monitored and communicated in both hardware and software The ultimate indication of a fatal problem is the masterFail flag The softwareError bit also provides useful information regarding the status and quality of the AHRS380ZA magnetic alignment If the AHRS380ZA has not been properly magnetically calibrated the AHRS380ZA shall indicate a softwareError The masterStatus flag 1s a configurable indication that can be modified by the user This flag is asserted as a result of any asserted ale
95. he hardwareStatus BIT as discussed in Section 3 5 3 INS380ZA Built in Test From a cold start it typically takes 40 seconds for GPS to lock The actual lock time depends on the antenna s view of the sky and the number of satellites in view The processor performs time triggered trajectory propagation at 100Hz and will synchronize the sensor sampling with the GPS UTC Universal Coordinated Time second boundary when available As with the AHRS380ZA and VG380ZA the algorithm has two major phases of operation Immediately after power up the INS380ZA uses the accelerometers and magnetometers to compute the initial roll pitch and yaw angles The roll and pitch attitude will be initialized using the accelerometer s reference of gravity and yaw will be initialized using the leveled magnetometers X and Y axis reference of the earth s magnetic field During the first 60 seconds of startup the INS380ZA should remain approximately motionless in order to properly initialize the rate sensor bias The initialization phase lasts approximately 60 seconds and the initialization phase can be monitored in the softwareStatus BIT transmitted by default in each measurement packet After the initialization phase the INS380ZA operates with lower levels of feedback also referred to as EKF gain from the GPS accelerometers and magnetometers Digital data is output over the UART port at a selectable fixed rate 100 50 25 20 10 5 or 2 Hz or on as requested basis
96. i ai b se a E ST BEB EBB BEEBE eee BEEBE Bee EHEHE X Y ZBody wu s Lais a 3 200H z E Signal IER p Integration to Integration to 100 Hz E E Proc Attitude Velocity GPS X Y Z Body m chain Axes Rotation Position Output Accelerometers a E E ou E Hummmumumumumuuuuu m mibi E bbb Sb BEEBE BBB OP eee eee E MEME E m E a Unit Settings amp Profile m Extended Kalman Filter EKF m E a m g Drift Correction Module g Builtin Test Em E E amp Status E a a Data a E E Available to E E E E User E u m Kalman Filter and Dynamic State Model m m E E E m 1 E E E a E E E E E E E E s m E Hard Soft Iron Free Integrate UseGPS E m E E Calibration TurnSwitch Stationary Yaw E E E E a UseMags Threshold Lock E a E E E a m B Bi E B Pe BBB ee eee bl ibl bbb tenent m B E gEEEHNEEHNEHEHEHNEHEHEHENEHEEENHENEHEEHEEEEHHEEERHENEHEENERN E a El E E a g Aiding Sensors a m m o a X Y Z Gravity Reference a m m E Magnetometers Turn Rate GPS Data E E INS AHRS onl Internal Internal External m omy Computation u i E E m E SORO eee eee ee eee eo E a m ESES ESEL Figure 4 DMU380ZA Series Software Block Diagram Simplified functional block diagrams for INS AHRS and VG series products derived from Figure 4 are shown in Figure 5 to highlight key features of each product The DMU380ZA Series products are mainly differentiated by types of aiding sensors used in the EKF for th
97. ibes the default coordinate system settings of the DMU380ZA Series when it leaves the factory Figure 7 IMU380ZA 209 409 VG AHRS INS380ZA 200 400 Default Coordinate Frame Dock 7430 3810 Rev 02 Page 11 DMU380ZA Series User s Manual MEMSIS gt The axes form an orthogonal SAE right handed coordinate system Acceleration 1s positive when it is oriented towards the positive side of the coordinate axis For example with a DMU380ZA Series product sitting on a level table it will measure zero g along the x and y axes and 1 g along the z axis Normal Force acceleration is directed upward and thus will be defined as negative for the DMU380ZA Series z axis The angular rate sensors are aligned with these same axes The rate sensors measure angular rotation rate around a given axis The rate measurements are labeled by the appropriate axis The direction of a positive rotation is defined by the right hand rule With the thumb of your right hand pointing along the axis in a positive direction your fingers curl around in the positive rotation direction For example if the DMU380ZA Series product is sitting on a level surface and you rotate it clockwise on that surface this will be a positive rotation around the z axis The x and y axis rate sensors would measure zero angular rates and the z axis sensor would measure a positive angular rate The magnetic sensors are aligned with the same axes definitions and sign as the linear acceleromete
98. ic condition is met to allow for an algorithm restart The quasi static condition required is that the absolute value of each low passed rate sensor fall below 3 deg sec to begin initialization The system will then attempt a normal algorithm start Dynamic The default setting is ON for the INS380ZA Turning off the dynamic motion setting Motion results in a higher gain state that uses the accelerometer feedback heavily During periods of time when there is known low dynamic acceleration this switch can be turned off to allow the attitude estimate to quickly stabilize threshold the feedback gains from the accelerometer signals for attitude correction are reduced because they are likely corrupted 3 9 3 INS380ZA Built In Test As with the IMU VG and AHRS380ZA the Built In Test capability allows users of the INS380ZA to monitor health diagnostic and system status information of the unit in Turn Switch 0 5 With respect to centripetal or false gravity forces from turning dynamics or coordinated threshold deg sec turn the INS380ZA monitors the yaw rate If the yaw rate exceeds a given Turnswitch Doc 7430 3810 Rev 02 Page 26 DMU380ZA Series User s Manual MEMSIC real time The Built In Test information consists of a BIT word 2 bytes transmitted in every measurement packet In addition there 1s a diagnostic packet TO that can be requested via the Get Packet GP command which contains a complete set of status for each
99. iguration Field Modify Current Value Value to Set 57600 baud M Packet Type m 100 Hz X Y Z jeux MET y Hz Baud Rate D Packet Rate p Orientation yz tUX Ys GPS Baud Rate E 38400 baud Novatel binary GPS Protocol a Get All Values Auto baud v fauto detect v Set Values Temporary reset after reboot C Permanant saved after reboot Figure 24 Unit Configuration Advanced Configuration Users who wish to access some of the more advanced features of NAV VIEW and the DMU380ZA Series products can do so by selecting the Advanced tab at the top of the Unit Configuration window N WARNING Users are strongly encouraged to read and thoroughly understand the consequences of altering the settings in the Advanced tab before making changes to the unit configuration These settings are discussed in detail in Chapter 4 below Behavior switches are identified at the top of the page with marked boxes A blue box will appear if a switch has been enabled similar to Figure 25 below The values can be set in the same manner as noted in the previous section To set a value users select the appropriate Modify checkbox on the left side of the menu and select or enable the appropriate value they wish to set At the bottom of the page users have the option of Dock 7430 3810 Rev 02 Page 86 DMU380ZA Series User s Manual MEMSIC temporarily or permanently setting v
100. imary reliance on angular rate sensors This situation is indicated by the softwareStatus gt turnSwitch status flag Using the turn switch maintains better attitude accuracy during short term dynamic situations but care must be taken to ensure that the duty cycle of the turn switch generally stays below 10 during the vehicle mission A high turn switch duty cycle does not allow the system to apply enough rate sensor bias correction and could allow the attitude estimate to become unstable The VG380ZA algorithm has two major phases of operation The first phase of operation is the initialization phase During the initialization phase the VG380ZA is expected to be stationary or quasi static so the EKF weights the accelerometer gravity reference heavily in order to rapidly estimate the roll and pitch angles and X Y rate sensor bias The initialization phase lasts approximately 60 seconds and the initialization phase can be monitored in the softwareStatus BIT transmitted by default in each measurement packet After the initialization phase the VG380ZA operates with lower levels of feedback also referred to as EKF gain from the accelerometers to continuously estimate and correct for roll and pitch errors as well as to estimate X and Y rate sensor bias Dock 7430 3810 Rev 02 Page 15 DMU380ZA Series User s Manual MEMSIC If a user wants to reset the algorithm or re enter the initialization phase sending the algorithm reset command AR wil
101. inertial system to the user system as a result of a poll request or a continuous packet output setting Input messages are sent from the user system to the DMU380ZA Series inertial system and will result in an associated Reply Message or NAK message Note that reply messages typically have the same 2 byte packet type U2 gt as the input message that evoked it but with a different payload Table 33 Message Table ASCII Mnemonic 2 byte payload Description Type Products packet byte length Available type U2 gt U1 gt x mr gge and Response Message em AN and Response Message Interactive Commands ge a e e Oo Doc 7430 3810 Rev 02 Page 48 DMU380ZA Series User s Manual MEMSIC Request Message Algorithm Reset Input Reply VG AHRS INS Message Error Response Reply Message Calibrate Input Reply Command and Message Response Calibration Reply AHRS INS Completed Message Identification Data Output Message Version Data Output Message 28 Test 0 Detailed Output BIT o Status Message Scaled Sensor 0 Output IMU380ZA Data Message 209 409 a E Scaled Sensor 1 Output Data Message Angle 1 Data Output AHRS INS Message Angle 2 Data Output VG AHRS Message INS Nav 0 Data Output VG AHRS Message INS Nav 1 Data Output VG AHRS Message INS Short Packet Output OEM Only Angle B1 Data Message Short Packet Output OEM Only B2 Data Message 0x5746 numFields 4 MEE Fields Input 1 Request
102. ion level can be high and it can prove helpful to filter accelerometers Freely The Freely Integrate setting allows a user to turn the AHRS380ZA into a free gyro In Integrate free gyro mode the roll pitch and yaw are computed exclusively from angular rate with no kalman filter based corrections of roll pitch or yaw When turned on there is no coupling of acceleration based signals into the roll and pitch or magnetometer based signals to the yaw As a result the roll pitch and yaw outputs will drift roughly linearly with time due to sensor bias For best performance the Freely Integrate mode should be used after the algorithm has initialized This allows the Kalman Filter to estimate the roll and pitch rate sensor bias prior to entering the free gyro mode Upon exiting the free gyro mode OFF one of two behaviors will occur 1 If the AHRS380ZA has been in freely integrate mode for less than sixty seconds the algorithm will resume operation at normal gain settings 2 If the AHRS380ZA has been in freely integrate mode for greater than sixty seconds the algorithm will force a reset and reinitialize with high gains automatically The Use Mags setting allows users to turn on and off the magnetometer feedback for yaw heading stabilization The default setting is ON for the AHRS380ZA When Use Mags is turned ON the AHRS380ZA uses the magnetic field sensor readings to stabilize the drift in yaw and it slaves the yaw to the compass rea
103. is fed into a high speed 200Hz signal processing chain These 6 DOF signals pass through one or more of the processing blocks and these signals are converted into output measurement data as shown Measurement data packets are available at fixed continuous output rates or on a polled basis The type of measurement data packets available depends on the unit type according to the software block diagram and Table 5 Aiding sensor data is used by an Extended Kalman Filter EKF for drift correction in the INS AHRS and VG Series products Built In Test and Status data is available in the measurement packet or via the special Status Packet TO As shown in the software block diagram the DMU380ZA Series has a unit setting and profile block which configures the algorithm to user and application specific needs This feature is one of the more powerful features in the DMU380ZA Series architecture as it allows the DMU380ZA Series to work in a wide range of commercial applications by settings different modes of operation for the DMU380ZA Series Dock 7430 3810 Rev 02 Page 9 DMU380ZA Series User s Manual MEMSIC E Measurement IMU Scaled Pack a B caled Packets VG AHRS Angle INS Nav Packets g Data Available to S0 S1 Packets NO N1 E 5 User Fixed Rate All Units A1 A2 INS AHRS VG a g O Polled INS AHRS VG IMU INS AHRS VG BEB BBB RRR E Ra m m E HEEMENHEHEHHEHNEHENHEEN BEEBE EE BEEBE BEB BeBe am E 6 DOF Sensor Cluster E Wa
104. isting IMU systems Table 2 DMU380ZA Series Feature Description IMU380ZA 200 209 409 6 DOF Digital IMU 9 DOF Digital IMU Standard Range 9 DOF Digital IMU High Range VG380ZA 200 400 6 DOF IMU plus Roll and Pitch Standard Range High Range AHRS380ZA 200 400 9 DOF IMU 3 Axis Internal Magnetometer plus Roll Pitch and Heading Standard Range High Range INS380ZA 200 400 9 DOF IMU 3 Axis Internal Magnetometer with interface for External GPS Receiver plus Position Velocity Roll Pitch and Heading Standard Range High Range The DMU380ZA Series is MEMSIC s fourth generation of MEMS based Inertial Systems building on over a decade of field experience and encompassing thousands of deployed units and millions of operational hours in a wide range of land marine airborne and instrumentation applications It is designed for OEM applications At the core of the DMU380ZA Series is a rugged 6 DOF Degrees of Freedom MEMS inertial sensor cluster that is common across all members of the DMU380ZA Series The 6 DOF MEMS inertial sensor cluster includes three axes of MEMS angular rate sensing and three axes of MEMS linear acceleration sensing These sensors are based on rugged field proven silicon bulk micromachining technology Each sensor within the cluster 1s individually factory calibrated for temperature and non linearity effects during MEMSIC s manufacturing and test process using automated thermal chambers and rate
105. l communications to and from the unit are packets that start with a single word alternating bit preamble 0x5555 This 1s the ASCII string UU e All multiple byte values are transmitted Big Endian Most Significant Byte First e All communication packets end with a single word CRC 2 bytes CRC s are calculated on all packet bytes excluding the preamble and CRC itself Input packets with incorrect CRC s will be ignored e Each complete communication packet must be transmitted to the DMU380ZA Series inertial system within a 4 second period 6 2 Number Formats Number Format Conventions include e xasa prefix to hexadecimal values e single quotes to delimit ASCII characters e no prefix or delimiters to specify decimal values Table 32 defines number formats Table 32 Number Formats Size bytes Unsigned Char tS oba Unsigned Shot 2 010 65535 Unsigned int 4 0t29221 Signed Short 2 s Complement 2 15 to 2 15 1 Dock 7430 3810 Rev 02 Page 46 DMU380ZA Series User s Manual MEMSIC gt Signed Short Shifted 2 s Complement Shifted to specified range Signed Int 2 s Complement 2431 to 2431 1 F4 Floating Point 4 IEEE 54 Single 1 2 127 to 2 127 Precision ASCII MEE 6 3 Packet Format All of the Input and Output packets except the Ping command conform to the following structure 0x5555 2 byte packet type payload byte length variable length lt 2 byte CRC U2 g
106. l force the algorithm into the reset phase The VG380ZA outputs digital measurement data over the UART port at a selectable fixed rate 100 50 25 20 10 5 or 2 Hz or on as requested basis using the GP Get Packet command In addition to the scaled sensor packets described in the IMU380ZA section the VG380ZA has additional measurement output packets including the default A Angle Packet which outputs the roll angle pitch angle and digital IMU data NO and NI packets are also available for use with an external GPS receiver See Section 6 and 7 of the manual for full packet descriptions All data is also available on the SPI output port registers Please refer to section 5 for a complete description of the SPI port functionality 3 3 1 VG380ZA Advanced Settings In addition to the configurable baud rate packet rate axis orientation and sensor low pass filter settings the VG380ZA provides additional advanced settings which are selectable for tailoring the VG380ZA to a specific application requirements These VG380ZA advanced settings are shown in Table 8 below Table 8 VG380ZA Series Advanced Settings Baud Rate 38 400 9600 19200 57600 also available baud Packet Type S1 NO N1 also available Packet Rate 25Hz This setting sets the rate at which selected Packet Type packets are output If polled mode is desired then select Quiet If Quiet is selected the VG380ZA will only send measurement packets in response to G
107. lized This allows the Kalman Filter to estimate the roll and pitch rate sensor bias prior to entering the free gyro mode Upon exiting the free gyro mode OFF one of two behaviors will occur 1 If the VG380ZA has been in freely integrate mode for less than sixty seconds the algorithm will resume operation at normal gain settings 2 If the VG380ZA has been in freely integrate mode for greater than sixty seconds the algorithm will force a reset and reinitialize with high gains automatically Restart On This setting forces an algorithm reset when a sensor over range occurs i e a rotational Over Range rate on any of the three axes exceeds the maximum range The default setting is OFF for the VG380ZA Algorithm reset returns the VG380ZA to a high gain state where the VG380ZA rapidly estimates the gyro bias and uses the accelerometer feedback heavily This setting is recommended when the source of over range is likely to be sustained and potentially much greater than the rate sensor operating limit Large and sustained angular Dock 7430 3810 Rev 02 Page 16 DMU380ZA Series User s Manual MEMSIC rate over ranges result in unrecoverable errors in roll and pitch outputs An unrecoverable error is one where the EKF can not stabilize the resulting roll and pitch reading If the over ranges are expected to be of short duration 1 sec and a modest percentage over the maximum operating range it is recommended that the restart on over ra
108. n a log file 1 To playback data select Playback Mode from the Data Source drop down Data Source LIVE Mode From DMU LIVE Mode from DIL Playback Mode from File 2 Selecting Playback mode will open a text prompt which will allow users to specify the location of the file they wish to play back AII three file formats are supported Engineering Hex and Raw for playback In addition each time recording is stopped started a new section 1s created These sections can be individually played back by using the drop down menu and associated VCR controls menu at the top 3 Once the file is selected users can utilize the VCR style controls at the top of the page to start stop and pause the playback of the data 4 NAV VIEW also provides users with the ability to alter the start time for data __ playback Using the slide bar at the top of the page users can adjust the starting time Raw Data Console NAV VIEW offers some unique debugging tools that may assist programmers in the development process One such tool 1s the Raw Data Console From the View drop down menu simply select the Raw Data Console This console provides users with a simple display of the packets that have been transmitted to the unit Tx and the messages received Rx An example is provided in Figure 21 Doc 7430 3810 Rev 02 Page 83 DMU380ZA Series User s Manual MEMSIC Raw Data Console Tx 5555 504b 00 9ef4 5
109. nd this packet in response to a ping command 7 1 3 Echo Command Echo CH 0x4348 Packet Type Length Payload 0x5555 0x4348 lt echo payload gt lt CRC U2 gt The echo command allows testing and verification of the communication link The unit will respond with an echo response containing the echo data The echo data is N bytes long 7 1 4 Echo Response Echo Payload Contents Scaling Unis 0 eps Ui Webyeofedodia 1 echoData Ui Second byte of echo data Do Qu hota N2 Jechobaa Ut Sewdtksbyeoedo da Na echoData ui iastbyeciechoda 7 2 Interactive Commands Interactive commands are used to interactively request data from the DMU380ZA Series and to calibrate or reset the DMU380ZA Series 7 2 1 Get Packet Request Get Packet GP 0x4750 Packet Type Length Payload 0x5555 0x4750 lt GP payload gt lt CRC U2 gt Doc 7430 3810 Rev 02 Page 51 DMU380ZA Series User s Manual MEMSIC gt This command allows the user to poll for both measurement packets and special purpose output packets including TO VR and ID GP Payload Contents Byte Offset Po requestedPacketType e popo The requested packet type Refer to the sections below for Packet Definitions sent in response to the GP command 7 2 2 Algorithm Reset Command Algorithm Reset AR 0x4152 Packet Type Length Payload 0x5555 0x4152 o
110. nd use a ground plane Route the GPS Antenna RF cable away from sources of radiated energy 1 e switching power supplies 2 1 5 Reserved Factory Use Only During normal operation of the DMU380ZA no connection is made to the Reserved factory use only pins These pins have internal pull up mechanisms and must have no connections for the DMU380ZA to operate properly 2 2 Mechanical Interface The DMU380ZA mechanical interface 1s defined by the outline drawing in Figure 2 Dock 7430 3810 Rev 02 Page 6 DMU380ZA Series User s Manual MEMSIC gt i 4X 2 50 THRU 40 37 70 PIN 20 2 30 9 50 2 54 Figure 2 DMU380ZA Outline Drawing NOTES UNLESS OTHERWISE STATED 1 MATING CONNECTOR SAMTEC CLM 110 02 2 DIMENSION TO CENTROID OF PIN ONE 3 Theory of Operation This section of the manual covers detailed theory of operation for each member of the DMU380ZA Series starting with the basic IMU380ZA and then reviewing each major variant VG AHRS and INS with their associated additional features outputs and performance Table 5 shows the basic features of each member of the DMU380ZA Series with cross references to important sections for review Table 5 DMU380ZA Series Overview Poder ras immi IMU380ZA 6 DOF IMU 9 DOF IMU Read 3 1 and 3 2 VG380ZA 6 DOF IMU Read 3 1 3 2 and 3 3 Roll Pitch AHRS380ZA 9 DOF IMU 3 Axis Internal Magnetometer Read 3 1 3 2 3 3 and 3 4 Doc 7430 3810 Rev 02 Page 7
111. nds Rewa us qua S 9 12 hardwareStatus Field The hardwareStatus field contains flags that indicate various Internal hardware conditions and alerts that are not errors or problems See Table 51 The hardwareStatus flag in the BITstatus field is the bit wise OR of the logical AND of the hardwareStatus field and the hardwareStatusEnable field The hardwareStatusEnable field 1s a bit mask that allows the user to select items of interest that will logically flow up to the masterStatus flag Table 51 DMU380 Hardware Status BIT Field hardwareStatusField Bits Meaning O Z O o o unlocked1PPS 0 O not asserted 1 asserted unlockedInternalGPS 0 not asserted 1 asserted noDGPS 0 DGPS lock 1 no DGPS unlockedEEPROM O locked WE disabled 1 unlocked WE enabled Reserved Doc 7430 3810 Rev 02 Page 76 DMU380ZA Series User s Manual MEMSIC gt 9 13 comStatus Field The comStatus field contains flags that indicate various external communication conditions and alerts that are not errors or problems See Table 52 The comStatus flag in the BITstatus field is the bit wise OR of the logical AND of the comStatus field and the comStatusEnable field The comStatusEnable field is a bit mask that allows the user to select items of interest that will logically flow up to the masterStatus flag Table 52 DMU380 COM Status BIT Field comStatus Field Bits Meaning S noExternalGPS 0 external GPS data is being received 1 no extern
112. nge setting be turned off Handling of an inertial rate sensor over range is controlled using the restartOnOverRange switch If this switch is off the system will flag the overRange status flag and continue to operate through it If this switch is on the system will flag a masterFail error during an over range condition and continue to operate with this flag until a quasi static condition is met to allow for an algorithm restart The quasi static condition required is that the absolute value of each low passed rate sensor fall below 3 deg sec to begin initialization The system will then attempt a normal algorithm start Dynamic The default setting is ON for the VG380ZA Turning off the dynamic motion setting results Motion in a higher gain state that uses the accelerometer feedback heavily During periods of time when there is known low dynamic acceleration this switch can be turned off to allow the attitude estimate to quickly stabilize Turn Switch 10 0 With respect to centripetal or false gravity forces from turning dynamics or coordinated threshold deg sec turn the VG380ZA monitors the yaw rate If the yaw rate exceeds a given Turnswitch threshold the feedback gains from the accelerometer signals for attitude correction are reduced because they are likely corrupted o 84832 0000000 4 3 2 VG380Z4A Built In Test As with the IMU380ZA the VG380ZA Built In Test capability allows users of the VG380ZA to monitor health diagnostic and
113. ntainer 10 3 4 Marking Please write the words FRAGILE DELICATE INSTRUMENT in several places on the outside of the shipping container s In all correspondence please refer to the equipment by the model number the serial number and the RMA number 10 3 5 Return Shipping Address Use the following address for all returned products MEMSIC Inc 1759 McCarthy Blvd Milpitas CA 95035 Attn RMA Number XXXXXX 10 4 Warranty The MEMSIC product warranty 1s one year from date of shipment Doc 7430 3810 Rev 02 Page 80 DMU380ZA Series User s Manual MEMSIC gt Appendix A Installation and Operation of NAV VIEW NAV VIEW has been completely redesigned to allow users to control all aspects of the DMU380ZA Series operation including data recording configuration and data transfer For the first time you will be able to control the orientation of the unit sampling rate packet type hard iron calibration and filter settings through NAV VIEW NAV VIEW Computer Requirements The following are minimum requirements for the installation of the NAV VIEW Software e CPU Pentium class 1 5GHz minimum e RAM Memory 500MB minimum 1GB recommended e Hard Drive Free Memory 20MB e Operating System Windows 2000 or XPTM e Properly installed Microsoft NET 2 0 or higher Install NAV VIEW To install NAV VIEW onto your computer 1 Insert the CD Inertial Systems Product Support Part No 8160 0063 in the CD ROM drive
114. number of satellites in use and the resulting HDOP age of differential data if in use etc SGPGGA hhmmss ss Latitude N Longitude E FS NoSV HDOP msl m Altref m DiffAge DiffStation cs lt CR gt lt LF gt E T GPGGA string Latitude dddmm mmmm a character E dddmm mmmm E character zu m character m Description Message ID GGA protocol header UTC Time Current time Latitude Degrees minutes N S Indicator N north or S south Longitude Degrees minutes E W indicator E east or W west Position Fix Indicator See Table below Satellites Used Range 0 to 12 O Bas O HA Co N NX Co a NO G co e Se C gt a co S co ce HDOP Horizontal Dilution of Precision MSL Altitude m Units Meters fixed field Geoid Separation m Units Meters fixed field el 2 ele 2al 2a l 2 D D o 3 3 3 3 D D AE D D D 5 E EY DA O O O O O Age of Differential Corrections sec Blank Null fields when DGPS is not used Diff Reference Station ID Checksum DiffAge DiffStation E NNNM Doc 7430 3810 Rev 02 Page 93 p C1 UJ DMU380ZA Series User s Manual MEMSIC gt peer pein Doc 7430 3810 Rev 02 Page 94 DMU380ZA Series User s Manual MEMSIC gt Appendix C Sample Packet Parser Code Overview This appendix includes sample code written in ANSI C for parsing packets from data sent by the DMU380ZA Series Inertial Sy
115. or the accelerometers and 20Hz for the accels angular rate sensors There is one filter setting for all three angular rate sensors There is 20 H one filter setting for all three accelerometer sensors The reason for filtering the ales accelerometers IS that in many installations the vibration level can be high and it can prove helpful to filter accelerometers Freely Integrate The Freely Integrate setting allows a user to turn the INS380ZA into a free gyro In free gyro mode the roll pitch and yaw are computed exclusively from angular rate with no kalman filter based corrections of roll pitch and yaw When turned on there is no coupling of acceleration based signals into the roll and pitch or magnetometer based signal to the yaw As a result the roll pitch and yaw outputs will drift roughly linearly with time due to sensor bias For best performance the Freely Integrate mode should be used after the algorithm has initialized This allows the Kalman Filter to estimate the roll and pitch rate sensor bias prior to entering the free gyro mode Upon exiting the free gyro mode OFF one of two behaviors will occur 1 Ifthe INS380ZA has been in freely integrate mode for less than sixty seconds Doc 7430 3810 Rev 02 Page 25 DMU380ZA Series User s Manual MEMSIC the algorithm will resume operation at normal gain settings If the INS380ZA has been in freely integrate mode for greater than sixty seconds the algorithm will force a
116. ors in roll and pitch outputs An unrecoverable error is one where the EKF can not stabilize the resulting roll and pitch reading If the over ranges are expected to be of short duration 1 sec and a modest percentage over the maximum operating range it is recommended that the restart on over range setting be turned off Handling of an inertial rate sensor over range is controlled using the restartOnOverRange switch If this switch is off the system will flag the overRange status flag and continue to operate through it If this switch is on the system will flag a masterFail error during an over range condition and continue to operate with this flag until a quasi static condition is met to allow for an algorithm restart The quasi static condition required is that the absolute value of each low passed rate sensor fall below 3 deg sec to begin initialization The system will then attempt a normal algorithm start Dynamic ON The default setting is ON for the AHRS380ZA Turning off the dynamic motion setting Motion results in a higher gain state that uses the accelerometer feedback heavily During periods of time when there is known low dynamic acceleration this switch can be turned off to allow the attitude estimate to quickly stabilize threshold threshold the feedback gains from the accelerometer signals for attitude correction are reduced because they are likely corrupted 3 4 3 AHRS380ZA Built In Test As with the IMU380ZA and VG380Z4A t
117. p 200 216 X rate temperature yRateTemp 200 246 Y rate temperature I zRateTemp TEE 200 2 16 Z rate temperature boardTemp 200 2 16 des C CPU board temperature 20 Counter U2 packets Output packet counter 122 BlTstatus E E Master BIT and Status 7 4 3 Angle Data Packet 1 Default AHRS Data Angle Data A1 0x4131 Packet Type Length Payload 0x5555 0x4131 A1 payload CRC U2 gt This packet contains angle data and selected sensor data scaled in most cases to a signed 2 16 2 s complement number Data involving angular measurements include the factor pi in the scaling and can be interpreted in either radians or degrees Angles scaled to a range of p1 p1 or 180 deg to 180 deg Angular rates scaled to range of 3 5 pi pi or 630 deg sec to 630 deg sec Accelerometers scaled to a range of 10 10 g Magnetometers scaled to a range of 10 10 Gauss Temperature scaled to a range of 100 100 C Doc 7430 3810 Rev 02 Page 57 DMU380ZA Series User s Manual MEMSIC gt A1 Payload Contents Byte Offset rollAngle 2 2 pi 2 16 Radians Roll angle 3607 2 16 2 pitchAngle l2 2 pi 2 16 Radians Pitch angle 360 2 16 4 yawAngleMag 12 2 pi 2 16 Radians Yaw angle magnetic 360 2 16 north xRateCorrected 12 7 pi 2 16 rad s X angular rate Corrected yRateCorrected T pi 2 16 rad s Y angular rate Corrected zRateCorrected 7 pi 2 16 rad s Z angular rate Corrected 12607
118. put If polled mode is desired then select Quiet If Quiet is selected the IMU380ZA will only send measurement packets in response to GP commands Orientation See Figure 6 To configure the axis orientation select the desired measurement for each and Figure 7 axis NAV VIEW will show the corresponding image of the IMU380ZA so it easy to visualize the mode of operation Refer to Section 8 4 Orientation Field settings for the twenty four possible orientation settings Filter Settings 5 The low pass filters are set to a default of 20 Hz for the accelerometers and 20 10 20 50 Hz Hz for the angular rate sensors There is one filter setting for all three angular rate sensors There is one filter setting for all three accelerometers m o E T NOTE on Filter Settings Why change the filter settings Generally there is no reason to change the low pass filter settings on the IMU380ZA or other DMU380ZA Series Inertial Systems However when a DMU380ZA Series product is installed in an environment with a lot of vibration it can be helpful to reduce the vibration based signal energy and noise prior to further processing on the signal Installing the IMU380ZA in the target environment and reviewing the data with NAV VIEW can be helpful to determine if changing the filter settings would be helpful Although the filter settings can be helpful in reducing vibration based noise in the signal low filter settings e g 5Hz also reduce the bandwidth of
119. raft which requires banking A turn switch threshold that is too low may cause turn switch activation with high duty cycle causing random walk in roll and pitch angles due to low feedback gains A cutoff frequency must be far away from major frequency components caused by the rotor vibration 44 Land Vehicle Some examples of land vehicles are Automobiles trucks heavy equipment trains snowmobiles and other tracked vehicles Table 16 provides the recommended advanced settings for two different types of application Doc 7430 3810 Rev 02 Page 29 DMU380ZA Series User s Manual MEMSIC Table 16 Recommended Advanced Settings for Land Vehicle Recommended Product VG380ZA or INS380ZA Dynamic Condition Recommended Settings Heavy Equipment Application Automotive Testing IMU and VG default EE ERE E Do poa yo UseGPS Restart Over Range Dynamic Motion Turn Switch Threshold 5 0 deg s 10 0 deg s Z Filter Accel Hz Hz When not in distorted magnetic environment 45 Water Vehicle Water vehicle is a craft or vessel designed to float on or submerge and provide transport over and under water Table 17 provides the recommended advanced settings for two different types of application Table 17 Recommended Advanced Settings for Water Vehicle Recommended Product INS380ZA Application Recommended Settings ON ON UseMags UseGPS Freelntegrate Restart Over Range Dynamic Motion ON ON Z Filter Accel
120. reading the queue looking for packets A separate process might add data to this queue when it arrives It is up to the user to ensure circular queue integrity by using some sort of mutual exclusion mechanism withing the queue access funtions Doc 7430 3810 Rev 02 Page 95 DMU380ZA Series User s Manual Code listing include lt stdio h gt buffer size define MAXQUEUE 500 Pe circular queue TP typedef struct queue tag int count int front int rear char entry MAXQUEUE QUEUE TYPE MEMSIC packet ur typedef struct xbow packet unsigned short packet type char Length unsigned short crc char data 256 XBOW PACKET QUEUE TYPE Cire Dur MEMSIC KKK KR KKK KKK KK KK Ck KK KK RK KK kk KK KKK kk KKK Ck KC kk Ck Ck kk ck k ck ck ck k ck ck k ck ck ck k ck ck k kc kck k kk k FUNCTION process xbow packet looks for packets in a queue ARGUMENTS queue ptr 1 pointer to queue to process result will contain the parsed info when return value is 1 RETURNS O when failed m 1 when successful KKK ck k kk kk k ck kk ck ck kk Ck kk ck ck k kk ck k ck ck k kk ck k kc k ck k ck ck kk Ck ck k kc k kk ck ck k kc k ck k ck ck kk ck ck k ck ck k ck kck k kck kk kk int process xbow packet QUEUE TYPE queue ptr XBOW PACKET result unsigned short myCRC 0 packetCRC counter 0 0 packet type D numToPop 0 char packet 100 tempchar dataLength if Empty queue ptr
121. ree axis magnetic field sensor to be calibrated while installed in its operating environment See section 3 4 1 for information and tips regarding installation and calibration and why magnetic calibration is necessary Please review this section of the manual before proceeding to use the INS380ZA 3 5 2 INS380ZA Advanced Settings In addition to the configurable baud rate packet rate axis orientation and sensor low pass filter settings the INS380ZA provides additional advanced settings which are selectable for tailoring the INS380ZA to a specific application requirements The INS380ZA advanced settings are shown in Table 12 below Table 12 INS380ZA Series Advanced Settings Default Comments Baud Rate 38 400 9600 19200 57600 also available baud Packet Type 90 1 A1 A2 NO also available Packet Rate 25 Hz This setting sets the rate at which selected Packet Type packets are output If polled mode is desired then select Quiet If Quiet is selected the INS380ZA will only send measurement packets in response to GP commands Orientation To configure the axis orientation select the desired measurement for each axes NAV VIEW will show the corresponding image of the INS380ZA so it easy to visualize the mode of operation See section 8 4 Orientation Field settings for the twenty four possible orientation settings The default setting points the connector AFT Filter Settings 20 Hz The low pass filters are set to a default of 20Hz f
122. registers Table 20 lists the data contained in a standard packet along with the corresponding registers The registers are listed in the order in which they are sent during a burst mode read Doc 7430 3810 Rev 02 Page 35 DMU380ZA Series User s Manual MEMSIC Table 20 DMU380ZA Burst Mode Output Registers Register Name Register Address STATUS eR X RATE Rate Sensor Output X Axis Y RATE Rate Sensor Output Y Axis Z RATE Rate Sensor Output Z Axis X ACCEL Accelerometer Output X Axis Y ACCEL Accelerometer Output Y Axis Z ACCEL Accelerometer Output Z Axis Burst mode begins when the master requests a read from a burst mode data packet 1 e Ox3E Eight additional SPI cycles complete the read one for each word in the standard data packet Figure 11 illustrates the burst mode sequence Note if the incorrect number of SPI cycles follow the burst mode command the SPI transfer will either complete early or remain in burst mode subsequent reads writes will be out of sync with the SPI transfer cycle of the DMU380ZA nSs ax A M m BOARD MISO TEMP Figure 11 Multiple Register Read via Burst Mode Operational notes 1 When combining polled and burst reads use only single register polled reads 2 Burst mode reads for other data packets are performed in a manner similar to the standard packet The only deviation from the method described above is the register address
123. reset and reinitialize with high gains automatically The Use GPS setting allows users to turn on and off the GPS feedback The default setting is ON for the INS380ZA When Use GPS is turned OFF the INS380ZA s behavior will revert to that of an AHRS380ZA See the AHRS380ZA Theory of Operation for detailed description Stationary Yaw This setting defaults to OFF on the INS380ZA and it is recommended to be OFF for the Lock INS380ZA The stationary yaw lock setting is only recommended for consideration when the INS380ZA is operating with GPS Use GPS ON and WITHOUT magnetometer feedback Use Mags OFF Stationary yaw lock may be appropriate if the user platform is a wheeled land vehicle The Use Mags setting allows users to turn on and off the magnetometer feedback for yaw heading stabilization The default setting is ON for the INS380ZA When Use Mags is turned ON the INS380ZA uses the magnetic field sensor readings to stabilize the drift in yaw and it slaves the yaw to the compass reading provided from the magnetic field sensor readings When UseMags is turned OFF the heading yaw angle measurement of the INS380ZA will be slaved to the GPS heading if GPS is available otherwise the heading will drift feely The reason for this setting is to give the user an ability to turn off the magnetometer stabilization when severe magnetic distortion may be occurring This setting is desirable when the user vehicle temporarily moves in close proximity
124. rs For example when oriented towards magnetic North you will read approximately 0 25 Gauss along X 0 0 Gauss along Y and 40 35 Gauss along Z direction North America Magnetic values at other geographic locations can be found at http www ngdc noaa gov seg WMM DoDWMM shtml Pitch is defined positive for a positive rotation around the y axis pitch up Roll is defined as positive for a positive rotation around the x axis roll right Yaw is defined as positive for a positive rotation around the z axis turn right The angles are defined as standard Euler angles using a 3 2 1 system To rotate from the body frame to an earth level frame roll first then pitch and then yaw The position output from GPS 1s represented in Latitude Longitude and Altitude LLA convention on the WGS84 Ellipsoid This 1s the most commonly used spherical coordinate system The GPS velocity is defined in North East and Down reference frame The users can convert this into Cartesian coordinate system called Earth Centered Earth Fixed ECEF ECEF uses three dimensional XYZ coordinates in meters to describe the location of a GPS user or satellite Several online resources are available to help users with this transformation For example refer to the application note on MEMSIC website http www memsic com support documentation inertial systems category 3 application notes html 3 1 1 Advanced Settings The DMU380ZA Series Inertial Systems have a numb
125. rsion factor 4000 LSB g default Z ACCEL OxOE X MAG 0x10 Y MAG 0x12 Z MAG Rate sensor temperature information twos complement format conversion Tout C Vout 0 7311 C LSB 31 0 C System temperature information twos complement format conversion Tout C Vout 0 7311 C LSB 31 0 C 5 4 System Registers In addition to the output data registers there are further read only registers that provide DMUS380ZA system information to the SPI master Table 22 provides a description of each along with their read addresses X Y Z axis magnetometer information twos complement format conversion factor 16000 LSB G default Table 22 DMU380ZA System Registers Read Address DIAGNOSTIC STATUS sensor self test and over range information See Section 5 5 T o Results of the magnetic alignment procedure see Section 5 7 4 Ox4E Doc 7430 3810 Rev 02 Page 37 DMU380ZA Series User s Manual MEMSIC COMM MASTER See Section 9 6 Com BIT Field COMM DATA STATUS See Section 9 13 Com Status Field COMM BUS A See Section 9 7 Com Serial A BIT Field COMM BUS B See Section 9 8 Com Serial B BIT Field SENSOR STATUS see Section 9 15 Sensor Status Field 5 5 Diagnostic Status Register The diagnostic status register contains information describing the results of the self test as well as sensor over range information It is defined in Table 23 Table 23 Diagnostic Status Register Base Address
126. rt signals which has been enabled See Section 9 Advanced BIT for details on configuring the masterStatus flags Table 11 shows the BIT definition and default settings for BIT programmable alerts in the AHRS380ZA Dock 7430 3810 Rev 02 Page 22 DMU380ZA Series User s Manual MEMSIC Table 11 AHRS380ZA Default BIT Status Definitions softwareError O normal 1 internal software error or BIT magAlignOutofBounds mo Reserved 4 masterStatus softwareStatus 1 0 nominal 1 Algorithm Initialization or High Gain Reserved 13 15 N A BEEN The AHRS380ZA also allows a user to configure the Status byte within the BIT message To configure the word select the BIT Configuration tab from the Unit Configuration menu The dialog box allows selection of which status types to enable hardware software sensor and comm Like the VG380ZA and IMU380ZA MEMSIC recommends for the vast majority of users that the default Status byte for the AHRS380ZA 1s sufficient For users who wish to have additional visibility to when the AHRS380ZA EFK algorithm estimates that the AHRS380ZA is turning about its Z or Yaw axis the softwareStatus bit can be configured to go high during a turn In other words the turnSwitch will turn on the softwareStatus bit In the AHRS380ZA the turnSwitch is by default set at 0 5 deg sec about the Z axis 3 5 INS380ZA Theory of Operation The INS380ZA supports all of the features and operating modes of the IMU VG AHRS3
127. rtlett 0x06 6 5 Hz Bartlett default 0x30 48 50 Hz Butterworth 0x40 64 20 Hz Butterworth 0x50 80 10 Hz Butterworth 0x60 96 5 Hz Butterworth The rate sensor scaling selector adjusts the output scaling applied to the rate sensor values in registers 0x04 through 0x08 as well as the values in the standard data packet scaling in the other data packets are not affected Additionally this setting affects the Doc 7430 3810 Rev 02 Page 41 DMU380ZA Series User s Manual MEMSIC gt limits that control the sensor over range bit in the diagnostic status register Table 23 if the system undergoes motion that exceeds this limit the over range bit is set The default scaling is 125 0 sec to change the scaling to 62 5 sec the master sends OxB901 The rate sensor dynamic range selection maps to a bit weight scale factor as defined in Table 28 Table 28 Rate Sensor Scaling Factor Dynamic Range Scale Factor 62 5 sec 400 LSB sec 125 0 sec 200 LSB sec 250 0 sec 100 LSB sec The digital low pass filter register sets the type and cutoff frequency of the filter applied to the scaled sensor data The default setting is a 5 Hz Bartlett filter to switch to a 20 Hz Butterworth filter the master sends OxB840 Figure 14 describes the output response of the different Bartlett filter settings Digital Low Pass Bartlett Filter Response o 1 100 10 20 30 40 50 i ll 60 70
128. s There are three tabs within the Unit Configuration menu General Advanced and BIT Configuration The General tab displays some of the most commonly used settings The Advanced and BIT Configuration menus provide users with more detailed setting information that they can tailor to meet their specific needs To alter a setting simply select the check box on the left of the value that you wish to modify and then select the value using the drop down menu on the right side Once you have selected the appropriate value these settings can be set temporarily or permanently a software reset or power cycle is required for the changes to take affect by selecting from the choices at the bottom of the dialog box Once the settings have been altered a Success box will appear at the bottom of the page gt IMPORTANT Caution must be taken to ensure that the settings selected are compatible with the system that is being configured In most cases a FAIL message will appear if incompatible selections are made by the user however it 1s the users responsibility to ensure proper configuration of the unit Dock 7430 3810 Rev 02 Page 85 DMU380ZA Series User s Manual MEMSIC gt IMPORTANT Unit orientation selections must conform to the right hand coordinate system as noted in Section 3 1 of this user manual Selecting orientations that do not conform to this criteria are not allowed Unit Configuration General Advanced BIT Conf
129. s e or ar eoor aieri eroinei 86 Dit COMM SUM ATION 505 14 desaais anca sacadas E EE EEE 87 Mas Alenaiient ProcedurTe sacas spathasonsinns aa sos densas Ads poo kin DERI iaa aa ieee Ekaia 88 Hard Iron Soft Iron OVetViG Wu rali idas 88 Mag Alignment Procedure Using NAV VIEW ccccccccccccsssssssssssssssseeeeeeeeeseeeeeeaaas 89 REC Doha Oi AO ERR RD PED RR ROD OR EE 91 Page iv Doc 7430 3810 Rev 02 DMUS380ZA Series User s Manual MEMSIC gt Appendix B NMEA Message Format cssssssesssseeeceeeeeececeeeeeanassesseseseeeeceeeeeeeeeeeaaas 93 EIS EON I E ace T ms 93 Appendix C Sample Packei Parser Code uon meet CAdnEaDadoB Le EnuduG canada das edad 95 CO VOICE 95 Code SEO a EET TD TEE 96 Appendix D Sample Packet Decoding cee cecceesesececeeeeeeeeeeeaeaeeeeessseseeeeeeeeeeseeeenaaas 102 Doc 7430 3810 Rev 02 Page v DMU380ZA Series User s Manual MEMSIS gt About this Manual The following annotations have been used to provide additional information 4 NOTE Note provides additional information about the topic M EXAMPLE Examples are given throughout the manual to help the reader understand the terminology gt IMPORTANT This symbol defines items that have significant meaning to the user N WARNING The user should pay particular attention to this symbol It means there 1s a chance that physical harm could happen to either the person or the equipment
130. se ie Petr E an ciue I rona POP REESE DNE Du ERU ds T1 9 14 BOM are atas ENT LEE T T Tm TI 9 15 BE Mis Ol AUIS y Lo RR T P T 9 16 Configuring the Master Status eeeesssssssssssssseeseeeeeee nnne enne T1 9 16 1 hardwareStatusEnable Field cesses eene 78 2 16 72 comsStatusEnable Field eiui tu tei iae opea ier bia evoked aE edo 78 9 16 3 softwareStatusEnable Field esce 78 9 16 4 sensorStatusEnable Field eese eio or rat abeo saure oae a 78 10 Warranty and Support Information esses 79 Des AOI ZAC tI TET 79 10 3 2 Identification and Protection essen 79 WO Seam ACO ODtaltieTssuadurssotoisiec iei rias Eoria 80 LED RS MM EUER T 80 10 3 5 Return Shipping Address eeeeeeessessssssseeeeeeeen nennen enne 80 Appendix A Installation and Operation of NAV VIEW ccccccsssssssssssseeceeeeeeeeeeeeeneas 81 NAV VIEW Computer Requirements sss 81 Hasta NA VV TEM oes 81 oniei im 81 Sen UPNA VIE W E 82 Data CC e RETIRER T MT 82 Pe WAN AG dM um 83 REBEL RR E 83 Horizon and Compass View uossocesnieesespoetns bakotancususse enu re aa ante xu up eue osse EEEE EEE 84 Packer SEIUSUCS VIO st ccc E S 85 IB IR OMT Ui QUOI Roe RR RE USER o oo ET 85 Advanced Conio ur MO esii
131. ser s Manual MEMSIC gt Too Enor RESPONSE NOT Uu 54 T3 EE Od Packets Polled j NER TT 54 Zl Id ntification Data Packet ossueudio tag asda is aa di sec Uc UE 54 T32 Version Data AC CU escien ias asd nda a ra S san tea Sn 54 7 3 3 Test 0 Detailed BIT and Status Packet s cecccceeecceeeeseeeeeeeees 55 7 4 Output Packets Polled or ContinuousS c cccccccccccccccceeessssseseeeeeeceeeeeeeeeeeaaas 55 7 4 1 Scaled Sensor Data Packet O sse eene enne 55 7 4 2 Scaled Sensor Data Packet 1 Default IMU Doata eene 56 7 4 3 Angle Data Packet 1 Default AHRS Data eeeeeeese 57 7 4 4 Angle Data Packet 2 Default VG Data erre 58 des I AA O p 59 7 4 6 Nav Data Packet 1 Default INS Data eeccceeeccseeesceeeeeeees 60 7 4 7 Angle Data Packet BI Custom VG Data eee 61 7 4 8 Angle Data Packet B2 Custom VG Data 62 8 DMU380ZA Advanced UART Port Commands eese 63 Sd Configuration Fields ccesrmpglacotosasisonissusc T riiai iania 63 2 Continuous Packet Type EIL 63 S ADIP IEAL Fier DELHI Soie itenim a E E E EE E 64 o4 Or ntaon PICO eronneen G 64 89 User Behavior Wy Cs EET DITS 66 8 6 Hard and Soft Iron Values eese nnns 66 oJ Headine Track RE TTE ERU 66 8 8 Commands to Program Configuration eeseeesssssseseeeeeeeeeeeee enn 67 Ol Want RI
132. set fields and an error response may be received as a result of one set fields command Attempts to set a field with an invalid value is one way to generate an error response A table of field IDs and valid field values is available in Section 8 1 SF Payload Contents Byte Offset Units 0 num U ooo fd QU 5 freo u uw uw uw E i e fs s ae HN The second field ID s data to set ER E CA E ds 7 field1Data numFields 4 3 field U2 numFields 4 1 field Data U2 The last field ID to set The last field ID s data to set U1 U2 U2 U2 U2 U2 U2 U2 Set Fields Response Set Fields SF 0x5346 Packet Type Length Payload 0x5555 0x5346 1 numFields 2 SF payload CRC U2 gt The unit will send this packet in response to a set fields command if the command has completed without errors SF Payload Contents Byte Offset Units 0 mms Ui __ The number of las sa 1 feld u The second field ID sat e e Mr field IDs set 1 fieldo U2 0 The first field ID set numFields 2 1 Field U2 f Thelastfield ID set Doc 7430 3810 Rev 02 Page 68 DMU380ZA Series User s Manual MEMSIC gt 8 9 Read Fields Command Read Fields RF 0x5246 Packet Type Length Payload 0x5555 0x5246 1 numFields 2 RF payload CRC U2 gt This command allows the user to read the default power up configuration fields from the EEPROM NumFields is the number of
133. stem Output Data Rate 0x00 0 Data output suppressed 0x01 1 200 Hz default 0x02 2 100 Hz 0x03 3 50 Hz 0x04 4 25 Hz 0x05 5 20 Hz 0x06 6 10 Hz 0x07 7 5 Hz 0x08 8 4 Hz 0x09 9 2 Hz 0x10 10 1 Hz Z System Clock 0 External Clock 1 Internal Clock default The ODR enables the master to specify the output rate of data provided by the DMU380ZA Setting this register directly affects the data ready signal The default ODR is 200 Hz to change the ODR to 100 Hz the master sends 0xB702 The system clock setting bit 0 switches between the internal DMU380ZA system clock and the external 1 kHz sync signal To switch to an external clock the master sends OxB600 5 7 3 Rate Sensor Scaling Low Pass Filter The rate sensor scaling and digital low pass filter configuration are combined into a single 16 bit register at memory location 0x38 individual bits are assigned according to Table 27 Note these settings apply only to data output via the DMU380ZA SPI port and do not affect the low level UART output port Table 27 Sensor Scaling Digital Low Pass Filter Register Base Address 0x38 Read Write Description Default 0x0206 m 8 11 Rate Sensor Scaling Dynamic Range Selector 0x1 1 62 5 sec 0x2 2 125 0 sec default 0x4 4 250 0 sec 7 0 Digital Low Pass Filter 0x00 0 Unfiltered 0x03 3 40 Hz Bartlett 0x04 4 20 Hz Bartlett 0x05 5 10 Hz Ba
134. stems This code can be used by a user application reading data directly from the DMU380ZA Series product or perhaps from a log file The sample code contains the actual parser but also several support functions for CRC calculation and circular queue access e process xbow packet for parsing out packets from a queue Returns these fields in structure XBOW_PACKET see below Checks for CRC errors e calcCRC for calculating CRC on packets e Initialize initialize the queue e AddQueue add item in front of queue e DeleteQueue return an item from the queue e peekWord for retrieving 2 bytes from the queue without popping e peekByte for retrieving a byte from the queue without popping e Pop discard item s from queue e Size returns number of items in queue e Empty return 1 if queue is empty O if not e Full return 1 if full O if not full The parser will parse the queue looking for packets Once a packet is found and the CRC checks out the packet s fields are placed in the XBOW PACKET structure The parser will then return to the caller When no packets are found the parser will simply return to the caller with return value O The XBOW PACKET stucture 1s defined as follows typedef struct xbow packet unsigned short packet type char length unsigned short crc char data 256 XBOW PACKET Typically the parser would be called within a loop in a separate process or in some time triggered environment
135. system status information of the unit in real time The Built In Test information consists of a BIT word 2 bytes transmitted in every measurement packet In addition there 1s a diagnostic packet TO that can be requested via the Get Packet GP command which contains a complete set of status for each hardware and software subsystem in the VG380ZA See Sections 6 8 for details on the TO packet The BIT word contained within each measurement packet is detailed below The LSB Least Significant Bit is the Error byte and the MSB Most Significant Bit is a Status byte with programmable alerts Internal health and status are monitored and communicated in both hardware and software The ultimate indication of a fatal problem is the masterFail flag The masterStatus flag is a configurable indication that can be modified by the user This flag is asserted as a result of any asserted alert signals which have been enabled See Advanced BIT Section 9 for details on configuring the masterStatus flags Table 9 shows the BIT definition and default settings for BIT programmable alerts in the VG380ZA Table 9 VG380ZA Default BIT Status Definition Reserved N A EE Doc 7430 3810 Rev 02 Page 17 DMU380ZA Series User s Manual MEMSIS gt softwareStatus 0 nominal 1 Algorithm Initialization or High Gain Status The VG380ZA also allows a user to configure the Status byte within the BIT message To configure the word select the
136. t U2 gt U1 gt payload gt The Ping Command does not require a CRC so a DMU380ZA Series unit can be pinged from a terminal emulator To Ping a DMU380ZA Series unit type the ASCII string UUPR If properly connected the DMU380ZA Series unit will respond with PK All other communications with the DMU380ZA Series unit require the 2 byte CRC Note A DMU380ZA Series unit will also respond to a ping command using the full packet formation with payload O and correctly calculated CRC Example 0x5555504B009ef4 6 3 1 Packet Header The packet header is always the bit pattern 0x5555 6 3 2 Packet Type The packet type is always two bytes long in unsigned short integer format Most input and output packet types can be interpreted as a pair of ASCII characters As a semantic aid consider the following single character acronyms P packet F fields Refers to Fields which are settings or data contained in the unit E EEPROM Refers to factory data stored in EEPROM R read Reads default non volatile fields G get Gets current volatile fields or settings W write Writes default non volatile fields These fields are stored in non volatile memory and determine the unit s behavior on power up Modifying default fields take effect on the next power up and thereafter S set Doc 7430 3810 Rev 02 Page 47 DMU380ZA Series User s Manual MEMSIS gt Sets current volatile fields or settings Modifying current fields
137. ta UZ e e The first field ID s data retrieved 5 n que TO Teme ue o ml e wi uz Thelastfeld Dretieved mumFesi fed Dda U2 The last field IDs data retrieved The second field ID retrieved The second field ID s data Doc 7430 3810 Rev 02 Page 70 DMU380ZA Series User s Manual MEMSIC gt 9 DMU380ZA Advanced UART Port BIT 9 1 Built In Test BIT and Status Fields Internal health and status are monitored and communicated in both hardware and software The ultimate indication of a fatal problem is a hardware BIT signal on the user connector which is mirrored in the software BIT field as the masterFail flag This flag 1s thrown as a result of a number of instantly fatal conditions known as a hard failure or a persistent serious problem known as a soft failure Soft errors are those which must be triggered multiple times within a specified time window to be considered fatal Soft errors are managed using a digital high pass error counter with a trigger threshold The masterStatus flag is a configurable indication as determined by the user This flag is asserted as a result of any asserted alert signals which the user has enabled The hierarchy of BIT and Status fields and signals is depicted here BliTstatus Field masterFail hardwareError e hardwareBIT Field powerError gt hardwarePowerBIT Field inpPower inpCurrent inpVoltage fiveVolt threeVolt two
138. te address of the desired register e g 0x35 for self test e Change the most significant bit of the address to 1 the write bit e g 0x35 becomes OxB5 e Create the write command by appending the write bit address combination with the value to be written to the register e g OXB504 see Table 25 for a description of the self test register Figure 12 illustrates the sensor self test command sent over SPI Figure 12 Single Register Write to Initiate Self Test As described in Section 5 7 1 the self test command bit remains set until the test completes The master must read from register 0x34 to assess if the test 1s complete Figure 13 Note as described in the Register Reads section a register read returns two bytes in this case a read from register 0x34 returns data from registers 0x34 self test information and 0x35 data ready settings The value read from the DMU380ZA must be parsed according to Table 25 to determine self test completion status nSS CLK MOSI 0x3400 0x0000 gt Figure 13 Polled Read of the Self Test Data Ready Register Doc 7430 3810 Rev 02 Page 39 DMU380ZA Series User s Manual MEMSIS gt 5 7 Configuration Registers 5 7 1 Self Test Data Ready Self test and data ready registers are combined into a single 16 bit register at memory location 0x34 individual bits are assigned according to Table 25 Table 25 Self Test Data Ready Register Base Address 0x34 Read Write Bits Description
139. the calibrationRequest field will be 0x000B or 0x000C CD Payload Contents Byte Offset calibrationRequest op opo The requested calibration task 20046 G The x hard iron bias softlronScaleRatio U2 2 2 16 The scaling ratio between the x and y axis softlronAngle l2 2 pi 2 16 Rad The soft iron phase angle 360 2M6 Deg between x and y axis Doc 7430 3810 Rev 02 Page 53 DMU380ZA Series User s Manual MEMSIC gt 7 2 9 Error Response Error Response ASCII NAK NAK 0x1515 Packet Type Length Payload 0x5555 0x1515 NAK payload lt CRC U2 gt The unit will send this packet in place of a normal response to a failledInputPacket Type request if it could not be completed successfully NAK Payload Contents Byte Offset O 4 failedinputPacketType Hx Je Pe the failed request 7 3 Output Packets Polled The following packet formats are special informational packets which can be requested using the GP command 7 3 1 Identification Data Packet Identification Data ID 0x4944 Packet Type Length Payload 0x5555 0x4944 lt ID payload gt lt CRC U2 gt This packet contains the unit serialNumber and modelString The model string is terminated with 0x00 The model string contains the programmed versionString 8 bit Ascii values followed by the firmware part number string delimited by a whitespace ID Payload Contents o swaNume Ui Untsremume 4 mese SN Uh
140. the DMU380ZA Series product by itself you will not be correcting for the magnetism in the user system If you then install the DMU380ZA Series product in the system i e a vehicle and the vehicle is magnetic you will still see errors arising from the magnetism of the vehicle Mag Alignment Procedure Using NAV VIEW The Mag Alignment Procedure using NAV VIEW can be performed using the following steps below 1 Select Mag Alignment from the Configuration drop down menu at the top 2 If you can complete your 360 degree turn within 120 seconds select the Auto Terminate box 3 Select the Start button to begin the MagAlign Procedure and follow the instructions at the bottom of the screen as shown in Figure 27 below Doc 7430 3810 Rev 02 Page 89 DMU380ZA Series User s Manual MEMSIC X Hard Iron Offset Y Hard Iron Offset Soft Iron Ratio Soft Iron Angle Instructions Slowly rotate the unit on a level surface about the Z axis until HAV VIEW reports that the calibration is done The operation will timeout in 120 seconds If you want to stop make sure switch is OFF before clicking STOP External Mag Leveling Alignment Rotational Alignment EE Essa Roll Offset Pitch Offset Cancel 439 1 Roll 0 4 Pitch 0 1 Yaw Magnetometer Dutput Y Field Gauss X Field Gauss Figure 27 Mag Alignment 4 Rotate the AHRS or INS380ZA product through 380 degrees of rotation or until you recei
141. tionality that the VG380ZA replicates by providing dynamic roll and pitch measurements in addition to the IMU data The dynamic roll and pitch measurements are stabilized by the using the accelerometers as a long term gravity reference Unlike the VG400 and earlier MEMSIC VG Series products the VG380ZA can also output a free integrating yaw angle measurement that 1s not stabilized by a magnetometer or compass heading see AHRS380ZA or INS380ZA for stabilized heading At a fixed 200Hz rate the VG380ZA continuously maintains both the digital IMU data as well as the dynamic roll and pitch data As shown in the software block diagram Figure 4 after the Sensor Calibration block the IMU data is passed into an Integration to Orientation block Please refer to the Figure 5 if external GPS aiding will be used The Integration to Orientation block integrates body frame sensed angular rate to orientation at a fixed 200 times per second within all of the DMU380ZA Series products For improved accuracy and to avoid singularities when dealing with the cosine rotation matrix a quaternion formulation is used in the algorithm to provide attitude propagation As also shown in the software block diagram the Integration to Orientation block receives drift corrections from the Extended Kalman Filter or Drift Correction Module In general rate sensors and accelerometers suffer from bias drift misalignment errors acceleration errors g sensitivity nonlinearity squ
142. to a large ferrous object When the Use Mags switch is turned from OFF to ON the INS380ZA will reinitialize the yaw heading angle with the compass reading provided from the magnetic field sensor readings Restart On Over This setting forces an algorithm reset when a sensor over range occurs i e a rotational Range rate on any of the three axes exceeds the maximum range The default setting is OFF for the INS380ZA Algorithm reset returns the INS380ZA to a high gain state where the INS380ZA rapidly estimates the gyro bias and uses the accelerometer feedback heavily This setting is recommended when the source of over range is likely to be sustained and potentially much greater than the rate sensor operating limit Large and sustained angular rate over ranges result in unrecoverable errors in roll and pitch outputs An unrecoverable error is one where the EKF can not stabilize the resulting roll and pitch reading If the over ranges are expected to be of short duration 1 sec and a modest percentage over the maximum operating range it is recommended that the restart on over range setting be turned off Handling of an inertial rate sensor over range is controlled using the restartOnOverRange switch If this switch is off the system will flag the overRange status flag and continue to operate through it If this switch is on the system will flag a masterFail error during an over range condition and continue to operate with this flag until a quasi stat
143. to stabilize heading heading will run open loop or be stabilized by GPS track 1 Use mags to stabilize heading Use GPS 2 0 Do not use GPS to stabilize the system 1 Use GPS when available Aid 0 Do not lock yaw when GPS speed is near zero 0 75 m s 1 Lock yaw when GPS speed is near zero a restart the system after a sensor over range ee n O vehicle is static force high gain corrections 1 vehicle is dynamic use nominal corrections 8 6 Hard and Soft Iron Values These fields allow access to hard iron bias and soft iron scale ratio values for magnetometer alignment See Table 39 Table 39 DMU380 Magnetic Alignment Parameters X Hard ron Bias 0008 TT Y Hard lon Bias 000A 22 6 Soft Iron Scale Ratio 0x000B 226 fe The hard iron bias values are scaled from 1 1 Gauss These values are subtracted from the tangent plane magnetometer vector before heading is calculated The soft iron scale ratio is scaled from 0 2 and is multiplied by the tangent plane x magnetometer value before heading is calculated 8 7 Heading Track Offset This field is used to set the offset between vehicle heading and vehicle track to be used by the navigation mode filter when no magnetometer heading measurements are available See Table 40 Table 40 DMU380 Heading Track Offset FieldName Name LT ID Format Scaling Unit Heading Track Lo ANN pne a Radians heading track 0x000C 360 2 16 Doc 7430 3810 Rev
144. ual MEMSIS gt Accelerometers scaled to a range of 10 10 g Magnetometers scaled to a range of 1 1 Gauss Temperature scaled to a range of 100 100 C S0 Payload Contents o xw Io 20246 g Xaccelerometer 2 jywe 02 202M6 g Yaceermeer A Accel 0D 20246 g Zaccelerometer xRate 2 T pi 2 16 rad s X angular rate 1260 2M16 sec yRate 12 7 pi 2 16 rad s Y angular rate 10 1260 2 16 sec 28 Bistatus U2 Master BIT and Status 7 4 2 Scaled Sensor Data Packet 1 Default IMU Data Scaled Sensor Data S1 0x5331 Packet Type Length Payload 0x5555 0x5331 S1 payload lt CRC U2 gt This packet contains scaled sensor data Data involving angular measurements include the factor pi in the scaling and can be interpreted in either radians or degrees Angular rates scaled to range of 3 5 pi pi or 630 deg sec to 630 deg sec Accelerometers scaled to a range of 10 10 g Temperature scaled to a range of 100 100 C 1 Payload Contents Name DAxd ooo sg Xaxeeomde o ame g Y accelerometer 4 ze Ji uno s Zaceeomer T pi 2 16 rad s X angular rate 1260 2116 sec 2 2 T pi 2M6 rad s Y angular rate 12607 2 16 sec 10 zRate 12 7 pi 2416 rad s Z angular rate 1260 2 16 sec Doc 7430 3810 Rev 02 Page 56 DMU380ZA Series User s Manual MEMSIC gt xRateTem
145. urrent release of the software does not have this functionality Future releases of software will restore this functionality The magnetometer ranges is 4 gauss thus 2 5 gauss 1s the recommended maximum hardiron that should be tolerated for the installation and still provide ample resolution and headroom to properly determine the earth s magnetic field strength 0 5 gauss If the hard iron estimates are larger than 2 5 gauss then a different installation location should be investigated Read Unit Configuration NAV VIEW allows users to view the current settings and calibration data for a given DMU380ZA Series unit by accessing the Read Configuration selection from the Configuration drop down menu See Figure 29 From this dialog users can print a copy of the unit s current configuration and calibration values with the click of a button Simply select the Read button at the top of the dialog box and upon completion select the Print or Print Preview buttons to print a copy to your local network printer This information can be helpful when storing hard copies of unit configuration replicating the original data sheet and for troubleshooting if you need to contact MEMSIC s Support Staff Dock 7430 3810 Rev 02 Page 91 DMU380ZA Series User s Manual MEMSIC aaa Read Unit Configuration e eme Unit ID Model Version Serial Number M Unit Default Settings Packet Type Packet Rate
146. utOfBounds error flag available in the TO packet The current release of this software does not currently implement this feature however In future releases this functionality will be restored The user can access the hardIron and softIronScaleRatio calibration data as configuration fields in NAV VIEW or by using the communication protocol over UART or SPI Also the softwareError bit of the masterFail byte within the BIT word is transmitted in every measurement packet When the AHRS380ZA has not been properly calibrated this softwareError bit will be set to fail high The current release of this software does not currently implement this feature however In future releases this functionality will be restored In order for the AHRS380ZA calibration to work properly the AHRS380ZA must be installed in your system prior to calibration If you perform the calibration process with the AHRS380ZA by itself you will only correct for the magnetism in the AHRS380ZA itself If you then install the AHRS380ZA in a vehicle for instance and the vehicle is magnetic you will still see errors arising from the magnetism of the vehicle The AHRS380ZA must be calibrated after installation and prior to use of the system The AHRS380ZA also provides a command interface for initiating the hard iron soft iron calibration without the using NAV VIEW The user can send a WC command to initiate the calibration and then rotate the user system through 360 degr
147. ve a message to stop 5 Once you have completed your rotation you will be given data concerning the calibration accuracy The X and Y offset values indicate how far the magnetic field has been offset due to hard iron affects from components surrounding the unit In addition you will see a soft iron ratio indicating the effect of soft iron on the AHRS of INS380ZA product 6 Save this data to the AHRS or INS380ZA product by selecting the Apply button See Figure 28 Doc 7430 3810 Rev 02 Page 90 DMU380ZA Series User s Manual MEMSIC gt Magnetometer Alignment New Settings x Hard Iron Offset Y Hard Iron Offset Soft Iron Ratio 0 035380 D 0184 0 99997 ms Figure 28 Magnetometer Alignment 7 Upon completion of the Mag Alignment Procedure the heading accuracy should be verified with all third party systems active using a known reference such as a compass rose GPS track or a calibrated compass Heading inaccuracies greater than the values specified on the data sheet or fluctuating heading performance may be an indication of magnetic field disturbances near the unit gt IMPORTANT An acceptable calibration will provide X and Y Hard Iron Offset Values of lt 2 5 and a Soft Iron Ratio gt 0 95 If this procedure generates any values larger than stated above the system will assert the softwareError dataError magAlignOutOfBounds error flag See section 9 for details on error flag handling Note that the c
148. vibration Doc 7430 3810 Rev 02 Page 28 DMU380ZA Series User s Manual MEMSIC FreelyIntegrate should only be set to ON for severe launch conditions Normal takeoff dynamics that a standard aircraft would experience will see the best performance with this setting in the OFF position 4 3 Rotorcraft Rotorcraft is a category of heavier than air flying machines that use lift generated by rotors They may also include the use of static lifting surfaces but the primary distinguishing feature being lift provided by rotating lift structures Rotorcraft includes helicopters autogyros gyrodynes and tiltrotors The rotor blade dynamics itself is much faster than that of the fixed wing aircraft and contains high frequency components At the same time however it may cause severe vibrations on the airframe Also the overall dynamics translational and rotational motion of the rotor craft is much slower than the fixed wing aircraft due to a mechanical mechanism of rotors generating the aerodynamic forces and moments Table 15 provides the recommended advanced settings for two different dynamic conditions Table 15 Recommended Advanced Settings for Rotorcraft Recommended Product AHRS380ZA or INS380ZA Dynamic Condition Recommended Settings High Dynamics Normal Dynamics with uncoordinated tail motion 5 Hz 5 Hz 5 Hz 5 Hz UseMags Z Filter Accel The helicopter can change its heading angle rapidly unlike the airc
149. w and or Compass View from the View drop down menu at the top of the page See Figure 22 PE Compass View HDG 30 0 Figure 22 Horizon and Compass View Doc 7430 3810 Rev 02 Page 84 DMU380ZA Series User s Manual MEMSIC gt Packet Statistics View Packet statistics can be obtained from the View menu by selecting the Packet Statistics option See Figure 23 This view simply provides the user with a short list of vital statistics including Packet Rate CRC Failures and overall Elapsed Time that are calculated over a one second window This tool should be used to gather information regarding the overall health of the user configuration Incorrectly configured communication settings can result in a large number of CRC Failures and poor data transfer Packet Statistics Packets Received 146442 CRC Failures Ave Packet Rate Hz 102 30 Elapsed Time 00 24 23 Reset Done Figure 23 Packet Statistics Unit Configuration The Unit Configuration window See Figure 24 gives the user the ability to view and alter the system settings This window 1s accessed through the Unit Configuration menu item under the configuration menu Under the General tab users have the ability to verify the current configuration by selecting the Get All Values button This button simply provides users with the currently set configuration of the unit and displays the values in the left column of boxe

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