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1. uonoejes 1e ie2e 33 CL eseo buipjing er uonejueuie duit MS Z ubisap vod UE ubisep pueogeseg z HW3 fep 100p uedo 7 y M suures add Sul pesq ubisap jeuueu e 1deouoo aJempJeH v A DLR and SSC cooperation Schedule EurRoOLAUNCH Page 20 3 2 zs LS 0S 6v 8v P Jequie2eg JequiSAON by Ov GE BE LE 9 z zz bz OZ Kew 6L 8L L 9L SL PL 1deouoo oiuonoe a CS jdeouoo asemyos Ud uonelu s uq 1 8 swexg Md uojesedaig 1g 34 uoieosey zz 439M yow BX18 ARCA SED v5 0 12JAN15 docx Figure 2 Schedule Page 21 EuroLAUNCH Student Experiment Documentation 3 3 Resources 3 3 1 Manpower Stefan Biereigel spends about 15 hours per week to work on the experiment In peak times much more From 30 06 2014 to 19 07 2014 he is writing exams so the available time is lower Severin Haas spends about 15 hours per week to work on the experiment In peak times much more From 30 06 2014 to 19 07 2014 he is writing exams so the available time is lower From mid November 2014 to end of January 2015 he is going to write his bachelor thesis In this time he has to reduce the work to a lower level Sebastian Udich will spend about 5 hours per week to work on the experiment Johannes Willenb cher can spend 7 5 hours per week to work on the experiment In peak tim
2. Test completed Successfully done The temperature trend can be seen in Chapter 4 6 As expected from the thermal simulation no problems were found The highest measured temperatures were about 40 C which is 20K difference to room temperature BX18 ARCA SED v5 0 12JAN15 docx Page 62 JS E UROLAUNCH A DLR and SSC cooperai Student Experiment Documentation Test Setup for Vacuum Tests All components are equipped with temperature sensors m K Ae TZ al Picture 11 Vacuum Test Setup Table 5 4 5 Power test Test number 5 Test type Power test Test facility EAH Jena Tested item Whole experiment Procedure The whole experiment was switched on and the power and duration consumption was measured Measured current 100mA at a voltage of 10V P 100mA 10V 1W Test campaign 10min duration BX18 ARCA SED v5 0 12JAN15 docx Page 63 Student Experiment Documentation EupoLAUNCH Test date 27 08 2014 Test completed Done The test result shows that the experiment fulfils the requirements Table 5 3 6 EMC test Test number 3 Test type EMC test Test facility EAH Jena Tested item Whole experiment Procedure Acceptance test 30min and duration The experiment was put into a GTEM chamber and powered up Then the electro magnetic levels of the experiment were measured in every direction Test campai
3. BX18 ARCA SED v5 0 12JAN15 docx Page 34 EupoLAUNCH Student Experiment Documentation 9000004 006 000000953 d Ad dog Picture 6 The built ARCA baseboard top and some connectors The electronics schematic and layout is finished any remaining problems were discussed and solved after CDR All PCBs are assembled and ready for further testing The first receiving tests were very good and the receiving quality excellent The team could receive air planes from a distance up to 380km These tests were done with a smaller antenna than that which will be used during the experiment Grounding strategy The experiment box will not be connected to battery ground Battery ground will only be used on both the PCBs on ground planes Mounting spacers will not have low impedance electrical contact to the PCB ground planes Ethernet is an electrical insulated interface meaning there is no ground connection needed to the Ethernet Switch Ethernet Shield will not be connected to GND in our experiment and should therefore be connected in the Ethernet Switch The coaxial antenna cable outer conductor will not make any contact to the case to not cause a ground loop Potential problems and solutions At CDR there were concerns about the following aspects of the receiver e HF sensitivity is too low e RF rejection of out of band transmitters for example GSM is not high enough therefore decreasing input sensitivity
4. EurROLAUNCH A DLR and SSC cooperation SED Student Experiment Documentation Document ID BX18 ARCA SED v5 0 12JAN15 Mission BEXUS 18 Team Name ARCA Experiment Title Advanced Receiver Concepts for ADS B Team Name University Student Team Leader Haas Severin EAH Jena Team Members Biereigel Stefan EAH Jena Udich Sebastian EAH Jena Willenb cher Johannes HS Mannheim Z llner Hannes EAH Jena Version Issue Date Document Type Valid from 5 0 12 January 2015 EAR 12 Jan 15 Issued by ARCA Team Approved by BX18 ARCA SED v5 0 12JAN15 docx CHANGE RECORD 2013 12 11 2014 02 14 2014 02 24 2014 04 20 2014 06 21 2014 07 07 2014 07 09 2014 08 31 2015 01 12 Abstract New Version All 1 3 2 1 2 2 2 3 2 4 9 1 4 5 1 2 1 3 1 4 1 5 1 2 1 2 2 2 3 2 4 3 1 3 2 3 3 2 3 3 3 3 4 3 5 4 2 1 4 2 2 4 2 3 4 2 4 4 4 4 5 4 6 4 7 4 8 5 1 52 5 3 6 1 2 6 1 4 6 3 7 2 7 3 8 1 8 2 Appendix B Appendix C References 1 1 1 3 1 4 1 5 2 21 332 34 4 2 1 4 2 2 4 2 3 4 3 4 5 4 6 4 7 4 8 4 9 5 2 5 3 6 1 1 6 1 2 6 2 6 4 6 5 7 1 Preface 2 3 3 1 3 2 3 3 2 3 4 5 2 6 1 1 3 1 3 3 2 6 1 3 6 1 4 6 1 5 6 3 3 2 3 4 4 2 2 4 4 4 5 5 1 5 2 5 3 6 1 1 6 1 5 6 2 6 3 1 5 1 3 2 3 4 5 1 5 2 5 3 7 3 7 4 7 5 Blank Book 2013 PDR EAR Pre Campaign Final report BX18 ARCA SED v5 0 12JAN15 docx
5. Keywords BEXUS SED Student Experiment Documentation ARCA Aircraft ADS B BX18 ARCA SED v5 0 12JAN15 docx CONTENTS CHANGE RECORD EE 2 CONTENTS Em 5 PREFACE s MH T E 9 ER EE 10 1 INTRODUCTION ee east 11 1 1 Scientific Technical Background 11 1 2 Mission Statement Head 11 1 3 Experiment Objectives tois bac alode o areas 11 1 4 Experiment Concept 12 1 5 Team Eeler aaa a aaa ses 12 1 9 17 Gontaebt Polls 12 152 Team Members uu usu uuu maa LR ML DAT bes 12 2 EXPERIMENT REQUIREMENTS AND CONSTRAINTS 15 2 1 Functional Requirements Aen 15 2 2 Performance reouirements ee 15 2 3 Design Heourements AEN 15 2 4 Operational Requirements ssssssneseeeseeeeenertrrreseretrtrnnnrrneserrrnrnnnnneneee 16 25r EE 16 3 PROJECT PLANNING ers 17 3 1 Work Breakdown Structure WD 17 3 2 Sede nre AA 20 3 3 ROS OCS AA 21 esca Mes iie EEN 21 33 2 NE nee re 21 3 33 External SUpPOfl iui us u u uuu ped I An ERU d aS Had 22 94 Outreach Approach asc apogr 22 2 5 HISKFIGUISIGE aa edi AA KANA KAN C Sua UD GU pd sedens 23 4 EXPERIMENT DEGSCHRIDTION 26 4 1 Experiment Setup ooi cedet p xdi reste AA 26 4 2 Experiment Interfaces EEN 26 D SM NEM len sci M a ee er Geen Dm 26 4 2 2 Elected EE 27 4 2 3 Radio Freouencies AEN 27 4 224 Thermal 28 4 3
6. Page 72 EupoLAUNCH Student Experiment Documentation Thermal Some components get too hot or cold 196 to work perfectly but do still work Simulation results are off All components are in the right 5 temperature profile and are working correct Simulation results are according to real behavior Power System Power system fails to work stable 096 All components receive their necessary 596 power to work correct BX18 ARCA SED v5 0 12JAN15 docx Page 73 E UROLAUNCH Student Experiment Documentation 7 DATA ANALYSIS AND RESULTS 7 1 Data Analysis Plan Because the goal of the experiment is to evaluate which advantages an aircraft based ADS B monitoring system could have the received data will be analysed under the following criteria e What is the average range of received planes e What is the maximum range of received planes e Number of packets per second minute o Is there a need for other better performing reception concepts e Are single planes traceable without interruption But as stated in the experiment objectives not only the receiver performance matters for the success of our experiment As a whole system was developed without relying on off the shelf parts the following criteria are also to be analysed e Did all parts of the electronics work as they should Why and where did errors occur e How well does the thermal simulation match the measured temperatur
7. 14 Recorded airplane tracks during the flight visualised with planeplotter 7 4 2 Hardware design The plain case structure turned out to be pretty robust and reliable We used vibration reducing dampers for the attachment of the experiment to the gondola to protect the PCBs at the gondola landing Afterwards there were no shock related damages visible on the experiment Picture 15 Experiment mounted in the gondola onto shock dampers Also the application of thread lock adhesive and lock washers has proven itself After the flight and landing there were no loose screws and even the threads of the screws for the lid fixation in the aluminium I sections which BX18 ARCA SED v5 0 12JAN15 docx Page 77 EuroLAUNCH Student Experiment Documentation Seo s have been tightened and loosened several times during assembly and testing were in a good shape 7 4 8 Electronics design All over the electronics development was very successful During the fabrication only some minor directly fixable bugs were detected In detail they were e An unpopulated power connection resistor for the supply of the ethernet PHY chip e A swapped population of a series and a pullup resistor So the PHY was not configurable at all because a config interface line was stuck at VCC e A missing power connection at one FPGA power pin due to a text in the schematics at the position where the connection should have been This resulted in a non
8. 50mA 250mW ADC 3 3V 25MA 80mW Sum 920 mW BX18 ARCA SED v5 0 12JAN15 docx Page 43 EurRoLAUNCH Student Experiment Documentation As reception and decoding are running the entire mission peak and average power are the same for every part of the electronics Note As we were not able to measure the currents for every supply voltage on the FPGA and ARM boards the current and power is based on the supply voltage for the entire board 5V for the FPGA development board and the ARM board Appropriate maximum ratings for the load bearing capacity of the voltage regulators are taken into consideration by sticking to the design of development boards and reference implementations in datasheets and by using datasheet values for maximum currents on every voltage rail Power supply concept The experiment will get a 28V power supply from the BEXUS gondola This voltage will be distributed to different voltages which will be needed by the experiment The first switching regulator will convert a big range of input voltages to 5V These are used as an intermediate voltage On the ARM board 1 0V 1 8V and 3 3V are needed 3 3V and 1 0V can be used as the I O and core voltages of the FPGA as well as the 3 3V supply the Ethernet PHY the ADC and the RF receiver The FPGA needs one more voltage for the analogue PLLs which is 2 5V It is generated by a LDO regulator directly on the base board MAAN 5V 2A e 25 ARM board
9. Experiment eu enn Santee eens 29 4 4 Mechanical Design 29 4 5 Electronics Design EE 31 BX18 ARCA SED v5 0 12JAN15 docx 4 6 Thermal Designs AA 37 4 7 Power System cent esas teg cube tasso p cadi teda en cea 42 4 8 Software Design uu u u AALALA pan 44 4 9 1 EPOAJDSSIBU ir eere ore OPERE LUCERE DERE VERRE 45 48 2 ARM Software designs ordei Datus ux ie PL ELLA 46 4 9 Ground Support Equipment 48 EXPERIMENT VERIFICATION AND TESTING 50 5 1 Verification MAs een 50 oe a N a E AN EA E E O UA ERLE OR CTA EOD 52 5 3 ost EE 57 LAUNCH CAMPAIGN PREDARATION esses 68 6 1 Input for the Campaign Flight Requirement Plans 68 6 1 1 Dimensions and Mass ee 68 61 2 EE 68 6 1 3 Electrical Interfaces 69 6 1 4 Launch Site Requirements 69 6 1 5 Experiment Shipping maam BAGA AA 70 6 2 Preparation and Test Activities at Esrange 70 6 3 Timeline for Countdown and Flight 70 6 4 Post Plight Activities aaa ANAN Aamin 71 6 5 System SUCCESS reg 71 DATA ANALYSISANB RESULTS zB ege 73 721 Data Analysis Plans 73 Te e ER EE 73 7 3 Launch Campaign MER 73 oda RESUS Re M Neh T 5 7 4 1 Experiment resu
10. Experiment placed into the gondola BX18 ARCA SED v5 0 12JAN15 docx Page 75 Student Experiment Documentation EupSLAUNCH 7 4 Results 744 Experiment results During flight we faced several unexpected conditions First at an altitude of 7km we noticed first drop outs of received packets It seemed that there were periods 30 seconds long where not a single packet was received This was unusual because in these altitudes many planes should have been visible and always seemed to cause a continuous stream of packets As the balloon ascended further these dropouts seemed to get more frequent and longer Eventually the data rate in peaks dropped from 550 packets per second to about 2 5 packets per second Dropouts seemed not to be periodic and occurring before the receiver After arriving back at home a receiver test indicated that the receiver is still intact and was not the cause of the problem The data rate over time is indicated in the following diagram 70 000 4 60 000 50 000 8 Received packets w 20 000 r 45 r 35 30 25 Mi Packets Valid 20 Flights Unique r 35 10 50 100 150 200 250 300 350 400 Time min Nevertheless we were able to track airplane routes continuously as seen in the following picture BX18 ARCA SED v5 0 12JAN15 docx Page 76 EurOLAUNCH Student Experiment Documentation Picture
11. Mode S beast One receiver costs around 400 See Risk Register for further information 3 3 3 External Support During the whole process we are consulted by Prof Burkart Voss from our faculty He is also the leader of the master course space electronic Additionally we will get technical support from the institute of integrated circuits of Prof J rgen Kampe There we can use the available climatic cabinet for testing To test the electromagnetic compatibility of the experiment we can use the GTEM cell from Prof Ludwig Niebel in our university Vacuum tests can be done at the physics department of Friedrich Schiller University Jena and with desiccators available at EAH Jena 3 4 Outreach Approach To inform the public about our project and the results we have done the following things Website We created a website http bexus arca de where we describe our experiment and the concept in detail Additionally there will be updates about reached milestones and general project status updates Currently the website is still in progress so there is not much content We will update it in the next weeks Twitter During the whole project we are tweeting news and information at the short message service Twitter The account name is BEXUS ARCA http twitter com BEXUS ARCA Podcasts In January 2014 we talked to Markus V lter responsible for podcast OmegaTau http omegataupodcast net Together we planned a BX18
12. S Mea cv Wew SIUM ZE sid ouoo eunjonus MS 1epooeg aa G SEI Lt SuM LE EU MH v MS uoipn uenseqos 195104918 vele WA Seuueuor lJu uiui dx3 YIHV A ddns smod ping 12 Jepooeg pjing O pu luo1j ping s A ddns semod uBisag p Z Jepooeg ubisag ez pu luo1j ubisag 2 2 guu luy pina L OIuo1 o89 3 Z jeujjoz s uupH uoneo IUNWWOD EL Bujuueld Z L lq uu 3 UL jueuu amp eueui 199l01d SELH uua og Figure 1 Work Breakdown Structure BX18 ARCA SED v5 0 12JAN15 docx Page 18 EupoLAUNCH Student Experiment Documentation WP Task Responsible Person Supporter 1 1 Create timetable Severin Haas 1 2 Planning Severin Haas Stefan Biereigel 1 3 Communication Severin Haas 2 1 Build antenna Hannes Z llner Stefan Biereigel Severin Haas 2 2 Design frontend Severin Haas Stefan Biereigel 2 3 Design decoder Hannes Z llner Stefan Biereigel 2 4 Design power supply Hannes Z llner 2 5 Build frontend Hannes Z llner Stefan Biereigel Severin Haas 2 6 Build decoder Hannes Z llner Stefan Biereigel Severin Haas 2 7 Build power supply Hannes Z llner Stefan Biereigel Severin Haas 3 1 Write decoder software Stefan Biereigel Severin Haas 3 2 Write main computer Stefan Biereigel Severin Haas software Hannes Z llner 3 3 Write ground station Severin Haas software 4 1 Cre
13. T Verbose E Log Seve Picture 5 Temperature profile of simulated vacuum test Maximum temperatures of 39 C were measured in the test near the stationary temperature after nearly 2 hours the simulation shows similar results From these results the final simulation for the BEXUS flight profile can be derived The density of air at 35km height was found to be 0 029 cm3 based BX18 ARCA SED v5 0 12JAN15 docx Page 41 Student Experiment Documentation EuroLauncn on which Icepak can calculate the remaining convection Temperature was assumed to be 60 C u atian IM 46 8407 a 45 6762 e 46 7835 52 4223 C 60 0000 TA Mea 2107 Temperature Point monitors for IcepakProj00 EUR Object face At 0 0172 0 0228 0 00733 Temperature Global min f At 0 00229 0 00411 0 00733 Tempest EL C At 0 00722 0 000947 0 00081 aT tur Seite At 0 00963 0 0212 209109 T Object min At 0 0108 0 00639 0 00206 Ti E Objectmex At 0 0338 0 0282 0 00893 Te ripe rature x pre 20 60 80 Q Done SZ Lowerpri Bi Terminate Print E setrange C Full range F Xg T Xlog F Ylog E Symbols F Lines E Y grid Max loc H F Verbose E Log Seve seve Le Picture 6 Static Simulation Result of 60 C environment near vacuum This simulation assumes the inside air temperature of the box to be 60 C at the start of the simulation As this is not true BE
14. Whole experiment Procedure Acceptance test and duration All experiments were build into the gondola The experiments were powered up and different tests with different E Link signal strengths were made Test campaign 4h duration Test date 08 amp 09 October 2014 Test completed Done Table 5 3 9 Endurance run Test number 9 Test type Endurance run Test facility EAH Jena BX18 ARCA SED v5 0 12JAN15 docx Page 66 EuROLAUNCH A DLR and SSC coop Student Experiment Documentation Tested item Whole experiment Procedure and duration Acceptance test The experiment was build up and the groundstation was set up next to it Everything was powered up and ran for 12h Test campaign 12h duration Test date Mid September 2014 Test completed Done everything works fine Table 5 3 10 Antenna test Test number 10 Test type Antenna test Test facility EAH Jena Tested item Antenna Procedure Acceptance test and duration The experiment was build up and the antenna was placed outside the building We could receive air planes from a distance of 380km so we can say that the antenna works fine Test campaign 12h duration Test date Mid September 2014 Test completed Done Table 5 3 11 Interference test Test number 11 Test type Interference test
15. about half of that power is converted to heat in the IC The other half is dissipated in the magnetics transformers of the LAN Jack An application note by Texas Instruments AN 1540 Page 7 Table 4 confirms this theory By using the corrected power dissipation values and the preliminary power dissipation of the up to date FPGA design simulation results are now very close to the measurements taken in real life conditions Simulation results and comments can be seen below 31 0083 C 433 1729 C 29 1489 C 436 3432 C Temperature Point monitors for IcepakProj00 Done 0 0165 0 0212 0 00733 Temperature 36 3432 C Globel min At C3 84e 005 0 00408 0 00733 Temperature 33 1729 C Bokal 00896 0 0029 0 000812 Temperature 32 6169 C SEOS 20 40 60 80 334 Object min erations p Object max At 0 0377 0 0233 0 00893 Temperature 29 1489 C Mexloc 00172 Done Y Lower pri Bill Terminate Print E Setrange D Fullrange G Save F Xlog F Ylog E Symbols F Lines E Xgrid E Y grid T Verbose W Log Save Picture 4 Static simulation laboratory conditions This picture shows the static simulation result at room temperature 25 C and normal air conditions sea level air pressure Maximum temperature is seen on the Ethernet PHY at 36 C Measurements with an IR thermometer on the prototype yielded 34 5 C so simulation error is at lt 5 All other ICs are in the 31 C 33 C range
16. att ttmmMMTMMee 0e p B 40mA 3 3V 300mA 1 8V 300mA 1 0V 300mA 5V step down step down step down Ar 2 5V 100mA linear reg 9 Figure 5 Power supply concept BX18 ARCA SED v5 0 12JAN15 docx Page 44 EuroLAUNCH A DUR and 880 cooperation Student Experiment Documentation 4 8 Software Design Outline The software running on our payload will be divided in two main parts e Mode S Data decoding done completely in an FPGA e Data processing and up downlink management on an embedded Linux ARM SoC The FPGA was chosen because ADS B Data has a high data rate of 1Mbit s The experiment concept includes oversampling that signal with a factor of 16 with 10 bits of digital resolution Processing that amount of data in real time seems unfeasible in a microcontroller with sufficient power consumption and will therefore be realized inside an FPGA The Digital Signal Processing architecture is outlined in the image below The signal processing flow was first implemented in MATLAB and fed with various test signals sampled by a fast DSO Digital Storage Oscilloscope That way we are able to verify operability and correctness of the algorithm implemented
17. e RF gain is fixed therefore a strong signal can overload and or destroy the receiver input e HF parts are not shielded enough These concerns were all discussed and taken into consideration when finishing the electronics design BX18 ARCA SED v5 0 12JAN15 docx Page 35 EuroLAUNCH Student Experiment Documentation a To calculate RF sensitivity a hand calculation for approximate expected receiving strength was done For a medium size Aircraft Mode S transmission power of 200W was estimated By using the free space path loss as a model for power distribution in air without obstructed sight of the target the following estimation of the link budget can be done e System input sensitivity The output voltage of the AD8313 detector starts to become linear at a level of 70dBm Assuming a minimum link margin of 5dB resulting in 100mV detector output swing 65dBm are needed at the input of the AD8313 Total System gain is calculated as follows G Gant Ginan Gina Gr ti Gritz Gritt3 G 7dB 15dB 15dB 2 3dB 2 3dB 4dB 28 4dB See figure Electronics Concept for details This requires the minimum input signal neglecting noise figures at this point to equal Pag 60dBm 28 4dB 93 4 dBm e Transmission Power Pplane 200W 2 101 ur 53dB plane og Tw m e Free space path loss in dB is calculated by 2 FSPLap 101og u e Maximum free space path loss can be calcula
18. operating Also the connection is flow controlled which includes acknowledgement of packet delivery and retrying in case of delivery failure This is a useful feature for radio links such as the E Link System because packet loss may go unnoticed There are two types of data transmitted via such a connection by the ARCA experiment Type 1 data are status messages These include health information temperature state of the experiment and received ADS B data These are sent once per second if less than N ADS B frames are received If there are more every N received ADS B frames one message is sent to ground support Data Length in Bytes Frame Type Indicator 0x01 1 Temperature data Max 8 depending on number of installed temperature sensors on board Timestamp in standard UNIX time format 4 Length indicator for following payload in Number 2 of Frames N Payload ADS B data packets N 14 Type 2 packets are uplink command acknowledgements These messages include the remotely executed command number and an acknowledgement indicator or the returned error code Data Length in Bytes Frame Type Indicator 0x02 1 Command Number repeated 1 ACK 0x00 NAK error code 1 BX18 ARCA SED v5 0 12JAN15 docx Page 48 EupoLAUNCH Student Experiment Documentation For uplink only one type of data message is used which includes uplink command requests These messa
19. restricted for BEXUS experiments We are aware of the ATC transponder on the E BASS System 4 2 4 Thermal There will be no thermal interfaces The box is shielded as outlined in the thermal design section below in a way that the experiment can stay at a comfortable temperature while on BEXUS flight BX18 ARCA SED v5 0 12JAN15 docx Page 29 Student Experiment Documentation EupoLAUNCH 43 Experiment Components Table 4 1 Experiment summary table Experiment mass in kg 2 Experiment dimensions in m 0 2x0 2x0 1 Experiment footprint area in m 0 04 Experiment volume in m 0 004 Experiment expected COG centre of near the base of the gravity position box in the middle of the footprint area The information in the table lists the dimensions of the E Box For mounting purposes the experiment spans two L profiles between the gondola rails Antenna Dimensions Antenna mass in kg lt 0 5 Antenna length in m 1 Antenna diameter in m lt 0 05 Antenna COG In the middle 4 4 Mechanical Design As the experiment consists mostly of electronic components circuit boards the design will be quite small It will be housed in an aluminium box and will be fastened to the gondola via the provided mounting brackets The drawing in Chapter 4 2 1 shows mechanical dimensions of the experiment box as seen from the outside The experiment box mainly consists of two be
20. test Il Test number 2 Test type Thermal test Test facility EAH Jena Tested item Whole experiment Procedure Acceptance test 1 5h and duration The experiment was put into a temperature chamber and powered up Then the following cooling heating procedures was done e Cooling down from 23 C to 60 C in 30min e Holding a temperature of 60 C for 30min e Warming up again to 23 C in 30min During the whole time the experiment was monitored and used in the same mode as it will be running during the BEXUS flight Test campaign 3h including build up and 1 5h testing duration Test date 15 September 2014 Test completed Done Everything worked fine BX18 ARCA SED v5 0 12JAN15 docx Page 60 EuROLAUNCH A DLR and SSC cooper zz Student Experiment Documentation Temperature Test 2 15 09 2014 60 T Temperature C T T T T T T T T FPGA ADC Ethernet PCB edge Box inside Box outside Hl 60 1 2000 3000 4000 5000 6000 7000 8000 9000 10000 Time seconds Picture 11 Temperature plot during the temperature chamber test Table 5 3 3 super capacitor test Test number 12 Test type Vacuum test Test facility EAH Jena Tested item 3 different aerogel super capacitors Procedure 3 different aerogel super capacitors were placed in a vacuum and duration chamber The air was pumped out and the chamb
21. warming up the PCBs very evenly BX18 ARCA SED v5 0 12JAN15 docx Page 40 EupoLAUNCH Student Experiment Documentation The following boundary conditions were assumed Condition Value Environment Temperature 25 C Air pressure 1013 mbar Emission coefficient el components 0 9 Emission coefficient PCB 0 35 Emission coefficient ESD styrofoam 0 042 Emission coefficient Aluminium surfaces 0 09 Table Boundary conditions for static simulation at room temperature From the vacuum test at FSU Jena see test plan we collected temperature results of the main power dissipating components FPGA Ethernet PHY ARM processor over the course of nearly 2 hours These results can be verified with the Icepak simulation as well 28 L 26 8836 25 0708 36 1205 C 395731C Dann Temperature Point monitors for IcepakProj00 At 0 0164 0 0213 0 00733 Temperature 39 5731 C At 0 00225 0 00322 0 00733 Temperature 36 1205 C At 0 00571 0 000366 0 000812 Temperature 36 1362 C At 0 00998 0 0213 0 00106 Temperature 37 2488 C At 0 00385 0 0183 0 000879 Temperature 37 3541 C At 0 0333 0 0208 0 00893 Temperature 32 3402 C At 0 0148 0 00613 0 00206 Temperature 34 6448 C 40 60 80 Iterations Q Done Y Lowerpri W Terminate Print lsSetrenge C Full range F Xlog F Ylog E Symbols F Lines F Xgrid E Y grid
22. ARCA SED v5 0 12JAN15 docx Page 23 E UROLAUNCH Student Experiment Documentation few podcast episodes about the REXUS BEXUS program ESRANGE and science done with high altitude rockets and balloons including the ARCA experiment For the first mentioned subjects he is planning to talk to scientists and experts from ESA SSC and DLR etc in the end of this year 2014 In addition the following the outreach actions have taken place or will take place e We presented our experiment at the open house event of our university on 12 04 2014 e We gave an interview to the public relations department of EAH Jena which led to the publication of some articles in print media TLZ OTZ papers and online Jenapolis JenaTV e At the training week we got the possibility to present our experiment and the REXUS BEXUS program to a film team The interview and presentation will be aired on ServusTV in TM Wissen a science show broadcasted on a weekly basis e Our university hosts a picture gallery of the student training week featuring our experiment and experiences e On the website of the electronic engineering department of EAH Jena a project page will be hosted making available technical information on the experiment e For the university a poster was designed presenting different experiment aspects as well as the REXUS BEXUS programme in general This poster was shown during the day of research Tag der Forschung at ou
23. Afterwards the algorithm was implemented in VHDL and verified with the MATLAB results ADS B bit clock Manchester Frame Data Decoder KH Builder start of frame reset uw Preamble Detector binary data Threshold Data Filter Slicer Figure 6 Signal processing concept binary data For the on board computer GNU Linux was chosen as the operating system because of its widespread use in embedded computing high reliability and because it is available on the ARM platform Various daemons monitor health status of the experiment temperature inside the box and process the incoming data from the FPGA and handle the up downlink commands issued BX18 ARCA SED v5 0 12JAN15 docx Page 45 E UROLAUNCH Downlink daemon Student Experiment Documentation ADS B data statistics Figure 7 ARM Software concept The ARM SoC also interfaces to a 100Mbit s Ethernet PHY which enables communication with the Up Downlink system Various statistics and raw data will be downlinked to ground support The SoC will also be able to receive uplink commands for manual control of the experiment 4 8 1 FPGA Design The DSP architecture outlined above works as follows Any incoming Signal demodulated by the RF frontend and digitized by the ADC is read into the FPGA The Matched filter in the first stage optimizes signal noise ratio of incoming ADS B signals and improves SNR for interfering signals This is also know
24. Experiment Documentation EuroLAUNCH Page 51 Link downlink D4 2 The experiments shall be designed to use the E Link uplink Done D5 The experiment shall not use more than 0 5 Ah of the gondola battery Done D6 The experiment shall work at the air pressure profile of the BEXUS balloon Done D7 The experiment should be not heavier than 2kg A T Done D8 The experiment size should not be bigger than 0 2m x 0 2m x 0 2m Done D9 The receiver should decode the incoming data at a frequency of 1090MHz for the duration of the BEXUS mission R T Done D11 The antenna shall be designed to receive optimally at a frequency of 1090MHz A T Done D12 The antenna shall have omnidirectional characteristics for optimal receiving performance Done O1 The experiment shall work autonomously without control by the ground station Done O2 The experiment shall be able to enter a secure mode after the balloon is cut off Done 03 Removed O6 The other BEXUS Done 11 BX18 ARCA SED v5 0 12JAN15 docx Page 52 EuROLAUNCH A DLR and SSC coop Student Experiment Documentation experiments shall not emit any EM interference at a frequency of 1090MHz 5 2 Test Plan Table 5 2 Vacuum test Test number 1 Test type Vacuum
25. Test facility Esrange Kiruna Tested item Whole experiment together with the other experiments of BEXUS18 Procedure Acceptance test and duration The experiment was placed into the gondola and every experiment was switched on one after another BX18 ARCA SED v5 0 12JAN15 docx Page 67 Student Experiment Documentation EupoLAUNCH Test campaign 12h duration Test date 08 October 2014 Test completed Done everything works fine Table 5 3 12 Static load test Test number 14 Test type Static load test Test facility EAH Jena Tested item Experiment case Procedure Acceptance test and duration The experiment placed onto the floor and a load of 65kg was placed onto the case Test campaign 5min duration Test date Mid September 2014 Test completed Done everything works fine BX18 ARCA SED v5 0 12JAN15 docx Page 68 EupoLAUNCH Student Experiment Documentation 6 LAUNCH CAMPAIGN PREPARATION 6 1 Input for the Campaign Flight Requirement Plans 6 1 1 Dimensions and Mass Table 6 1 Experiment mass Component Weight Aluminium box 0 95kg Baseboard 0 1kg ARM board 0 05kg Cables 0 1kg Antenna 0 3kg Sum 1 5kg Table 6 2 Experiment mass and volume Experiment mass in kg 1 5kg Experiment dimensions in m 1 box 0 2 x 0 2 x 0 1 1 downward facing ant
26. XUS gondola will happen at 0 C the temperatures in the box will be higher than 43 C But this static simulation tells us that no experiment components overheat because of missing convection nor cool down too low worst case inside air temperature was assumed even in heavy conditions As the model behaviour now fits the prototype and meets our expectations a final transient simulation can be done where a full BEXUS flight profile preparation waiting for launch ascend float descent is modelled As the correctness of the thermal design model is an experiment goal as well various temperature sensors will be placed on the experiment PCBs and on the experiment box wall The logged data can be used for post flight analysis BX18 ARCA SED v5 0 12JAN15 docx Page 42 EurolLaunch Student Experiment Documentation 47 Power System The supplied power to the experiment is internally converted to various other voltages see below The dissipated power is distributed over the two boards as seen in the following images ANSYS R14 5 Academic er Picture 7 Power dissipation on the baseboard 0 00 3000 mm 15 00 ANSYS R14 5 Academic P 0 00 30 00 mm z EE 15 00 Picture 8 Power dissipation on the ARM Computer Board Table 4 7 Power consumption Device U I P ARM board 5V 40mA 200mW Ethernet PHY 3 3V 88mA 290mW HF Front End 3 3V 30mA 100mW FPGA 5V
27. ad System Test Remove before Flight Real Time Clock Student Experiment Documentation Swedish National Space Board Signal to Noise Ratio Start of Data Storage Start of Experiment Student Training Week Software Time before and after launch noted with or To be confirmed To be determined Work Breakdown Structure Zentrums f r angewandte Raumfahrttechnologe und Mikrogravitation BX18 ARCA SED v5 0 12JAN15 docx Page 82 8 2 1 2 3 4 5 6 7 8 9 EupoLAUNCH Student Experiment Documentation References Books Paper Proceedings EuroLaunch BEXUS User Manual 2012 REXUS User Manual 2012 European Cooperation for Space Standardization ECSS Space Project Management Project Planning and Implementation ECSS M ST 10C Rev 1 6 March 2009 SSC Esrange Esrange Safety Manual REA00 E60 23 June 2010 European Cooperation for Space Standardization ECSS Space Engineering Technical Requirements Specification ECSS E ST 10 06C 6 March 2009 European Cooperation for Space Standardization ECSS Space Project Management Risk Management ECSS M ST 80C 31 July 2008 European Cooperation for Space Standardization ECSS Space Engineering Verification ECSS E ST 10 02C 6 March 2009 Project Management Institute Practice Standard for Work Breakdown Structures second Edition Project Management Institute Pennsylvania USA 2006 Empfang und Dekodierung von Flugzeug P
28. ate structure Johannes Team Willenb cher 4 2 Draw CAD Johannes Willenb cher 5 1 Create concept thermo Sebastian Udich simulation 5 2 Design simulation Sebastian Udich 6 1 Temperature test Severin Haas Team 6 2 Vacuum test Severin Haas Team 6 3 Shock test Severin Haas Team 6 4 EMC test Severin Haas Team 6 5 Endurance run Severin Haas Team 7 1 Create homepage Severin Haas Team BX18 ARCA SED v5 0 12JAN15 docx Student Experiment Documentation Page 19 EuroLAUNCH 7 2 Twitter Severin Haas Team 7 3 Planning events Severin Haas Team 7 4 Produce podcast Severin Haas Stefan Biereigel 8 1 Write PDR SED Severin Haas Team 8 2 Write CDR SED Severin Haas Team 8 3 Write IPR SED Severin Haas Team 8 4 Write EAR SED Severin Haas Team 8 5 Write final SED version Severin Haas Team BX18 ARCA SED v5 0 12JAN15 docx SL LO OL eyepdn jee jueuiBeueunoel ouq Jewwey sJempJeH s p snxag Sejep Ay s an un weiBoid uog nno Jaded peusiui4 Jaded Bunun 9 8 s s jeue eyeq eg Sjseopog FZ uredwes yung Buiddiys y uva sjuawiladxa peysiul4 jueuiuedxe Buipiing stwewenoudu 10813 Z 188 oous eg 159 OWA F9 uns eoeiunpua 9 9 Student Experiment Documentation 159 uinnoeA 2 9 jsa eunyesedwei 1 9 Udi MS Ionuoopuno o Ee Naa edAojoJd paysiuly
29. be received BX18 ARCA SED v5 0 12JAN15 docx Page 12 EupoLAUNCH Student Experiment Documentation 1 4 Experiment Concept The payload will consist of an electronic box and an externally mounted antenna The electronics box contains a RF receiver and demodulator an FPGA decoder and an ARM SoC running Linux for data storage analysis and communication to ground support The received and demodulated signals Mode S downlink at 1 Mbit s are processed by an FPGA decoding the data in real time and are then transmitted to the main processor to be logged and transferred to ground support 1 5 Team Details 1 5 4 Contact Point For any questions regarding our experiment please contact the team leader Severin Haas You can reach him via mail severin e sev de or via mobile phone 49 178 8287 494 Address Jenertal 1 07749 Jena Germany For mails concerning the whole team you can also write to arca e sev de 1 5 2 Team Members Severin Haas Project leader Severin studies Electrical Engineering with the main focus on embedded systems at the University of Applied Science in Jena Besides that he is interested in signal processing astronomy and likes to photograph In the ARCA team he is responsible for project management testing outreach work and the ground control software Hannes Z llner Electronics developer Hannes is currently working on his Ph D in the topic of analyzing COTS microcontrollers and memories
30. de the ADS B signal It filters noise and interference from the received signal demodulates the data and transmits the correctly decoded frames to the embedded ARM computer The FPGA and ADC is located on the experiment baseboard Backup Plan If problems arise with the self build Front End and the FPGA decoding unit we are not able to finish in time or results are not good enough there will be the opportunity to buy a finished semi professional Mode S ADS B receiver This receiver will cost around 400 See risk register for more information There will be no huge changes in the software of the ARM computer required as the protocol implemented on the FPGA is compatible to the protocol used in the Mode S Beast and nearly every other Mode S receiver on the market BX18 ARCA SED v5 0 12JAN15 docx Page 32 E UROLAUNCH Student Experiment Documentation ARM embedded computer This ARM computer was developed by Hannes Z llner in his Master Thesis with focus on low power consumption and reliability The schematics for the computer can be found in the online repository as well as the schematics of the receiver and the FPGA base board Picture 4 Picture of existing ARM SoC board including an old base board For keeping time the RTC on the on board computer will be buffered via a gold cap super capacitor This is a small side experiment as we got input from the PDR board to evaluate how well gold caps do
31. discussion at CDR with 200W 53dBm as per datasheet peak power Maximum input power into the receiver is OdBm see TA0232A datasheet Free space path loss at 1090MHz at a 10m distance equals at least 53 2dB As the ARCA receiving antenna has high attenuation in the upward direction towards the ATC transponder further damping of the input signal is expected For further input protection additional countermeasures were taken To be sure the experiment prototype was tested with input levels of gt OdBm and no degradation of performance or defects could be measured Regarding to shielding concerns of the RF demodulator stage components BX18 ARCA SED v5 0 12JAN15 docx Page 37 EuroLAUNCH Student Experiment Documentation On the base board containing the RF demodulator a separate area was reserved for the RF demodulator Also a possibility was provided to solder a shielding cap over the demodulator The RF traces are surrounded by vias and backed by a solid ground plane 4 6 Thermal Design As the experiment payload will mainly consist of circuit boards and wiring the sensitive electronics will have to be kept in the operational limits as specified in datasheets We will use parts that can handle an extended temperature range of at least 40 C to 75 C where possible From previous flights and the ISO Standard Atmosphere Model we can expect temperatures of down to 80 C As the air pressure is very low heat transf
32. duplicating text the relevant aspects of the antenna mechanical design and mounting is written about in 4 2 1 45 Electronics Design The electronics are made up of various blocks distributed on the two experiment PCBs as follows RF receiver on baseboard ADC and FPGA demodulator decoder on baseboard ARM computer on ARM computer board Ethernet PHY for ARM computer on baseboard RF receiver The first design of the RF receiver and demodulator used the well known and often used miniADSB circuit As it proved not to be working well enough under BEXUS operating conditions heavy oscillation leading to reduced input sensitivity we redesigned it to fit our needs It now consists of an input SAW filter tuned to 1090 MHz with low insertion loss 2 3dB an amplifier stage 15dB followed by another filter 2 3dB and yet another amplifier 15dB feeding into the final filter and detector to demodulate the On Off Keying amplitude modulation The achieved goal of splitting the high input gain of the first design 35dB into two amplifiers is that the system does not oscillate anymore because feedback into the sensitive LNAs is reduced The demodulated data is low pass filtered and brought into the digital domain by a 16MS s ADC The RF receiver is located on the experiment baseboard FPGA based demodulator The following FPGA will be an Altera Cyclone IV FPGA that carries out the necessary signal processing to deco
33. e whole experiment Test campaign duration Test campaign date October 2014 Test completed Done see test protocol 5 3 8 BX18_ARCA_SED_v5 0_12JAN15 docx Student Experiment Documentation Page 55 ADLR and SSC EuROLAUNCH Table 5 10 Endurance run test Test number 9 Test type Endurance Run Test facility EAH Jena Tested item The whole experiment Test campaign Many hours duration Test campaign date First half of September 2014 Test completed Done see test result 5 3 9 Table 5 11 Antenna test Test number 10 Test type Antenna test Test facility EAH Jena Tested item The receiving antenna Test campaign duration Test campaign date First week of September 2014 Test completed Done see test result 5 3 10 Table 5 12 Experiment interference test Test number 11 Test type Interference test Test facility Esrange Tested item The whole experiment together with all other experiments of BX18 Test campaign duration Test campaign date 08 October 2014 Test completed Done see test report 5 3 11 BX18 ARCA SED v5 0 12JAN15 docx Page 56 E UROLAUNCH ADLR and SSC Student Experiment Documentation Table 5 13 Super capacitor test Test number 12 Test type Vacuum test Test
34. enna 1 5 x 0 05 x 0 05 Experiment footprint area in m Box 0 04 Antenna 0 0025 Experiment volume in m Box 0 008 Antenna 0 00375 Experiment expected COG centre of Box 0 1 0 1 0 05 gravity position Antenna 0 75 0 025 0 025 6 1 2 Safety Risks The only safety risk that exists in our opinion is a mechanical fault of the antenna causing it to fall off the gondola and injuring people on the ground This case can be surely prevented with a good mounting As the antenna feeding cable is used to hold the antenna itself there will be no additional safety line This was discussed at CDR and confirmed to be OK BX18 ARCA SED v5 0 12JAN15 docx Page 69 Student Experiment Documentation EurolLaunch 6 1 3 Electrical Interfaces Table 6 3 Electrical interfaces applicable to BEXUS BEXUS Electrical Interfaces E Link Interface E Link required Yes Number of E Link interfaces 1 Data rate downlink 20kByte s Data rate uplink 1kByte s Interface type RS 232 Ethernet Ethernet Power system Gondola power required Yes Peak power or current consumption 1W Average power or current consumption 1W Power system Experiment includes batteries No Type of batteries Number of batteries Capacity 1 battery Voltage 1 battery 6 1 4 Launch Site Requirements e Space for 5 people 5 chairs tables e f possible a
35. equency of 1090MHz D10 moved to F4 BX18 ARCA SED v5 0 12JAN15 docx Page 16 EupoLAUNCH Student Experiment Documentation D11 The antenna shall have a gain of at least 7dBi and be optimized for 1090 MHz D12 An antenna shall be mounted outside of the gondola facing downwards while flight D13 The antenna shall receive with omnidirectional characteristics 24 Operational Requirements O1 The experiment shall be able to work autonomously without control by the ground station O2 The experiment shall save all data before the balloon is cut off to prevent data loss in case of short power outages O3 Removed O4 Moved to D12 O5 Moved to D13 O6 The other BEXUS experiment must not emit any EM interference at a frequency of 1090MHz 2 5 Constraints The experiment must comply with the BEXUS schedule and guidelines BX18 ARCA SED v5 0 12JAN15 docx Page 17 EurOLAUNCH Student Experiment Documentation PROJECT PLANNING 3 Work Breakdown Structure WBS 3 1 Z Z UOISJ8 PLOZ 20 40 unu uoisJe JIS eougJnpu3 9 9 yeuly S 8 das uv3 iseopog SUM v 8 eonpojd EA OWS r 9 Gas ddl sjuang ise Su 8 Buiuueld EI yoous 9 das udo MIO MNA WM 2 8 BedawoH Q3S Had el PER Lg 91991 il einjejeduie 9 uone MOM 182 9 uoeaeJno Z Seen uue es u unoo g See uu A9sS See uuenag MS uone s punog aM EE uone nuiis avo MS 1ejnduioo ubisag Z
36. er by air convection is reduced and therefore direct heat transfer to the circuit boards would then be necessary The box encasing our payload will be lined with shielding material minimizing the heat exchange with the cold air outside Thermal simulation results showed that extra heating is not needed as the insulation is good enough and the power dissipation seems to be at a level where electronics neither get too hot or too cold The insulating Styropor will form a box in box in the experiment leaving small room of air for the electronics so no direct contact is made Holes in the styropor will help to guide any wiring to the front panel connectors Electrical power is converted to heat distributed as follows Device P ARM board 200mW Ethernet PHY 145mW Ethernet Jack 145mW RF Front End 100mW FPGA 250mW ADC 80mW Sum 920 mW BX18 ARCA SED v5 0 12JAN15 docx Page 38 EuroLaunch Student Experiment Documentation ANSYS R14 5 Academic 5 0 00 100 00 mm EN 50 00 Picture 3 Thermal insulation concept BX18_ARCA_SED_v5 0_12JAN15 docx Page 39 Student Experiment Documentation EuroLauncn After discussion with the thermal design experts at CDR and reviewing our thermal simulation model thoroughly again we found the error that caused the Ethernet PHY to be overheating Even though power dissipation in the datasheet is said to be 290mW only
37. er was closed for nearly 24h Test date 15 16 04 2014 Test completed Successfully done After air was filled in the chamber all 3 capacitors were ok and resisted the vacuum No mechanical deformation or measurable electrical degradation occurred Table 5 3 4 Vacuum test Il Test number 13 Test type Vacuum test Test facility FSU Jena Tested item All experiment components these include e The FPGA evaluation board BX18 ARCA SED v5 0 12JAN15 docx Student Experiment Documentation Page 61 E UROLAUNCH e The ARM computer e Connected to the Ethernet PHY Procedure and duration The FPGA was permanently loaded with the most recent receiver design and the ADS B generator was used to generate dummy data for the receiver to decode The ARM was running Linux listening to data from the FPGA via UART The Ethernet PHY was connected to the ARM CPU TMP100 Temperature sensors were fixed on all three main components where doubts of thermal properties remained An independent computer was used to read the temperature sensors every minute and record the data for future analysis The vacuum chamber was evacuated very fast much faster than at ascend of the BEXUS gondola to about 1mBar where it was held for nearly 2 hours After that temperatures were expected to be within small margin of stationary levels and air was let in again Test date 18 06 2014
38. es e Did the mechanical design prove robust enough 7 2 Legal issues The reception and publication of ADS B data received from airplanes is not illegal see 8 German article To make sure the experiment is not problematic for legal reasons we will not publicize any raw ADS B data received during the whole flight but only statistical information By doing that we can guarantee that nobody s privacy will be invaded by publishing the SED 7 3 Launch Campaign At the first day everything was unpacked from the shipping box and the last things were assembled After that the experiments were tested Therefore the antenna and the experiment were placed outside of the dome and were connected via Ethernet cable to the ground station After some time we could see 2 airplanes which travelled in the North Western part of Scandinavia Even when there were only 2 airplanes received this was a good sign because the Esrange facility is placed in a valley were the reception conditions are relatively bad After that last power cut off tests and communication tests were done and all were absolved successfully without any incidents BX18 ARCA SED v5 0 12JAN15 docx Page 74 7 EuroLaAuncu ADLR and SSC cooperat Student Experiment Documentation The remaining days at Esrange were quite calm and gave us room to prepare for the upcoming launch Picture 13 Experiment test outside the dome E Picture 13 ARCA
39. es he can spend much more time Hannes Z llner can spend about 7 5 hours per week to work at the experiment In peak times of course much more 3 3 2 Budget Overview over project budget Item Price Parts Main computer 150 PCBs Main Computer 200 Parts Baseboard 120 PCBs baseboard 160 Antenna 40 Aluminium case 100 Cabling Connectors etc 80 bladeRF Board Test and Verification equipment 430 Software license 25 Shipping 120 Total 1425 BX18 ARCA SED v5 0 12JAN15 docx Page 22 EupoLAUNCH Student Experiment Documentation All components listed above will be the costs for 2 experiments which are sponsored by BMWi DLR and administrated by ZARM At the moment the team consists of 5 team members We want to give all team members the possibility to travel to the launch campaign in October 2014 To finance the fifth person we made an application at our university to support us with paying the open flight ticket to Kiruna Our project was funded by the Studentische Forschungs und Entwicklungsprojekte program with 1500 We will use this money to give all team members the possibility to travel to launch campaign and for buying some of the components needed for the experiment If the self built receiver cannot be finished in time or does not work well enough there will always be the possibility to buy a semi professional receiver
40. evel We would like to be notified 15min before the balloon cut off to have the possibility to save and downlink the data 6 4 Post Flight Activities After the experiment is finally back at Esrange the memory flash will be taken off the experiment and the data will be copied This data includes all log files taken by the experiment containing the received ADS B packets This action requires opening the experiment Unscrewing the top removing the Locktite from the SD card and taking it out A Micro SD adapter configured for read only access is used to access the data to prevent accidental data deletion 6 5 System success Table 6 4 System success table Subsystem Description Percentage HF front end Receive data from airplanes in a 30 distance of 300km Receive data from airplanes in 5300km 40 distance FPGA receiver The data stream is received but a few 596 message decoding problems exist The data stream is received and all 3096 messages are decoded correctly ARM computer The data is received but minor 596 problems e g communication restarts necessary etc existed The data is received and all data is 1596 saved correctly Ground support Data is correctly received by the ground station but the commands do not work perfectly Data is correctly received by the ground station and the commands do work perfectly BX18 ARCA SED v5 0 12JAN15 docx
41. experiment tries to evaluate the feasibility of high altitude monitoring of Mode S ADS B transmissions to allow less dense areas to be monitored Future possibilities may include a net of Pico satellites in orbit to monitor the whole earth surface Other possible uses arise for example making flight routes more effective by saving fuel if flight route changes could be made more flexibly The subject doesn t seem to be far fetched as Iridium NEXT satellites will include a system to monitor ADS B transmissions and lridium will provide that data for money to airlines as soon as 2015 1 2 Mission Statement Many aircrafts about 8096 transmit tracking data via Mode S ADS B The status quo is that this data is only observed in regions with dense population The objective of the ARCA experiment is to receive Mode S transmissions in high altitude and evaluate the possible problems and advantages such surveillance would have To do that the electronics including the receiver will be developed built and tested by the team on its own 1 3 Experiment Objectives Primary Objectives e Analysing Mode S esp ADS B data reception possibilities in great height scientific e Developing and building a system which is able to receive ADS B data without relying on pre built hardware technical e Characterisation of the implemented systems and algorithms technical Secondary Objectives Evaluating the maximum radius in which airplanes can
42. facility EAH Jena Tested item Super capacitors also called gold caps different types of foam for thermal insulation Test campaign 24h in near vacuum duration Test date 15 16 04 2014 Test completed Successfully done See test protocol 5 3 3 Table 5 14 Vacuum test Il Test number 13 Test type Vacuum test Test facility FSU Jena Tested item All experiment components FPGA Eval Board ARM Computer Ethernet PCB except RF front end Test campaign 2h in near vacuum 1mBar duration Test date 18 06 2014 Test completed Successfully done See test protocol 5 3 4 Table 5 15 static load test Test number 14 Test type Static load test Test facility EAH Jena Tested item Experiment box Test campaign 2min max 60kg load duration Test date First week of September 2014 Test completed Done see report 5 3 12 BX18 ARCA SED v5 0 12JAN15 docx Student Experiment Documentation 5 3 Table 5 3 1 Thermal test Page 57 E UROLAUNCH Test Results Test number 2 Test type Thermal test Test facility EAH Jena Tested item Component test ARM Board FPGA Base Board RF front end Procedure Acceptance test 1 5h and duration The above mentioned items were put into a temperature chamber and powered up Then the following cooling heating procedures was done e Cooling down from 23 C to 60 C in 30
43. for the usage in space applications His main interest is the development of hardware Therefore he is responsible for the electronics development in the project Stefan Biereigel Software developer Stefan studies Electrical Engineering with focus on embedded Systems at the University of Applied Sciences Jena His personal interest lies in the Radio BX18 ARCA SED v5 0 12JAN15 docx Page 13 Student Experiment Documentation EurolLaunch Communication field with special focus on Software Defined Radio SDR technology He is responsible for Software implementation and the FPGA Receiver Design Johannes Willenb cher Mechanical designer Johannes studies Mechatronics with focus on information technology at the University of Applied Science Mannheim Before university he completed an apprenticeship as a motor mechanic and electrician Having experience with construction and CAD software he is responsible for the mechanical design of the experiment Sebastian Udich Thermal simulation engineer Sebastian Udich finished his engineers degree in Mechatronics and his Master of Science in Space Electronics at Ernst Abbe Hochschule Jena He is now writing his doctorate in cooperation with Technical University Ilmenau about modeling and simulation of ceramic semiconductors He is responsible for thermal management and simulation of the experiment payload BX18 ARCA SED v5 0 12JAN15 docx Page 15 EuroLAUNCH Student E
44. frequency 1090 MHz The received signals will be processed by the demodulator and a signal processor They will be filtered and logged with the help of an embedded computer Some of the received data will be downlinked to ground support where the team can monitor the correct operation of the experiment There will be an uplink command interface available to the team with help of which the experiment can be reset and controlled manually 42 Experiment Interfaces 4 2 4 Mechanical The experiment will be contained in a small aluminium box The antenna to be mounted outside of the gondola will be strapped to the gondola frame The drawing below gives an overview of the mechanical interfaces Picture 1 Experiment Case BX18 ARCA SED v5 0 12JAN15 docx Page 27 EuroLAUNCH Student Experiment Documentation Soc The antenna will not be mounted on a bracket as was planned up to CDR but instead the feeding coaxial cable will be fixed to the horizontal gondola frame bars with the help of cable ties This technique has advantages While the antenna is rigid to maintain its RF properties it can swing freely and will not break off by touching the ground It also reduces security risks as such a flexible construction is unlikely to hurt someone The antenna is kept in place and from falling off the gondola this way This way of mounting the antenna was suggested in the CDR as the bracket may have imposed mechanical difficul
45. ges include the remote command number and an execution parameter Data Length in Bytes Frame Type Indicator 0x03 1 Command Number to be executed 1 Optional parameter 1 49 Ground Support Equipment As ground Support Equipment only a standard consumer grade notebook with an Ethernet port will be necessary as all information from our experiment can be visualized on such a device To have a good tracking of the whole experiment during the flight we will have ground station software where all necessary parameters are displayed Two different kinds of data sets are defined e Health data e payload data ADS B messages The ground station software handles all E Link Ethernet communication with the experiment This software also splits the received data into health data and payload data All necessary information is displayed on a GUI This information includes e Temperature data of all temperature sensors e CPU load Besides that there will be possibility to send commands to the experiment These commands are Get temperature Get CPU Load Reset FPGA Reboot the ARM computer Write out all files which are opened at the moment The ground support software will be programmed in the Python programming language using wxPython for easy visualisation of health data temperatures on the PCBs and in the box and for issuing remote commands The ground support notebook will also run a copy of the PlanePlot
46. gn 2h including build up and measurements duration Test date 18 September 2014 Test completed Done Some spikes are higher than the maximum ratings thin blue line But the thin blue line is basically for consumer electronic devices and therefore a bit more restrictive than the industry regulations BX18 ARCA SED v5 0 12JAN15 docx Page 64 p EuroLauncH A DLR and SSC cooperai Student Experiment Documentation LT ILA LIPE CIN WPP Naa Ei T KU wa HA TT NN Bug n A WO VINO TI Li TL LLL UN CM RUPEE UTILE r i wu PRINT Hz IA E marki poz3o0 sz 0 SEE PROGRAMME MEB EMISSION RESULTS ARCA_B1 MOZ 2 Mz 2231 Def mar 2 pa2600 Bao LE APROGRAMMEWMEBVEMISSIONNRESULTSVARCA Bl AG Picture 12 EMC test results Pe i Picture 12 Experiment placed into the GTEM chamber BX18_ARCA_SED_v5 0_12JAN15 docx Student Experiment Documentation Table 5 3 7 Weight test Page 65 ADLR and SSC EuROLAUNCH Test number 7 Test type Weight test Test facility EAH Jena Tested item Whole experiment Procedure The experiment was put onto the weight and the weight was and duration measured Test campaign 2min duration Test date 15 September 2014 Test completed Done Weight 1 5kg Table 5 3 8 E Link test Test number 8 Test type E Link test Test facility Esrange Kiruna Tested item
47. he timing holds well enough for all data packets so that fixed symbol timing is sufficient The FPGA design source code is publically available at github 9 and open for review by all team members For testing of implementation correctness an ADS B data generator was implemented as well to be able to close the loop and verify the receiver correctness A 1090MHz generator and a RF switch stimulated by the implemented ADS B generator were used to generate input to the RF frontend connected to an ADC breakout board It was possible to decode the sent packets correctly Tests showed that no significant bit errors occur even at low voltage levels therefore assuring us of the working dynamics in the RX design 4 8 2 ARM Software design All software running on the ARM with Linux will be programmed in the C programming language This allows us to access hardware like the serial port in a direct manner As the ARM CPU is running at just 400MHz the increased overhead generated by high level languages is avoided Uplink Downlink modules These software modules manage the communication via E Link over Ethernet to ground support They offer connection to the frame logging module Each of the two modules is listening on one network socket for incoming connections A TCP port is reserved for uplink commands and requests on another port status data and ADS B frames will be sent to ground support They use inter process communication to get sta
48. in space conditions After PDR we tested if different super capacitors can survive in a near vacuum They actually resist the vacuum perfectly We will equip the ARM computer with such a super capacitor for buffering the RTC See Experiment Test and Verification for further information As the experiment will only receive on 1090MHz and not be able to transmit RF we do not expect any interception of mandatory communication systems of the BEXUS gondola or interference with other experiments With this design we can guarantee not to produce unwanted interference locally and for remote receivers BX18 ARCA SED v5 0 12JAN15 docx Page 33 Student Experiment Documentation EurslLauncH gesessen EZ et Q Spa hata ect ces RF receiver BPF IA TN 2 3dB 15dB 2 8dB 15dB AdB CEMETERY Figure 3 The electronics concept For further analysis and tests of the receiver the bladeRF SDR platform will be used to verify receiver functionality and perform measurements It will also be used to stimulate the experiment at the launch campaign and can be helpful in troubleshooting It is possible for us to generate Mode S frames and add artificial noise and other interference for robustness testing As transmission power is very low and all frame check sums are guaranteed to be invalid no real transmissions of aircrafts are intercepted IN Picture 5 The built ARCA baseboard bottom with ARM board top
49. ing fabrication of the device the shielding wires were partially damaged while cutting the isolation off the used coaxial wire Those two points in combination with thousands of shakings during tests using and especially the transport to Esrange let the antenna brake during flight at an altitude of about 7km What has been learned out of that is that a better construction would have been putting the cable segments into one long transparent heat shrinkable tubing without any plastic pipe around So the antenna is completely flexible inspectable and has no moving parts Possibly this trouble might have also been avoided by more team internal reviews So maybe the damaged shielding wires would have been detected Picture 14 Broken antenna after the flight 7 5 2 Electronics The fabrication of new ARM Boards caused trouble We wanted to order from the same company like some years ago where the first revision of the PCBs were produced with the same specification Their response was that the parameters are out of spec and not producible So another company and some layout changes were needed what took several more days for fabrication than planned For next projects it is important to check the design rules of companies again also when there were prior orders with same parameters BX18 ARCA SED v5 0 12JAN15 docx Page 80 E UROLAUNCH Student Experiment Documentation 8 ABBREVIATIONS AND REFERENCES 8 1 Abbrevia
50. lts de eto ea 75 7 4 2 Hardware design EE 76 7 4 3 Electronics design sssssseseeeseessnrrrrrreesetrrrrnnnrnsserrrrnnnnnneeeeet 77 PALA NG OU uicem E D DEP 77 TAS BO AA unu unun uA a teh a days sa 77 7 5 Lessons Learned oo cd e Padi uester edu nandi 78 BOM PRM IN ees 78 1 32 EIgG ORIS uiii uu met na 79 ABBREVIATIONS AND REFERENCES senes 80 8 1 Abbreviations cede edicit qoi ebat LANA 80 8 2 I dzlpie MM 82 Appendix A Experiment Reviews ee 83 Appendix B Outreach and Media Coverage 85 Appendix C Additional Technical Information 86 BX18 ARCA SED v5 0 12JAN15 docx Appendix D Request for Waivers BX18 ARCA SED v5 0 12JAN15 docx Page 9 E UROLAUNCH Student Experiment Documentation PREFACE ARCA Advanced Receiver Concepts for ADS B is a team from the university for applied sciences in Jena which was selected for the BEXUS Balloon Experiments for University Students 18 project The team wants to build a Mode S ADS B receiver which receives messages from aircrafts For the team this project represents the first step into the space business Because of the increasing number of aircrafts in the modern world such a receiver could be mounted on a small satellite to be used as a relay station for Mode S ADS B messages BX18 ARCA SED v5 0 12JAN15 docx Page 10 E
51. min e Holding a temperature of 60 C for 30min e Warming up again to 23 C in 30min During the whole time each component was monitored separately e ARM Board During the test a Linux system was running and monitored via serial connection To see if it s running the program top was executed e HF front end With a spectrum analyser running in tracking mode a signal of 1090MHz was fed into the front end With a voltage meter the amplitude at the front end output was measured e FPGA board During the test the FPGA runs a program which generates ADS B frames and receives them with the current working receiver design Input and output data was monitored with an oscilloscope Test campaign 6h including build up and 1 5h testing duration Test date 15 04 2014 Test completed Done All components worked well at a temperature of 60 for 30min We experienced a short drop out of serial data from the FPGA for about 30 seconds which is OK for testing the FPGA out of its specification down to 40 C BX18 ARCA SED v5 0 12JAN15 docx Page 58 EurOLAUNcH DLR and SSC cooper Student Experiment Documentation Test installation Picture 9 Thermal Test Setup 1 BX18 ARCA SED v5 0 12JAN15 docx Student Experiment Documentation Components placed in temperature chamber Page 59 EuRoLAUNCH A DLR and SSC cooperatio Picture 10 Thermal Test Setup 2 Table 5 3 2 Thermal
52. n as a correlation receiver as the matched filter effectively carries out correlation between the known symbol waveform and the input signal The data slicer recovers digital 1 0 information from the input signal A threshold for the data slicer is generated by a pair of peak detecting discrete RC filter equivalents The filters are working at a higher precision than the input signal In order to not degrade the input signal a margin of about 20dB should be done corresponding to gt 3bit more processing width on internal calculations The digital data is constantly monitored for appearance of preamble patterns If a preamble is present a start of frame signal is issued to the timing clock recovery to the frame decoder and to the Manchester decoder The recovered clock can be used to decode the Manchester encoded bits in the data stream which is then done by the Manchester decoder The decoded bits are fed into the frame controller which keeps track of position in the packet possible errors and decides between long and short packets used in Mode S transmissions The decoded packets are fed into a FIFO which is connected to an UART module Through the UART data is sent to the ARM computer for analysis error correction and logging The timing recovery unit will only be BX18 ARCA SED v5 0 12JAN15 docx Page 46 EupoLAUNCH Student Experiment Documentation implemented if it is needed Previous experiments show that t
53. n external monitor for the ground station e Tests to be performed before the launch e The system should be powered on and running in its normal mode e Test if ADS B messages are received see the flashing LED at the experiment box e All messages from the experiment scientific data and housekeeping data will be analysed to ensure a fully operational experiment e An external power supply is required e Internet access via cable or WIFI BX18_ARCA_SED_v5 0_12JAN15 docx Page 70 EupoLAUNCH Student Experiment Documentation 6 1 5 Experiment Shipping Both built experiments were shipped via a spedition to Kiruna During IPR this idea was mentioned by ZARM They organized everything with the spedition The experiments and all other needed stuff were packed into an aluminium box Zarges box with the dimension of 80x60x60cm As discussed at IPR the parcel was picked up in Jena on 19 September 2014 Additional equipment for experiment testing in Kiruna was either be brought in the flight baggage or shipped in the parcel 6 2 Preparation and Test Activities at Esrange The following tests should be possible after the experiment is mounted in the gondola and power is applied Power is applied Power LED LED1 green comes on 1 min later Alive LED LED1 red blinks periodically ca 1 Hz E Link is connected Link LED LED2 green is on E Link data is transmitted received Act LED LED2 red flashes Stimulatio
54. n with bladeRF test transmitter RX LED LED3 red flashes also if ADS B is received from planes To verify that the experiment is working in phases where E Link is not available before start of the balloon visual inspection of the LEDs is sufficient For testing the experiment out on the launch pad before launch preparations have begun a portable power supply was built This way the experiment especially the RF receiver functionality can be tested far from EM interference sources 6 3 Timeline for Countdown and Flight The experiment will capture data from the release of the balloon till the end There is no special timeline planed During the flight every 5min a new file will be written to reduce the risk of data loss during the flight caused by e g power failures Before launch and during rollout at Hercules the antenna will be fixed to the gondola structure to prevent a damage Before the launch we have to release the antenna from the gondola premounting Because of that we need a late access to the experiment and the possibility to speak to the ARCA ground station via radio communication After the release of the antenna there have to be 2m space between gondola and ground to prevent a damage of the antenna BX18 ARCA SED v5 0 12JAN15 docx Page 71 E UROLAUNCH Student Experiment Documentation ARCA would like to capture data in high altitude as long as possible at daylight This means around 2h at flight l
55. nt aluminium sheets and multiple L sections which are screwed together and attached to the experiments mounting rails To ensure easy access to the experiment setup the top is made of a separate aluminium sheet To protect the electronics inside the box against temperature influence the experiment will be using anti static Styropor parts cut in shape to insulate the box and to support any cabling to the front panel The PCBs are fixed by bolts to the base of the box which are guided through the Styropor This mounting technique is very weight efficient and guards efficiently against shock and temperature transients as Styropor has high thermal resistance BX18 ARCA SED v5 0 12JAN15 docx Page 30 EurOoLAUNcH Student Experiment Documentation Mounting of the PCBs is visualized in the following image ANSYS R14 5 Academic ey 0 000 D 100 m x aaa 1 0 050 Picture 2 PCB mounting in the experiment case The experiments mounting rails provide elongated holes to account for any tolerances All Screws will be secured by lock washers where applicable nuts and thread lock adhesive as suggested in training week To ensure maximum safety all sharp edges will be removed in the manufacturing process In picture 3 you can see the ready built case for the experiment Picture 3 Case BX18 ARCA SED v5 0 12JAN15 docx Page 31 EurRoLAUNCH Student Experiment Documentation Soc Note To avoid
56. of the IPR SED is directly in the middle of our exam phase we were not able to successfully fix all mentioned problems This fact was mentioned to ZARM and acknowledged Interim Progress Review IPR IPR was held at EAH Jena with all team members from Jena and Julia Gr nhage Dieter Bischoff and Simon Mawn from ZARM Also attending was Prof VoB our mentor from university during this project The overall experiment progress was reviewd and last good advices concerning the mechanical design practise were given All open topics were discussed with satisfying results Experiment Acceptance Review EAR The EAR took place in our university in Jena During EAR all team members were involved and could participate Also Prof Vo our mentor during the whole project took part during the meeting with the experts from ZARM BX18 ARCA SED v5 0 12JAN15 docx Page 84 EupoLAUNCH Student Experiment Documentation After a discussion about the building process of the experiment and a detailed talk about the upcoming launch campaign we made a demonstration of the working experiment BX18 ARCA SED v5 0 12JAN15 docx Student Experiment Documentation Page 85 E UROLAUNCH APPENDIX B OUTREACH AND MEDIA COVERAGE After the PDR and trainings week in Esrange we wrote a press release together with our university press office It was published in the following newspapers and their websites Our university website htt
57. ositionsdaten erlaubt Rechtsanwalt Michael Riedel DG2KAR http www lawfactory de PDF FUNKAMATEUR 2010 03 pdf ARCA FPGA github repository http www github com thasti arca fpga BX18 ARCA SED v5 0 12JAN15 docx Page 83 E UROLAUNCH Student Experiment Documentation APPENDIX A EXPERIMENT REVIEWS Preliminary Design Review PDR PDR took place in Kiruna Sweden All team members except Johannes Willenb cher have been there Most feedback received from the PDR board was positive but the following problems were identified Heating should not be necessary as planned It would be more sensible to invest in better thermal insulation Having 5 people in the team could prove being not enough It could be hard to collaborate well if one team member is from a university far away e FPGA design is a high risk factor because it constitutes a single point of failure We tried to overcome these problems The thermal concept was reworked and is in stable condition For an experiment of our size five people seem to be enough work is progressing well For eliminating the point of failure FPGA design a backup plan using a commercial ADS B receiver was derived Critical Design Review CDR CDR took place in Noordwijk Netherlands All team members have been there The SED was described as containing too little information lacking some experiment details We tried to address this problem until IPR but as the issue date
58. p www fh jena de fhi fhjena de presse ap Seiten 140409 Wissenschaftliche Feu ertaufe aspx JenaTV http www jenatv de wissenschaft Wissenschaftliche Feuertaufe 21338 html Jenapolis de http www jenapolis de 2014 04 09 studenten der fh jena entwickeln raumfahrttechnologie TLZ Friday 11 April 2014 TLZ is a local newspaper for Jena Jenapolis 07 Januar 2015 http www jenapolis de 2015 01 07 ballonexperiment auf schwedischer raumfahrtbasis BX18 ARCA SED v5 0 12JAN15 docx Page 86 EupoLAUNCH Student Experiment Documentation APPENDIX C ADDITIONAL TECHNICAL INFORMATION All Schematics and technical drawings can be found in the project repository as including them here would degrade quality significantly As the schematics are relatively complex they wouldn t be readable in this document BX18 ARCA SED v5 0 12JAN15 docx Page 87 EuroLAUNCH Student Experiment Documentation APPENDIX D REQUEST FOR WAIVERS BX18 ARCA SED v5 0 12JAN15 docx
59. r university e We presented the REXUS BEXUS program in a Masters course for Space Electronics at EAH Jena and got in contact with possibly interested people e We presented the REXUS BEXUS program to pupils of tenth grade from Friedrich Schiller Gymnasium Zeulenroda e We are going to give an interview to our local university student radio station Campusradio Jena e We created a poster about the launch campaign in Kiruna which is shown to everyone in our university department e A newspaper article about the ARCA project REXUS BEXUS and the launch campaign was published at Jenapolis a regional news website e At the website of our university department a picture gallery was created 3 5 Risk Register Risk ID TC technical implementation BX18 ARCA SED v5 0 12JAN15 docx Page 24 EuROLAUNCH A DLR and SSC cooperatior Student Experiment Documentation MS mission operational performance SF safety VE vehicle PE personnel EN environmental Probability P A Minimum Almost impossible to occur B Low Small chance to occur C Medium Reasonable chance to occur D High Quite likely to occur E Maximum Certain to occur maybe more than once Severity S 1 Negligible Minimal or no impact 2 Significant Leads to reduced experiment performance 3 Major Leads to failure of subsystem or loss of flight data 4 Critical Leads to experiment failure or create
60. ransport to Kiruna Table 5 5 EMC test Test number 4 Test type EMC test Test facility EAH Jena GTEM chamber Tested item ARM Board baseboard front end the whole experiment system level test Test level procedure and duration Acceptance test 1h Test duration campaign Test campaign date First half of September 2014 Test completed Done see report 5 3 6 Table 5 6 power consumption test Test number 5 Test type Power consumption test Test facility EAH Jena Tested item The whole experiment BX18 ARCA SED v5 0 12JAN15 docx Page 54 EuROLAUNCH A DLR and SSC coop Student Experiment Documentation Test level procedure and duration Qualification test Test campaign 10min duration Test campaign date 27 08 2014 Test completed Done See test protocol 5 3 5 Table 5 7 Experiment size test Removed Table 5 8 Weight test Test number 7 Test type Weight measurements Test facility EAH Jena Tested item The whole experiment Test level procedure and duration Qualification test Test duration campaign Test campaign date First week of September 2014 Test completed Done see test protocol 5 3 7 Table 5 9 Experiment E Link test Test number 8 Test type E Link test Test facility Esrange Tested item Th
61. responding FPGA This bug was fixed with a 5mm long wire bridge at the PCB After fixing these points the electronics worked always reliable until the end of the project including all absolved tests 7 4 A Software As software development was finished long enough before launch campaign we were able to conduct many software tests on flight software This combined with an open git based software development model led to very well tested software that exposed no problems during flight All communications worked as expected and no crashes or other difficulties could be noticed By design each software module had its own watchdog which would have reset it eventually and log every crash The FPGA code proved also to be very reliable eliminating needs for additional security measures 7 4 5 Thermal The measured temperature trend is shown below BX18 ARCA SED v5 0 12JAN15 docx Page 78 EuroLruncHh RR ond 88 cooperation Student Experiment Documentation FPGA ADC ETH PCB Inside Outside Temperature C 0 50 100 150 200 250 300 350 400 Time min Picture 14 Recorded airplane tracks during the flight Before launch outside temperatures were at approx 0 C and a thermal steady state was reached before launch at 08 49 UTC While ascending the temperatures outside dropped to 40 C quite fast caused by the cooler air in higher altitudes Interestingly the
62. s minor health hazards 5 Catastrophic Leads to termination of the project damage to the vehicle or injury to personnel Table 3 1 Risk Register ID Risk amp consequence if not P S PxS Action obvious TC10 Components are damaged during A 1 Redundant test components MS10 Deleted after PDR MS20 EM interference by e g other C 2 Other experiments must be sure that their experiment is not transmitting RF at this frequency experiments on the ADS B frequency 1090 MHz MS30 Loss of connection to E Link B 1 Store data to flash during flight MS40 Water landing A 3 The data storage shall be water resistant data is transmitted to ground support while the experiment is in flight MS50 Short power outage A 1 Electronics shall reboot automatically MS60 Too few airplanes to receive A 2 Prefer a day flight to have a higher chance to receive airplanes BX18 ARCA SED v5 0 12JAN15 docx Student Experiment Documentation SF10 Loss of the Antenna Page 25 ADLR and SSC cooperation EuROLAUNCH The antenna should have a good mounting at the gondola BX18 ARCA SED v5 0 12JAN15 docx Page 26 EupoLAUNCH Student Experiment Documentation 4 EXPERIMENT DESCRIPTION 41 Experiment Setup The ARCA experiment will consist of a radio frequency receiver listening on the ADS B
63. ted by FSPLmax Ppiane Pmin 146 4 dB By changing the free space path loss equation to the distance the maximum reception distance can be estimated dmax 460km As packet decoding was observed to be working well at less than 100mV input swing and bigger airplanes tend to have transmission power of up to 500W even planes further away might be heard BX18 ARCA SED v5 0 12JAN15 docx Page 36 EupoLAUNCH Student Experiment Documentation To approximate RF out of band rejection the datasheet of the input filter gives an impression N Na 990 1010 1030 1050 1070 1090 1110 1130 1150 1170 1190 Frequency MHz Figure 4 TA0232A transfer function As GSM and primary radar applications were expected to be the biggest problematic jammer above urban areas the filter transfer function outside the pass band has to be considered For P E R GSM operating downlink at up to 960MHz stop band attenuation of 50dB to 60dB is achieved As one of these filters is applied before every amplifier section attenuation worst case is about 85dB This is believed to be enough margin for the receiver to work properly Regarding the in band input overloading receiver defect concerns the following calculation was done The nearest transmitter is the BEXUS on board ATC transponder located about worst case 10m distant from the ARCA receiver antenna The ATC transponder transmissions were estimated every 6 seconds for ims
64. temperatures began to rise again approx 1 hour after launch This was most probably caused by the increasing solar radiation experienced In the late float phases we reached equilibrium temperatures of little below 0 C on the case outside and 20 C inside the experiment All measured temperatures are well within operating conditions To be honest we did not take solar loads into consideration when making thermal approximations as none of the former BEXUS flights we looked into had sun exposed experiments From our experience solar heat radiation can clearly be taken into account for thermal design of a BEXUS experiment when conducting a day flight Luckily we developed our experiment to withstand both day and night flight conditions so were not affected in problematic Ways 7 5 Lessons Learned 7 5 1 Antenna The antenna was the part that caused the most severe trouble BX18 ARCA SED v5 0 12JAN15 docx Page 79 EuroLAUNcH LR and SSC cooperat Student Experiment Documentation After the flight we only got back the cable with the first segment of the antenna wire and later the housing pipe Many speculations were made about the reason of that One option is that it was torn apart in trees during landing But that doesn t correlate with the data dropout during ascend Another option and the most probable cause is in the antenna construction itself The segments were movable inside the protecting pipe And maybe dur
65. ter Software for visualizing the planes received by the experiment payload data BX18 ARCA SED v5 0 12JAN15 docx Page 49 E UROLAUNCH Student Experiment Documentation PlanePlotter data is input via the TCP IP Interface of the remote experiment control software BX18 ARCA SED v5 0 12JAN15 docx Page 50 EupoLAUNCH Student Experiment Documentation 5 EXPERIMENT VERIFICATION AND TESTING 5 1 Verification Matrix Table 5 1 Verification table ID Requirement text Verification Status Test No The experiment shall F2 detect data from T R Done 9 airplanes ADS B F3 Removed ra The received data shall R Bang _ be saved on a flash card The experiment shall P2 only receive data at a A S Done frequency of 1090MHz The experiment should P3 have a storage capacity H Done of 16GB The experiment shall be able to receive a minimum of 5 messages per second P4 T R Done 9 The experiment shall P5 receive data with a data A Done rate of 1Mbit s The experiment shall work at the temperature DI profile of the BEXUS A T Done 2 balloon The experiment shall D2 work at the vibration T Bars profile of the BEXUS balloon The experiment shall not D3 harm the gondola and T Done 4 other experiments D4 1 The experiments shall be R T Done 8 designed to use the E BX18 ARCA SED v5 0 12JAN15 docx Student
66. test Test facility Friedrich Schiller University Jena or Ernst Abbe University for applied science EAH Jena Tested item The whole experiment system level test Test level procedure and duration Acceptance test 24h Test campaign duration Test campaign date First week of September 2014 Test completed It was difficult to arrange an appointment for this second test and the component vacuum test went very well this test was skipped Table 5 3 Thermal test Test number 2 Test type Thermal test Test facility EAH Jena Tested item ARM Board baseboard RF front end component test Later the whole experiment system level test Test level procedure and duration Acceptance test 3h Test duration campaign BX18 ARCA SED v5 0 12JAN15 docx Student Experiment Documentation Page 53 ADLR and SSC EuROLAUNCH Test campaign date First half of September 2014 Test completed Done see test report 5 3 1 and 5 3 2 Table 5 4 Mechanical test Test number 3 Test type Shock test Test facility EAH Jena Solid surface Tested item The whole experiment system level test Test level procedure and duration Qualification test 1s Test duration campaign Test campaign date First week of September 2014 Test completed Not done because the experiment worked well after the t
67. ties 4 2 2 Electrical The experiment needs connections to the power system We will use the recommended connector type MIL C 26482P with 8 4 insert arrangement MS3112E8 4P As we want to be able to use the up downlink of the E Link system there will be an Ethernet connector Amphenol RJF21B with insert code A To see if different subsystems of the experiment are running there will be 3 5mm LEDs mounted at the front panel e Dual LED o Green Power experiment is connected to a power source o Red Alive the on board computer is running This will be indicated with a flashing of the second LED e Dual LED Il o Green The experiment is connected to Ethernet and a link is established o Red Data is transmitted received via Ethernet e Single LED o Red ADS B data packet was received Flashing All LEDs are mounted in LED mounts to increase visibility in bright light conditions 4 2 3 Radio Frequencies The experiment will use the standard Mode S ADS B frequency of 1090MHz As the antenna needed for reception will be mounted outside the gondola there will be an N female connector next to the power and network connectors on the front panel The Antenna will be a collinear antenna consisting of at least seven stacked elements giving a length of about 1m BX18 ARCA SED v5 0 12JAN15 docx Page 28 EupoLAUNCH Student Experiment Documentation The use of this frequency was discussed again at CDR as it usually is
68. tions Add abbreviations to the list below as appropriate and delete unused abbreviations ADS B AIT ASAP BO CDR COG CRP FPGA DLR DSP EAT EAR EIT EPM ESA Esrange ESTEC ESW FAR FST FRP FRR GSE HK H W ICD I F IPR LDO LED LNA LO Automatic Dependent Surveillance Broadcast Assembly Integration and Test as soon as possible Bonn DLR German Space Agency Critical Design Review Centre of Gravity Campaign Requirement Plan Field Programmable Gate Array Deutsches Zentrum f r Luft und Raumfahrt Digital Signal Processing Experiment Acceptance Test Experiment Acceptance Review Electrical Interface Test Esrange Project Manager European Space Agency Esrange Space Center European Space Research and Technology Centre ESA NL Experiment Selection Workshop Flight Acceptance Review Flight Simulation Test Flight Requirement Plan Flight Readiness Review Ground Support Equipment House Keeping Hardware Interface Control Document Interface Interim Progress Review Low Dropout Voltage Regulator Light Emitting Diode Low Noise Amplifier Lift Off BX18 ARCA SED v5 0 12JAN15 docx Student Experiment Documentation LT LOS Mbps MFH PCB PDR PST RBF RTC SED SNSB SNR SODS SOE STW S W TBC TBD WBS ZARM Page 81 E UROLAUNCH Local Time Line of sight Mega Bits per second Mission Flight Handbook Printed Circuit Board electronic card Preliminary Design Review Paylo
69. tus data and ADS B frames and to talk to the health status monitor See 4 9 for supported uplink commands Frame logging module This software module listens to the decoded frames from the FPGA coming in over the ARM serial port It logs all incoming frames into an appropriately uniquely named file for later analysis including timestamps Via inter process communication the incoming frames and statistic information is communicated to the uplink downlink module Health status monitor module This module will monitor the different temperature sensors placed on the PCBs of the experiment It is also able to issue reset commands to the internal watchdog and the FPGA to handle software failures Watchdog The watchdogd software of Linux is used to continually send activity information to the watchdog If for example because of a software failure this information is missing for too long the system automatically performs a hard reset This will hopefully help recovering from unforeseen software conditions BX18 ARCA SED v5 0 12JAN15 docx Page 47 E UROLAUNCH Student Experiment Documentation Ethernet communication The connection between the experiment and the ground support is done via Ethernet utilizing the E Link system Data is transmitted using TCP IP Usage of TCP is justified for two main reasons The connection has to be initiated by ground support which makes sure data is only sent when ground support equipment is
70. upoLAUNCH Student Experiment Documentation ABSTRACT In the modern world the aircraft is a common way of transportation With thousands of flights every day of course the need for tracking planes monitoring their position and health status arises At the moment most airplanes are only tracked in densely populated areas The main goal of the experiment is to show which advantages an aircraft based ADS B surveillance system could have using a stratospheric balloon for demonstration and evaluation One experiment goal is not to resort to using pre built electronics but instead develop verify and produce the different parts of the experiment ourselves The receiver will listen to Mode S aircraft traffic decoding DF17 position reports and log them on board as well as downlink them to the ground station There the data will be plotted by user interface software for a quick look analysis and be saved for careful interpretation afterwards BX18 ARCA SED v5 0 12JAN15 docx Page 11 E UROLAUNCH Student Experiment Documentation 1 INTRODUCTION 1 1 Scientific Technical Background In the modern world the aircraft is a common way of transportation With thousands of flights every day of course the need for tracking planes monitoring their position and health status arises As flight numbers increase there is a chance that people tend to lose track of flights and for example a crash may not be noticed instantly Our
71. xperiment Documentation AOL and SS cooperation 2 EXPERIMENT REQUIREMENTS AND CONSTRAINTS 2 4 Functional Requirements F1 Removed F2 The experiment shall detect data from airplanes ADS B during the whole flight F3 The experiment shall distinguish between different airplanes F4 The received data shall be saved on a flash card 2 2 Performance requirements P1 Deleted P2 The experiment shall only receive data at a frequency of 1090MHz P3 The experiment shall have a storage capacity of 16GB P4 The experiment shall be able to receive a minimum of 5 messages per second P5 The experiment shall receive Mode S ADS B data with a data rate of 1Mbit s 2 3 Design Requirements D1 1 After CDR deleted D1 2 The experiment shall be designed to prevent the electronics from temperatures below 20 C to ensure safe operating conditions D2 The experiment shall work at the vibration profile of the BEXUS balloon D3 The experiment should not harm the gondola and other experiments D4 1 The experiment must be designed to use the E Link downlink D4 2 The experiment must be designed to use the E Link uplink D5 The experiment shall not use more than 0 5 Ah of the gondola battery D6 The experiment shall not be air tight and be equipped with holes D7 The experiment shall not be heavier than 2kg D8 The experiment box shall not be bigger than 0 2m x 0 2m x 0 2m D9 The receiver should decode the incoming data at a fr

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