Home

- Murdoch Research Repository

1. Once after several successful autonomous flying missions had been conducted it was deemed that the Ardupilot sufficient and research began into identifying a more application appropriate airframe 3 1 Airframe Selection The desired attributes of an airframe to be used for this application include efficient flight and sufficient payload capacity while maintaining transportability and durability Many COTS airframes were researched and time constraints meant that designing a custom airframe was unrealistic While many models were short listed a platform called the Foamaroo 23 shown in Figure 8 was identified that had a number of beneficial features e A hybrid foam fiberglass construction making it light weight yet still being durable e A mostly hollow 29 inch 73 66cm long cylindrical fuselage with a 3 5 inch 8 89cm internal diameter leaving a large payload space e Detachable wings for ease of transport e An elevon configuration with only two control surfaces for simplicity and ultimately less points of failure e A pusher configuration where motor is behind the airframe making it inherently safer during a collision as the propeller is less likely to make direct contact with the other body Like the Funjet the Foamaroo uses a lithium polymer battery to power the 3 phase brushless DC motor and on board electronics In a typical configuration the manufacturer quoted a cruising speed of approximately 15 m s and an en
2. 8x Slr iR HIA CO Mas Wide Assembly 4 Mae o e a 7x4 e Mates E san Q Mate Selections a E y rr al K Coincident gt Parallel A Y Perpendicular ES Tangent el Concentric 3 Lock je 100mm fl WH d Advanced Mates SI SA sl Mates R Py Servo Tilt Angle Futaba S9070SB Assembly lt 3 gt CQ Maxi Options R Add to new folder d Show popup dialog J Show preview __ Use for positioning only Ws 1 Model Motion Study Fold Ducts Motion Study HD24MP Motion Study DSLR 1 Motion Study 7 Nx Design Study 1 Figure 40 Gimbal size constraints Knowing the sensor size of the camera and its focal distance with the 16mm lens it was possible to include the cameras field of view FOV within the model Figure 41shows an earlier design where it was possible for the CyberQuad s ducts to fall within the FOV This was corrected in the next revision solidworks y gt e Edt Mem inert Tools Window Heb JOETA E a TG E pen Wide Assemb V16 g H E K SZ eh e ee ee ae 2 5 ar Dm C Gemen eeneg Component idian Femues Geometry atea gen Comporerta tuf LAS 0 3 E e tele WI gc al aag al a Figure 41 Solidworks motion study 31 Solidworks can conduct motion studies which accurately simulate and analyse the motion of an assembly while incorporating the effects of Motion Study elements including forces springs dampers and friction 4
3. MKGPXTool Online Available http www mikrokopter de ucwiki en MKGPXTool Accessed 2012 September 48 aaroncake How To Solder Soldering Tutorial Online Available http www aaroncake net electronics solder htm Accessed October 2012 49 Mikrokopter WaypointGenerator Area Online Available http www mikrokopter de ucwiki en WaypointGenerator Area Accessed September 2012 50 Hypr3D About hypr3D Online Available http www Hypr3D com whatwedo Accessed 2012 51 F Schmidt GeoSetter Online Available http www geosetter de en Accessed October 2012 52 A L Steve Harwin AN ACCURACY ASSESSMENT OF GEOREFERENCED POINT CLOUDS PRODUCED in International Archives of the Photogrammetry Remote Sensing and Spatial Information Sciences Volur XXXIX B7 Melbourne 2012 53 S R U S J Z M J U Niethammera OPEN SOURCE IMAGE PROCESSING TOOLS FOR LOW COST UAV BASED LANDSLIDE INVESTIGATIONS in International Archives of the Photogrammetry Remote Sensinc and Spatial Information Sciences Volume XXXVIII 1 C22 Zurich 2011 54 W Mayr UAV MAPPING A USER REPORT in International Archives of the Photogrammetry Remote Sensing and Spatial Information Sciences Zurich 2011 55 J F H J M T P R G D H Diego Gonzalez Aguileraa 3D MODELLING AND ACCURACY ASSESSMEN OF GRANITE QUARRY USING in ISPRS Annals of the Photogrammetry Remote Sensing and Spatial Informatio
4. cr Y Murdoch UNIVERSITY Unmanned Aerial Vehicle Payload Development for Aerial Survey ENG460 Engineering Thesis Nick Sargeant A report submitted to the School of Engineering and Energy Murdoch University in partial fulfilment of the requirements for the degree of Bachelor of Engineering Abstract Aerial imaging is key part of remote sensing and surveying however traditionalacquisition methods such as satellite imagery and manned aircraft suffer from some limitations namely high capital operational and personnel costs slow and weather dependent data collection restricted manoeuvrability limited availability limited flying time low ground resolution 1 Unmanned Aerial Vehicle have gained increasing attention in recent years as technological advancements such as sensor minimization have made them a viable alternative for aerial photogrammetry applications This report outlines the design and development of an Unmanned Aerial Vehicle suited for aerial survey The first stage of the project involved a comprehensive literature review of existing research and evaluation of existing commercial solutions Existing commercial solutions such as the Gatewing X100 have proved capable in industry however a number of limitations were identified the most prominent being that the optical payload they carry is rigidly coupled to the airframe As weather conditions become more adverse and wind gusts buffet aircraft the cam
5. Figure 51 ArduCopter roll axis stabilization control loop 45 In addition to the nested control loop structure interacting control loops and non linear dynamics make developing accurate mathematical models of the system very difficult and well beyond the scope of this project Simplified attitude only modelling has been conducted in the paperEstimation and Control for an Open Source Quadcopter 46 however 38 this research was found to have limited practical use for tuning the control loops of the CyberQuad As such tuning was conducted on oscillations and listening for oscilla line by visually and audibly by looking for attitude tory motor speed changes monitoring the aircraft s flight performance Additionally when the ground station is connected to the CyberQuad via telemetry link the Scope function within MikroKopter Tool Figure 52 allows for near real time viewing of many of the autop outputs In the Scope tab the indivi of use included altitude attitude a WEE o HO O pete lots parameters including raw sensor data and control dual parameters can be selected for display Parameters nd motor speeds Status Interval scope Motortest M AngleNick scape Motomest m Fuereware updete Terminal W Firmware update amp Terminal M AngleRoll EI AccNick i Esport com em Ex M AccRoll Figure 52 MK Tools Scope function Various control loop parameters can be a
6. Photos Console i Due to the strong winds the aircraft was at its maximum pitch limit of 30 for much of the flight As such data collection suitable imagery for processing using a non stabilized gimbal would not have been possible 57 7 Future Work In the near future it is hoped that the GCP survey data can be obtained and used for processing the test site This should definitively prove one of the original hypothesesof the research using a stabilized gimbal allows for more efficient flight plans as a lower level of overlap is required Additionally the data generated from processing should allow an estimated function of overlap vs model accuracy to be determined allowing future flight plans to be optimized Development of the CyberQuad payload will continue into the future with the aim of producing a commercially viable product A minor hardware revision of the mount will be conducted to strengthen the y bracket but at the same time attempt to reduce the width of the gimbal giving more clearance from the CyberQuad s ducts The HDMI video out will also be re addressed Research will also be undertaken with the aim to develop surveying payloads that use imaging systems that capture radiation beyond the visible spectrum Interest has been expressed by the renewable energy engineering department at Murdoch University to conduct a trial survey capturing long wave infrared thermal imaging data of solar panels to check fo
7. Poti abbreviated from potentiometer refers to a channel which can be assigned to a control function The first four channels are used for throttle yaw nick pitch and roll control Other channels are assigned to additional features such as the mode switch selecting autonomous navigation To allow an UAV operator to manually trigger photos using the controller a momentary switch on the UAV controller was assigned to a spare RC channel in this case channel 11 The RC channel is then is the assigned to MikroKopter channel POTI 7 in the Channels tab as demonstrated in Figure 48 Function Channel Function Channel GAS 1 POTI3 YAW 8 v POTIA NICK E POTIS i ROLL 2 v POTIb POTI POTI2 Motor safety switch Sensitive receiver signal validation Figure 48 Waypoint trigger configuration POTI 7 is then bound to Servo 3 in the camera tab shown in the Figure 49 Servo 3 Servo 4 P1 5 1 EP 6 1 Figure 49 Waypoint trigger configuration cont 37 When planning a flight mission using MikroKopterTool OSD which is detailed in the next section there is a field WP Event that allows a switching output to be toggled when a waypoint is reached This output was used to trigger the camera at each waypoint The behavior of the output is configured in the Output tab As the trigger is only activated once per waypoint only one box is selected and to ensure the interface c
8. World Geodetic System 1984 Coordinate system WGS 84 Images E GCPs a EI Processing areas Orthomosaic area Latitude 32 215265 Longitude 115 770830 Figure 68 Pix4D Cloud GUI Once the data has been uploaded it is processed at no cost and a reconstruction report is automatically generated providing a quality and accuracy assessment If a user is satisfied with the result the data can be purchased and downloaded The following options are available e 2D orthomosaic and Google Map tiles e 3D orthomosaic Google Map tiles DEM and Point cloud 60 euros Free trial 2 Wh 67563 240 euros Free trial 2 wh covpueel Figure 69 Pix4D processing options 51 It was planned to use Pix4D extensively as the software did not require a powerful machine and the reports which were generated at no cost could be used to evaluate the each models accuracy 6 Phase Four Testing and Case study 6 1 Test Site A safe and convenient test site was identified in close proximity to Cyber Technology s offices Using the flight planning spread sheet to generate the flight parameters six flights were conducted at 100m altitude and overlaps of 80 60 and 40 To test the effectiveness of the active stabilization repeat flights were conducted at a given overlap with gimbal stabilization enabled and then repeating the same flight with the stabilization disabled such that the gimbal remained fixed During each flight the aircraft was
9. which significantly reduces processing time Once a computer was sourced that had sufficient processing power and a trial licence obtained models were successfully generated without GCP data Due to the system requirements for this software and the processing time required using the available computer PhotoScan was not extensively utilized 5 2 2 3 Pix4D Cloud Pix4D Figure 68 is a commercial industry grade photogrammetric solution recommended by both the Swinglet Cam and Gatewing for processing imagery from their products Like Hypr3D Pix4D Cloud is a cloud service meaning images are uploaded to and them processed by remote servers To use Pix4D Cloud Windows compatible software called to Pix4UAV must be installed onto a computer Using the software a project is created and images are 50 added to the workflow Ground control points can be optionally added and if only a sub section of the captured area is required the smaller area can be masked Once project configuration is complete the data is uploaded to the remote servers for processing configured before the data is uploaded to the cloud P4 Pix4UAV Cloud 1 2 stockpile Project Georeference Process Help ES O nokia maps x Y Project summary Project Name stockpile Workspace E Users Sarge Documents pix4uav Datum World Geodetic System 1984 Coordinate system UTM Cloud processing Uploaded yes Images Number selected images 47 Datum
10. 12 A 532 12 ES 32 2 12 Soe f S32 12 E115 weeny Sua a tetra dr Sara de dr da de tr TE rt tete LL DSC00421 DSC00422 DSC09423 DSC00424 B a a B E EXT 10 5 23 10 2012 6 11 1 EG 11 2 SE 11 4 23 10 2012 6 20 1 23 10 2012 6 20 3 23 10 2012 6 20 4 5 4 DSC00425 DSC00427 12 som 15 4 32 12 E1 Ce east Ce P S32 1 En 32 12 sq 15 532 12 Sue 15 d 532 12 115 orato Saro every eeeee erre weree Laa 47 Images 47 with Geo Data 1 selected e Image Preview SBS Favorite ege iM 4 b d Fit FitAutometically 100 Center Search Search Coordinates SS Tracks we DX Figure 67 GeoSetter GUI 5 2 2 2 PhotoScan Agisoft PhotoScan Professional edition is a commercial grade software solution that can produce high resolution georeferenced orthophotos detailed DEMs and textured polygonal models PhotoScan was identified during the literature review as it has been used by many researchers for UAV applications PhotoScan is computationally intensive with the recommended system requirements being e Windows XP or later 64 bit Mac OS X Snow Leopard or later Debian Ubuntu 64 bit e Intel Core i7 processor e 12GB of RAM PhotoScan can use a computer s graphics processing unit GPU in addition to the central processing unit CPU for hardware accelerated processing
11. CyberQuad s ducts 35 Parameterset 3 Easy g Sele Configuration Stick Looping Altitude Camera Navi Ctrl Nawi Ctrl 2 Output Misc Gyro User Coupling Mixer SETUP Easy Setup Nick Roll Servo control h28 h28 Nick compensation fol be invert direction lv invert direction Servo min mw o ZG bn o y servo max Sa 3 ban lt servo filter pb SH bh lt 0 OFF Servo refresh rate 4 al 2 fastest Manual control speed 60 H 1 fastest Servo 3 ke d Sa Servo 4 25 Servo 5 125 El 4 i 5 ep Bes 7 1 Bam P5 9 1 Bro 10 1 EP 1 Bre 12 1 GC DS Figure 47 Mk Tool gimbal configuration 4 8 Camera Triggering Configuration Configuration of the camera trigger is completed in the Channels Output and Camera tabs of MK Tools Settings window It was desired to have the camera trigger activated automatically when flying a mission but to also allow an operator to manually trigger the camera using the hand controller MikroKopter s configuration versatility makes this configuration possible although it is a complex process 36 A summary of the is as follows Function Trigger Event PotiChannel Physical Output Manual Trigger RC channel 11 oo 7 Servo 2 Auto Trigger Switch Output 1 Table 4 Trigger configuration summary An attempt at documenting this configuration is now made In the MikroKopter configuration
12. FarhMagqnet s 9 mpl e gt MKGPS gt MK3Maq FO Seer Magnet x status Interval Scope S Magnet Magnet Z Flight Ctrl a Load Les lal Export csv Distance M Distance E Boil http www MikroKopter com GPS_Nick 0 Navi Ctrl GPS_Roll les Gi Exit EE MikroRopter To0147 28d cl waw mikrokopier de Figure 55 Sporadic magnetometer readings The source of the fault was found to cold solder joint resulting in an intermittent break in connection between the IC and the circuit A cold solder joint can occur when not enough heat is applied to the component board or both A cold joint is brittle and prone to physical failure It is also generally a very high resistance connection which can affect the operation of the circuit or cause it to fail completely 48 The magnetometer was identified on the Navi Ctrl board and using a hot air rework station the chip was the re soldered to the PCB Following this the unit was again bench tested using MK Toolsand found to be working as expected 41 5 Phase Three Mission Planning data collection and processing In a typical surveying mission project parameters such as thesize of the area being surveyed and the desired ground resolution called ground sample distance GSD are used to generate a flight plan for the UAV The flight plan is usually a series of waypoints typically ina lawnmower pattern The UAV autonomously conducts the flight plan and capture
13. GPS Data Fil Synchronize with Tracks in Current Directory Synchronize with Visible Tracks 5 Synchronize with Data File Synchronize with a Directory containing Data Files E Users Sarge Desktop LOG 20121023 GPX Assignment of Found Positions Assign Exactly to Found Position 5 Interpolate Regarding Shoot Time With Last or Next Position Synchronize Heading Data if Available Maximum Time Difference between Taken Dates and Trackpoints seconds o C Do notuse Track Points in Future Time Adjustment Since track files recorded by GPS receivers contain the date and time in UTC format nearly Greenwich Mean Time GMT possibly the date time of your images have to be adjusted by adding or subtracting a time value depending for example on the time zone in which the images were taken Furthermore the images maybe were taken while daylight saving time which you have considered when adjusting the dock of your camera Please use 1 of the following 4 options below to adjust the date time of your images Use this option if you have recorded a waypoint together with taking an image Result see below Hours Minutes Seconds Time will be adjusted by o DEI Reset X E k 4 Add Offset Values to Taken Date Figure 66 Image synchronisation with GeoSetter Additionally once synchronized GeoSetter displays the photos embedded within Google Maps Figure 67 which gives a first pass check to see if there was sufficient photo coverag
14. Safety Authority CASA as having a maximum takeoff weight of 150kg Due to their size and ease of mobilization UAV s are particularly surveying sites that are in the order of low km especially if the site had to be surveyed at a regular interval An example of such a site is a stockpile Figure 4 illustrates the optimum conditions for different surveying techniques Accuracy mm 10 10 102 10 1 10 102 industria metrology 103 interfero Object area size 2 3 5 1 10 10 10 10 m2 Figure 4 Photogrammetric technologiesand their application 12 While using Small UAVsystems with consumer type digital camera for mapping and photogrammetry has been successful one of the largest problems of existing systems has been the lack of active stabilization of the aerial camera This results in tilted pictures caused by wind influences or instability of the platform Furthermore to ensure complete photogrammetric block configuration the end lap and the side lap have to be relatively high 70 70 compared to standard aerial surveys 13 2 2 1 Advantages of UAVs Satellite imagery manned aircraft and other conventional surveying techniques suffer from some limitations namely high capital operational and personnel costs slow and weather dependent data collection restricted manoeuvrability limited availability and low ground resolution 1 Small UAV s have far lower costs and due to flying at
15. and Energy at Murdoch University It is designed to provide exposure to the world of engineering design or research through the study of a substantial project in one or more areas of specialisation within the School of Engineering and Energy 9 As this is an engineering thesis that deals with topics such as aerial photography and UAVsthat may be unfamiliar to the reader a detailed background is now given 2 1 Photogrammetry The term aerial survey is synonymous with aero photogrammetry Photogrammetry is a measurement technology in which accurate measurements are determined from stereoscopic images Photogrammetric processing software builds on the basic concept of triangulation and uses advanced computer vision techniques such as Bundle Adjustment 10 and Structure from Motion 8 to generate highly accurate orthoimages digital terrain models and 3D models 2 2 Unmanned Aerial Vehicles Unmanned Aerial Vehicles UAVs commonly known as drones are remotely piloted RPA or Unmanned aircraft UA that can be controlled remotely or navigate a pre planned fight path The UAVs are commonly preferred for missions which are too dull dirty or dangerous 3 for a human pilot UAV s have gained increasing attention for use in geosciences due to the possibility of capturing cost effective data at high spatial and temporal resolution 11 This report focuses on small class UAVs which are identified by Australia s Civil Aviation
16. imaging payload was designed that satisfied all design constraints and was successfully integrated onto the CyberQuad A flight planning parameter calculator was created and trial flights were then conducted The planned test methodology to evaluate the gimbal was to collect imagery of a test site flying repeated missions with a given overlap first with gimbal stabilization enabled and then again with the stabilization disabled such that the gimbal remained fixed By contracting licensed surveyors to conduct a conventional surveyof the test site using their data as an absolute reference it was planned that the imagery captured could be processed using photogrammetric software and any improvements due to stabilization be quantified Unfortunately the data from the ground control survey was not provided in time to be used forprocessing however the gimbal did improve image acquisition Further in partnership with the aforementioned surveying company a commercial test flight wasconducted at Kwinana Bulk Terminal surveying an iron ore stockpile with industry grade models generated as a result Development of the project will continue beyond the submission of this thesis and it is hoped that the survey data can be obtained and used for processing This should definitively prove one of the original hypotheses of the research using a stabilized gimbal allows for more efficient flight plans as a lower level of overlap is required Additionally the d
17. into the images properties Exchangeable image file format Exif data is the ancillary information stored within an image file that contains the properties of the image Such metadata typically stored by digital cameras include camera model the date and time the photo was taken and the camera s parameters such as focal length exposure compensation and shutter speed An example of an Images Exif data is given in Figure 65 below e DSC00295 Properties Property White balance Photometric interpretation Digital zoom EXIF version GPS Latitude 32 59 56 083559978 26068 Longitude 115 48 396349199999 Altitude 96 738 File Mame DSCO0295 IPG Item type JPEG image Folder path M Thesis Mapping Imadg Date created 6 10 2012 6 59 PM Date modified 5 10 2012 8 09 PM Size 6 69 MB Attributes A Offline availability Offine stats Remove Properties and Personal Information Figure 65 Image EXIF data GeoSetter is free software program that runs on Windows designed to display and manipulate metadata such as Exif contained in image files 51 GeoSetter was used to automatically synchronize the GPX flight log generated by the Mikrokopter with each images Exif data by using the time stamps from the respective files This allowed the 48 latitude longitude and the altitude of where the photo was taken to be embedded into the images properties This process is shown graphically in Figure 66 D Synchronize with
18. low altitude can potentially capture data at a higher resolution compared to conventional techniques Furthermore data acquisition in cloudy and drizzly weather conditions is still possible as UAVs typically fly below cloud cover Aerial survey and photography is one of the most hazardous jobs in commercial aviation an Australian Transport Safety Bureau report which catalogued flight accidents from 2002 to 2011 showed that 28 of commercial flight fatalities occurred from aerial survey and photography work 14 Utilizing an unmanned aircraft essentially removes all risk to the pilot operator Table 1 ATSB aviation occurrence statistics report 2002 to 2011 Additionally since UAV s can fly with a high level of autonomy and present an low risk to other aviation and objects on the ground an operator requires far less training and certification than a pilot of conventional aircraft 2 2 2 Limitations of UAVs UAV s are not without their limitations due to their endurance and low flying altitude the area they can survey is not comparable to that possible by manned aviation Additionally their size and payload capacity limits the quality and therefore accuracy of the inertial measurement and GPS sensors used position information The class of camera is usually restricted to a compact consumer grade camera For reference conventional photogrammetry uses metric cameras which are specifically purpose designed Metric cameras have stable a
19. pull up by increasing the elevator s deflection The cause of the crash was traced back to mechanical failure of the elevator servo as shown in Figure 24 Figure 26 shows the aircraft s parameters moments before the crash the aircraft pitching heavily downwards with high negative vertical speed despite sufficient groundspeed and near maximum elevator deflection 2 Mission Planner 1214 mav 10 ah ee Kale Bat 1008v0A Figure 26 Mission Planner flight log analysis 4 Phase Two The CyberQuad 4 1 Cyber Technology Cyber Technology is a West Australian based company established in 2006 whichdesign and manufacture a wide variety of Unmanned Aerial Vehicles When they became aware of this thesis and the predicament of the project it was suggested that a surveying payload should be developed for one of their flagship aircraft the CyberQuad Maxi At this point it was decided to shelve development of the fixed wing platform and solely focus on CyberQuad payload development 4 1 CyberQuad Background The CyberQuad is an electric powered VTOL quadcopter platform that uses an autopilot to control its four rotors for stable flight in both manual and autonomous operation 20 Up to 25 minutes Maximum Payload 800 g Table 2 CyberQuad specifications Figure 27 CyberQuad Maxi with HD video payload 63 The CyberQuad Maxi had existing high definition video Figure 27 and thermal optical payload options though lacke
20. range of platforms including fixed wing and VTOL aircraft as well as ground based rovers For each platform the Ardupilot must be loaded with separatesoftware branches calledArduPlane ArduCopter and ArduRover respectively Importantly the Ardupilot has auxiliary servos outputs which can be used for gimbal stabilization and camera triggering Such features are detailed in subsequent sections While a very capable autopilot in its current form since the Ardupilot is an open source project it is possible for a user to code any additional features required For the purposes of evaluation and to gain familiarity with the device the Ardupilot was integrated into a Multiplex Funjet platform 21 shown in Figure 7 below The platform is delta wing aircraft made from elapor foam and was selected because while it has sufficient payload space for an autopilot it sa simple only two control surfaces and durable platform Beyond the Autopilot XBee modems used for telemetry and a pitot tube based airspeed sensor the Funjet uses conventional hobby grade radio control RC equipment Such equipment included a lithium polymer battery RC receiver servos for control surface actuation and an electronic speed controller to drive the 3 phase brushless DC motor Figure 7 Funjet UAV platform with the Ardupilot integrated Configuration of the autopilot was conducted by using the extensive documentation available on project s wiki based manual 22
21. width of RC Switch 4 pulse symbol P5Low 1900 min width of RC Switch 5 pulse symbol P5High 2000 max width of RC Switch 5 pulse symbol P6Low 100 min width of RC Switch 6 pulse symbol P6High 100 max width of RC Switch 6 pulse VKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK KKK KKKKKKK Constants defining valid pulse range VKKKKKKKKKKKKKKKKKK KKK KK KKK KK KK KKK KKK KKK KKK KKK KK KKK KKK KKK kk kk kk kk kk symbolswitchvalid 4 one less than number of switches decodes in a row required for valid switch symbolpulseshort 500 symbolpulselong 3000 VKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK KKK KKKKKKK x Main Program VKKKKKKKKKKKEKKKKKKKKKKK KKK KKK KK KKK KKK KK KKK KKK KK KKK KKK K KK kk kk kk kk kk main lastusb 0 Switchcount 0 times 5 gosub delay wait 0 5 seconds loopl pulsewidth 0 pulsin C 2 1 pulsewidth read RC pulse pulsewidth pulsewidth 10 pulsin times in units of 10us ifpulsewidth 0 then timeout has been reached lastusb 0 times 20 gosub delay wait a while for another go 2 secs goto loopl endif ifpulsewidth gt pulselong then check for pulse too long lastusb 0 goto loopl endif ifpulsewidth lt pulseshort then check for pulse too short lastusb 0 goto loopl endif gosubConvertRC returns with switchnow set ifswitchnow switchlast then if two su
22. 1 C22 2011 12 H EISENBEIB UAV Photogrammetry University of Technology Dresden 2009 13 Y Han AN AUTONOMOUS UNMANNED AERIAL VEHICLE BASED IMAGERY SYSTEM DEVELOPMENT AN REMOTE SENSING IMAGES UTAH STATE UNIVERSITY Logan Utah 2009 14 Australian Transport Safety Bureau Aviation Occurrence Statistics 2002 to 2011 2012 15 SenseFly UAV DroneMapper and SenseFly Imagery Sample 3 2012 Online Available http dronemapper com sensefly3 16 ISPRS The XXII Congress of the International Society for Photogrammetry amp Remote Sensing Online Available http www isprs2012 org Accessed 9 2012 17 senseFly FAQ swinglet CAM Online Available http www sensefly com learning faq Accessed Ji 2012 18 Gatewing X100 Specifications Online Available http www gatewing com specifications 19 K Bosak Secrets of Photomapping 20 DIY Drones store ArduPilot Mega 2 0 3D Robotics 2012 Online Available https store diydrones com APM_2 0 Kit_p br ardupilotmega 03 htm Accessed July 2012 21 Multiplex FunJET Online Available http www multiplexusa com other products model kits funjet html 22 Various ArduPlane manual Online Available http code google com p ardupilot mega wiki home tm 6 Accessed August 2012 23 Hangar 18 Foamaroo Online Available http hangar18uav com foamaroo html Accessed 2012 60 August 24 sphoto DSLR SENSO
23. 2 As shown in Figure 42 motion studies were conducted to ensure there was no fowling or FOV collision when actuating the gimbal about its entire range of movement EP SolidWorks fj Fe Edt view insert Tools Window Hep 3 O B8 H 23 9 Ri 8 E CQ Maxi Wide Assembly V16 y SolidWorks Search s M E 2 NG gt el X N gt ES D A Mirror Entities ka Make Block Add Remove oe A Smart Trim Convert 2 222 Display Delete Quick a Insert 8 Create po O A O X A Entities Entities Offset 222 Linear Sketch Pattern Rel SES Repair Snaps Edit Block Save Block Make Components Mate Move Show layout D Entities Sketch e Part from Component Hidden 7 S da Move Entities DEI Insert Block X Explode Block Block Components Assembly Layout Sketch Evaluate Office Products oO pm cO zx ES O KIEA F j BA CQ Maxi Wide Assembly W16 DSLR NEX 5N Landscapes a 2 Sensors ES Annotations Ze Front Plane KE Top Plane lt Right Plane Origin Q PLANEL GI Ki CQ Maxi Wide Dual Duct V16 lt 1 gt gt Default lt lt Defaults CQ Maxi Wide Dual Duct V16 lt 2 gt gt Default lt lt Default 3 f CQ Maxi Roll Stab Fuselage V16 lt 1 gt gt x Default lt lt De D B Futaba S9070SB Assembly lt 1 gt Default lt lt Default gt _Ap Maxi Roll Stab Baseplate V16 lt 1 gt gt Default lt lt Default gt H PJ710 Bracket V16 lt 1 gt gt x Default lt lt Default gt _Displa S
24. 63 45 la lau la us rs 15 A Camera Orientation focal length mm pixel height pixel width scale focal length height 1 14 spacing across flightline sidelap photo spacing m 6 flightline spacing m Figure 63 Spreadsheet calculations 46 5 2 Data Processing To generate orthomosaics and digital elevation models DEMs from raw images a variety of open source free and commercial photogrammetric software packages were researched and used The desired application of the data being generated dictates how the raw imagery is processed and what software is used to generate the data Imagery can be processed into low accuracy models suitable for visualization or survey grade high resolution georeferenced data This section covers the software used to process the imagery 5 2 1 Basic Model Generation 5 2 1 1 Hypr3D Hypr3D is a free online cloud based service that uses advanced computer vision and digital photogrammetry tools to take 2D photos and turn them into a 3D model 50 Images are uploaded to the service and automatically processed by remote servers generating a model viewable within a browser and downloadable in a variety of industry standard formats Processing typically takes anywhere from 30 minutes to several hours depending on the complexity of the model being generated and the load of the servers at the time Hypr3Dis very simple to use and being a
25. D Motor Run Fly Vario trim up AR Hold Werts 7 0 05 4 2 a s 0x82 24 23 9 Position Hold GPS OK 128 0 0 0 0 Motor Run Fly Vario trim up At Hold Ox82 18 23 10 Position Hold GPS OK 69 128 0 0 0 Motor Run Fly Vario trim up AR Hold 042 26 24 22 Position Mold GPS OK 120 0 0 0 Motor Run Fiy Vario trim up AR Mold 7 D 10 min avg max 0x2 25 25 20 Position Hold GPS OF 99 128 0 0 0 Motor Run Fly Vario trim up Ak Hold min 14 5 max 16 2 Y 0 82 20 24 20 Postion Hold GPS OK 89 128 0 0 0 0 Motor Run Fly Vario trim up AR Hold 6 4 19 48 94 95 306 732 644 ahh 8888 8 Ox82 18 24 12 Postion Mold GPS OK 69 128 0 0 0 Motor Run Fly Vario trim up AR Mold emp 16 42 d Player Trackpoint 82 a 36 2 2 0 5 e em 2 H epp 34 y MM 1 da maa 044 ll E E 20 pos D 4 e EE y y Speed 1 0 sec DIE A Loop Error CG FC Flag Emergency Landing 4 occured 2 times GraphViow 2 Tohia 16 20 ee et Syexend 5 01 58 08 35 Figure 54 MKGPXTool 47 4 10 Issues Faced During testing of the reused Navi Control sporadic magnetometer readings were noted Viewing the magnetometer s readings in MK Tool Figure 55 they would jump from expected values lt 100 to near zero 40 gt MikroKopter Tool V1 78d c www mikrokopter de Analog click to switch scope MikroRopter 16 START Settings SE 17 18 14 heat mt gt FlightCrl
26. H Figure 33 Gimbal with CCD camera 4 4 Camera Triggering Interface Using a servo to mechanically actuate the shutter button Figure 34 is a simple technique that has been used successfully by many hobbyists however it was not deemed to be adequate for a production grade payload 27 Figure 34 NEX 7 with mechanical servo trigger 76 One alternate method is electronically triggering the cameras stutter by directly soldering a transistor or MOSFET parallel to the shutter button Figure 35 This solution is used in the Swinglet s camera payload Figure 36 but it requires disassembling the camera which is a delicate operation and Increases production time Figure 35 NEX 5Nmodified for electrical triggering 77 28 sano Figure 36 The Swinglet CAM s camera integration Fortunately the NEX 5N features an infrared remote port on the front of the camera An open source project had developed an infrared trigger using an Arduino microcontroller 39 and it would have been possible to adapt the code of the aforementioned S95 camera trigger to make it compatible but due to time constraints a commercial solution was sort Research uncovered a company called Gentles Ltd that specializes in a range of devices for triggering the shutter and or zoom of cameras and camcorders 40 fortunately they had a product called the gentLED SHUTTER Figure 37 that is compatible with the NEX 5N gentLED SHUTTER is a solution to trigger digi
27. MI cable The NEX 5N has an accessory port on top of the camera that allows an external flash or electronic viewfinder Figure 32 to be connected Retracted due to copyright Figure 32 Sony OLED Electronic Viewfinder for NEX 5N Camera 37 26 It was hoped that one of the exposed pins on the accessory port may carry a composite video signal however after some research it was found that the camera communicates with the LCD module transmit via a proprietary LCD signal bus It should be noted that LCDs require the following basic timing signals 38 e VSYNC Vertical Sync for TFT or FP Frame Pulse for STN o Used to reset the LCD row pointer to top of the display e HSYNC Horizontal sync for TFT or LP Line Pulse for STN o Used to reset the LCD column pointer to the edge of the display e DO dXX 1 or more data lines o Data line function varies in STN and TFT modes and panel type e LCDCLK LCD clock o Used to panel control refresh rate As such it was determined that the only method of getting video output from the camera was indeed the mini HDMI port With time running out and the custom HDMI cable not working a Mini CCD analogue video camera was attached to the front of the gimbal as shown in Figure 33 While this allows for payload aiming it doesn t give any information about the camera such as its battery level memory capacity remaining or if the camera is indeed triggering photos F wei fy N hd gt FN sw Te Kg SE
28. PX Datas Default 1000 The logging period should not be set to below 500ms otherwise the performance of the Navi Crtl can be affected 32 Standard Navi Ctrl boards have a 250m waypoint range limit meaning that waypoints that are beyond a 250m radius from the operator cannot be navigated to however position hold and return to home functionality work as expected if the craft is manually flown beyond this distance 250m was deemed to be too limiting so a commercial licence was purchased which extended the navigation range to 500m This allows the CyberQuad to fly up to 3 14km though for this surveysize the aircrafts endurance would become a limiting factor 4 1 3 Powertrain The CyberQuaduses a 4 cell lithium polymer battery to power the avionics and the aircrafts four rotors Each rotor powertrain consists of an optimized propeller a custom wound three phase brushless dc motor and an electronic speed controller called the BL Ctrl which 22 is capable of providing 35A to the motor and communicates with the flight control board via I C bus 4 1 4 Ground control station Like the Ardupilot the CyberQuad can connect to a ground control station via an XBee telemetry link allowing for remote configuration telemetry data and waypoint navigation Control The Windows based software used by the autopilot is called MikroKopter tool or MK Tool 33 Relevant usage of MK Tool is described in subsequent sections 4 2 Revi
29. R SIZE AND PIXEL DENSITY Online Available http www sphoto com techinfo dsirsensors dsirsensors htm Accessed 2012 25 Various CHDK Manual Online Available http chdk wikia com wiki CHDK 26 B Daum The Canon Camera Hackers Manual Santa Barbara rockynook 2010 27 Revolution Education Ltd PICAXE Manual 2012 28 srnet RC Remote Control Interface RCgroups 2011 29 Sparkfun HTC ExtUSB 11 Pin USB Connector with Breakout Online Available https www sparkfun com products 9167 30 Modelflight Seagull Models Boomerang 40 Online Available http www modelflight com au products Seagull Models Boomerang A0 RC Trainer_Plane_ARF 4454 10 html Accessed August 2012 31 D Foster GPX the GPS Exchange Format Online Available http www topografix com gpx asp Accessed 2013 11 32 MikroKopter NaviCtrl Online Available http www mikrokopter de ucwiki en NaviCtrl_2 0 Accessed October 2012 33 MikroKopter MikroKopterTool Online Available http mikrokopter de ucwiki MikroKopterTool Accessed September 2012 34 Teradek Teradek Cube Online Available http www teradek com pages cube Accessed Octobe 2012 35 Lockheed Martin Digital IP Video Data Link Online Available http www lockheedmartin com us products procerus digital ip video data link html Accessed October 2012 36 J Bandlow HDMI Is Here 1 May 2007 Online Av
30. SING UNMANNED AERIAL VEHICLE APPROACH in Internatio Archives of the Photogrammetry Remote Sensing and Spatial Information Sciences Volume XXXIX B7 Melbourne 2012 67 A L C W D T Luke Wallace Development of a UAV LiDAR System with Application to Forest Inventory Remote Sensing vol 4 pp 1519 1543 2012 62 68 PERFORMANCE TEST ON UAV BASED PHOTOGRAMMETRIC DATA COLLECTION in International Archi of the Photogrammetry Remote Sensing and Spatial Information Sciences Volume XXXVIII 1 C22 Zuric 2011 69 DPCAV 900MHZ A V TRANSMITTER INTERFERENCE 15 February 2009 Online Available www dpcav com data_sheets whitepaper_RFl pdf Accessed July 2012 70 TrueRC Analog video December 2011 Online Available http www truerc net images tutorials Analogvideo pdf Accessed September 2012 71 AgiSoft LLC Agisoft PhotoScan User Manual St Petersburg 2012 72 H Millward Some Key Terms in Aerial Photography 73 P Kuiper OrthoPerspective JPG 74 M Over DTM DSM png 21 January 2011 Online Available http en wikipedia org wiki File DTM_DSM png Accessed September 2012 75 Moxfyre Sensor sizes diagram 2009 76 Juergen Wireless remote control and panorama setup for Sony NEX 7 Online Available http www panotwins de technical wireless remote control for sony nex 7 Accessed August 2012 77 PhotoShip One Sony NEX5N Trigger Modification 25 October 2011 O
31. Table 5 HDMI Pinout
32. Width mm y y 116 5 109 G Body Height mm 62 5 66 WEI Body Depth mm 7 36 6 32 J 11 Remote Control N A Unknown i GPS Tagging External External External External Composite Video Out No No Yes needs testing No HDMI Output Yes Yes Pancake Lens FOV 83 63 30 Price with Lens AUD 85 799 Battery life CIPA rating sl 430 460 230 Eye Fi Campatability Y Ze Y een Click to add footer lq 4 gt Dl HD Video Cameras DSLR Cameras Compact Still Cameras IP Video Video Recorders Laser Rangefinders EJ DEI Ready Page 1of2 Figure 82 Camera evaluation spreadsheet 65 C Programming the PICAXE microcontroller The computer used for PICAXE code development computer did not have a serial RS 232 port A FTDI 59 based USB to TTL serial converter board was available Transistor transistor logic TTL logic voltage levels do not exceed 5V The RS 232 standard uses inverse logic one is defined as a negative voltage where signals are 3 to 15 volts for lowor 3 to 15 volts for high for data transmission lines TxD RxD and their secondary channel equivalents 60 The PICAXE specifications stated inputs should be 0 8 x power supply voltage to be high below 0 2 x power supply voltage to be low 27 It was possible to configure the FTDI chip with the FT Prog utility to invert the data transmission signals Figure 83 and once this was done it was possible to use the FTDI converter board both to power progr
33. able detects the pulse the servo toggle time left at the default value of 200ms This is shown in Figure 50 below setup of Outl Oute J16 amp J17 FEWY1x SV 2 1 amp SV2 5 FC V2 x Click to change sequence Out Bitmask SS Outil Timing E in Only active after motor start Wu Figure 50 Trigger switch configuration 4 9 Autopilot tuning The CyberQuad s autopilot has already been tuned for existing payloads such as the HD video however in such payloads smooth and damped responses were desired For use in aerial survey as only still images are taken a more aggressive response is possible without reducing the quality of the images captured Additionally to increase the aircraft s flight envelope wind resistance maximum flight soeeds and bank angles were tweaked Fundamentally the Mikrokopter s autopilot uses a nested control structure with outer loop navigation controllers calculating the set points for inner loop roll pitch and yaw attitude controllers Figure 51 shows a sub section of the control structure of another autopilot the Arducopter which is also designed to fly a multi rotor aircraft Roll Axis Rate deg 100 s Desired Rate deg 100 s angle in deg 100 Rate Error deg 100 s Servo _out deg 100 s A Error target_angle deg 100 A mix of command and nav control ES Le RATE_ROLL_P RAITE ROLL STABILIZE_ROLL_P STABILIZE_ROLL_
34. adius around each Waypoint 0 Grid Rotation A A Waypoint 10 24 Radius m Heading Direction in which the Kopter points after reaching the Waypoint Dependent on 80 24 Altitude m site 0 24 Heading Cam Nick Tilt of the camera while reaching the Waypoint fo 24 Cam Nick 1 Speed 0 1m s Speed in which the Waypoints are flown 30 Speed 0 1m s 30 8 Climb rate 0 1m s Speed in which the Kopter climbs falls between the Waypoints H Hl DelayTime s 0 1m s mmm Delay Time s Waiting period per Waypoint If you enter a 0 here the Kopter will not stop F WP Prefi at that Waypoint instead the Kopter flies to the next one rella E V Delete existing WPs Trigger Time Generate Delete existing When creating new Waypoints the previous ones will be deleted WPs Figure 58 Waypoint Generator 49 Once a flight path has been generated it is uploaded to the aircraft by clicking on the red arrow with the text Send waypoints to Navi Ctrl Figure 59 New waypoints can be uploaded while the aircraft is inflight gd Imagesize 774x393 Position 1 000000 0 036176 File Data Link WayPoints Display GPS coordinates no OSD data Altitude 4 Data Link ERR Mode Speed mfs Thrust Time LZ ff Send waypoints to NaviCtrl Figure 59 MK Tool upload waypoints One limitation of the autopilot is that it can only store 32 waypoints at any one time meaning that for larger areas t
35. advantaged and limitations of UAVs compared to full scale aviation and other conventional aerial surveying techniques The book also covers UAS operation procedure flight planning including recommended camera settings Such as exposure time and mission configuration such as photo overlap airspeeds and altitudes and their respective relationships with pixel resolution cm pixel and flight coverage The data provided is backed up with theory and substantial empirical test data THE DEVELOPMENT OF A DIRECT GEOREFERENCING READY UAV BASED PHOTOGRAMMETRY PLATFORM 56 64 The researches integrated a high quality Global Positioning System GPS Inertial Navigation System INS and data logger into aircraft s payload This removed the necessity for GCPs and allowed for direct georeferencing of the captured images This increases operational flexibility and efficiency While such a luxury can be afforded to an aerial platform of the size used it is unlikely that this could be achieved for the platforms being used in this thesis Elements of Photogrammetry 57 and Elementary Air Survey 58 are books that predate the avent of digital cameras and the development of modern UAVs They do however give a good insight into convertional photogrammetric techniques and principles Of particular use were fundamental aerial photography formulas and flight planning ground control and aerotriangulation techniques In addition to the aforementioned Photogramme
36. agery A Ka Figure 72Google Maps Imagery 53 H EEN Ab n C Ye Ferns d Figure 74 CyberQuad Imagery Additionally the benefits of stabilization become apparent when comparing gimbal Stabilized flight imagery Figure 75 to that from non stabilized flights Figure 76 ae Figure 75 Stabilized flight Image Figure 76 Non stabilized flight Image 54 A selection of the imagery was processed using Hypr3D allowing for low resolution 3D models to be generated Figure 77 Pa Field Test v3 Submitted by Nick Sargeant October 05 2012 85 views S DESCRIPTION INFORMATION DOWNLOADS Login to download these mode files New Hypr Factor 100 0 Registration is fast and free High Resolution Model DAE amp JPG High Resolution Point Cloud PLY Figure 77Hypr3D model of site images Uploaded The one flight s imagery was fully processed with Pix4D and an orthomosaic and digital elevation model generated The DEM has sufficient resolution to distinguish tire marks in the sand Figure 78 below shows the DEM and an elevation profile along the site Jee Legend Let C Legend Center 2 A Legend Right C Elevation Visibilty Target Height meters Elevation EF Observer s Hecht meters Figure 78 Generated DEM with elevation profile Because GCP data was not used in the processing it is not possible to determine the absolute accuracy of the mod
37. ailable http www cable360 net ct operations bestpractices Accessed October 2012 37 Sony Electronic Viewfinder 2012 Online Available http store sony com p Sony Alpha NEX 5N Digital SLR Camera Wide Angle Viewfinder View Finder en p FDAEV1S Accessed September 2012 38 NXP Philips Introduction to graphics and LCD 39 M Lane Arduino Timelapse IR remote for NEX 5 Online Available http www l8ter com p 333 40 Gentles Limited gentLED SHUTTER S gentLED ZOOM Online Available http www gentles Itd uk gentled shutter z00m htm Accessed August 2012 41 Gentles Limited Gentled IR SHUTTER Manual November 2005 Online Available www gentles Itd uk gentled 42 Solidworks Motion Study Elements Overview Online Available http help solidworks com 2012 English solidworks motionstudies simulation_elements_overview h Accessed 2012 43 MikroKopter MiktoKopter Wiki Manual Online Available http www mikrokopter de ucwiki StartSeite Accessed 2012 September 44 ServoCity Futaba Servo Splines Online Available http www servocity com html futaba_servo_splines html 45 J Short ArduCopter roll axis stabilization control loop Online Available http wiki ardupilot mega googlecode com git images PIPI_Flow png Accessed October 2012 61 46 I S a P Corke Estimation and Control for an Open Source Quadcopter IEEE 2011 47 MikroKopter
38. al integration between the ducts Mu 25 Figure 30 Camera gimbal fit Male HDMI and Mini HDMI plugs with a breakout printed circuit board PCB were sourced and the HDMI specification reviewed to see if a low profile cable could be hand soldered HDMI uses a signalling method called transition minimized differential signalling TMDS This is a flavour of low voltage differential signalling LVDS An LVDS signal is 300 mv peak to peak into a 100 ohm twisted pair similar to the twisted pair seen inside an Ethernet cable the difference being that the HDMI cable uses a separate shield around each video pair to minimize crosstalk 36 The pinout for the HDMI plug can be found in Appendix F As the soldered cable only needed to be a short distance lt 10cm research indicated that it should be possible to hand solder and omit shielding on each twisted pair Due to the small pitch of the connector 26AWG insulated wire was used Unfortunately after delicately soldering a Mini HDMI to HDMladapter cable and taking care to equally match wire lengths the cable was bench tested and didn t work After double checking the soldering and testing each wire s proved unsuccessful the custom HDMI cable was abandoned due to time constraints It is suspected the cause of the fault is due to the lack of shielding Figure 31 shows cable when only half completed Danad y ws mm m kw _ Figure 31 Custom HD
39. am the PICAXE based prototype circuit rt FT Prog Device 0 Loc 1D 0x116 a EEPROM File Devices Help a E dl PFI G Device 0 Loc 10 0x116 E p FT EEPROM gt Chip Details Osch USB Device Descriptor cb USB Config Descriptor gt USB String Descriptors Hardware Specific gt HighlO 2 ExternalOscillator p Invert RS232 Signals gt 10 Controls Figure 83 Configuring FTDI chip Invert TAD Invert RXD Invert RTSH Invert CTS Invert DTR Invert DSR Invert DCD Invert RIA Information Box Invert RS232 Signals This device allows the user to invert the RS232 signals Read EEPROM Device 0 Nord z 0040 A220 z 4900 2 2000 5400 4600 2 0000 2 0000 2 2704 2 0000 0304 C212 2003 5500 1203 4500 0000 0000 DEFE 0000 0160 310 4600 5300 4100 ooo ooo ooo ooga aoga a a Bl OR AAR ooge 0500 5400 4200 3600 ooga o000 o000 58D aga goag 5400 3200 4100 5200 gogg ogag 000 ooo 4744 66 D PICAXE Program RC Camera Interface Cable Author Nick Sargeant adapted from code provided by Stuart Robinson See http www rcgroups com forums showthread php t 1387379 for original UK UK x Date 09 2012 x Version 0 1 for PICAXE 08M2 Uses default of 4Mhz internal clock rx Notes This program reads a RC pulse of nominal ims to 2ms and converts it to USB Power pulses for CHDK camera interface ss Mix pylse
40. an additional platform was sought to continue the project s progress The only suitable aircraft that was immediately available was a Boomerang 40 shown in Figure 23 which was loaned from a colleague The Boomerang 40 is a standard high wing trainer type aircraft constructed from film coated balsa 30 P ES A _ 2 E Figure 23 Boomerang 40 aircraft 83 The ArduPilot Mega 2 0 autopilot and the roll stabilized camera gimbal were integrated into the airframe The autopilot was appropriately configured and following pre flight checks and a manual flight the platform was successfully flown autonomously Unfortunately during a subsequent test flight an In flight failure led to a catastrophic crash destroying the airframe propulsion system flight battery camera gimbal and damaging avionics The wreckage is shown in Figure 25 Figure 24 Failed elevator servo Figure 25 Crash aftermath 19 The autopilot acts like a black box and automatically logs many parameters most importantly the aircraft s attitude and position flight mode manual assisted autonomous operator inputs and the autopilot s control outputs Fortunately these logs were able to be extracted from the damaged autopilot and it was shown that the autopilot was giving the correct control outputs and flying the aircraft above its stall soeed leading up to the crash The aircraft entered a dive and continued to do so despite the autopilot attempting to
41. as designed and constructed During its development delays in delivery of procured items and a serious crash of the UAV compromised the ability of the project to be completed Partnering with Cyber Technology and having the opportunity to develop and integrate a surveying payload for the CyberQuad presented a great opportunity and presented many challenges 58 Some of the the major milestones of this project identified in project proposal were Completing initial literature review Selection of components and payload design Payload construction Successful payload Integration into a UAV Data processing and generationof orthomosaics and digital elevation models DEMs All of these objectives were completed to a high standard and survey grade data was produced using the payload developed A trial was conducted at iron ore stockpile and accurate models were generated that were otherwise quoted to cost 6000 had traditional aerial surveying be used Using a stabilized gimbal was shown to improve image acquisition and therefore allowing for less flight overlap however without the GCP data this was unable to be quantified Cyber Technology was satisfied with the payload developed and following minor revisions it will subsequently be sold as a new payload option for the CyberQuad 59 9 References 1 Pegasus UAV Mapping Online Available http www pegasus4europe com node 15 2 Cyber Technology About Cyber Technology Onli
42. ata generated from processing should allow an estimated function of overlap vs model accuracy to be determined allowing future flight plans to be optimized Contents ge e E i Me Eo le V ll EC ee vi Il ADDreviations ana BE nee KE viii IVs Acknowlede MEN ia as xii T Thesis Structure iii oie 1 De o e e Pro yaerdei ect aeorea ate ce ecto rn needa eee 1 Z Nic Le gel e lee aa alud 1 2 2 Unmanned REENEN 1 Z 2A ROVANTACCS CP UAVS oda 2 222 EE eegen 3 2 POE COD ECL VOS Ee 3 2A Literature e e al 4 20 EXISTING SOIUTOD S anar araar bo 4 2 6 Camera Fundamentals ia 6 236 1 Camera etnias 6 26 2 Camera MOE Saa dada last 6 S Phase One Initial Development ere 7 SL AUTOPILOT CVal Ut OM irte 7 SE EE ET 8 3 2 Camera electo eri a a ide 9 3 52 CHDIK Custom Camera FiemMmWa iia iio 11 3 4 Autopilot Camera trigger interface Cable ooccccocccncnncnnncnanononacononaronconacononarononarononos 12 3 5 ROllestabilized RE ul CT E 16 3 06 Autopilot GimbalContiguration tanda dd 18 DT ge ek ge dado 19 A Phase TWO The EVDer OU liada 20 A A aeeesenanscseaac ota R 20 AA ee el E 20 ASES AMAN A E 21 AZ AVIONI S nna N cat ase EN aries dane yd eee ee 21 ALO ee d E E 22 ALA Ground CONUCO Ee ss 23 4 2 Revised Camera Selecon nn nrnnnnrnonronnanacnnnnono 23 AAC Ree E A od 24 LA ECHTEN E gea ri 27 IS SiMbal Desi aii a 29 4 6 Autopilot Gimbal Camera trigger Connection 33 47 AUtopilotGimbal Cont Urat Ni 33 4 8 Camera T
43. atabase iaa A ae 45 FeureG3 EE 46 Figure 64 HypraD MONO lui ais 47 BA mage EXE taria 48 Figure 66 Image synchronisation with GeoSetter cccccessccccssececesececeesceceeseceeeeceseueceesenees 49 FIGURE 67 Geosetter GU di 50 Re PIDO Coud CU E 51 Fig re 69 PIX4D PrOCeSSING eg e 51 Figure 70 Example flieht path at the test sterii A ENAA 52 Ieren ee SE Figure 7260026 Maps ET EE 53 Figure SNearmap Mater sitiada 53 EIER 54 Figure 75 Stabilized fient Innate senis a a a 54 Fig re 76 e ele TIBMU on TE 54 FigUre7 7 AV OFS MOGEl Or Stein 55 Figure 78 Generated DEM with elevation profile 55 Figure a as e WEE 56 BEA OO ere Ban El ri 57 Figure 81 PhotoScan processing Of the Sit sisisi eiiiai A EE a E 57 Figure S2 Camera CVdlUation spreadsheet ee 65 Fig re 83 Contie rine FI DI CO Pan io 66 SIT Te Wiele EE 71 II List of tables Table 1 ATSB aviation occurrence statistics report 2002 to 20 3 Table 2 EvberQuad Ke Tel eg e iria cairo 21 Table 3 Camera specitcacOnS iaa 24 Table 4 Trigger configuration SUMMA Miss EE 37 Fable SVP WO ess aces tat gee ed a id 71 vil IL Abbreviations and Definitions As this is an Engineering report many readers may be unfamiliar with some of the surveying and aerial photography terminology used As such it was deemed appropriate to include background information and definitions of some key principles in addition to abbreviations 2D Two Dimensional 3D Three Dimensional AGL Above ground l
44. ccessive same switch decodes then inc by 1 switchcount switchcount 1 elseswitchcount 0 endif record the current switch decode switchlast switchnow ifswitchnow 0 then do nothing if switchnow 0 switchcount 0 goto loopl endif ifswitchcount lt switchvalid then check if enough pulses recvd in sequence goto loopl endif ifswitchnow lt gt lastusb then if the switch number is different send the new USB powerpulse iflastusb gt 0 then gosubsendUSB endif lastusb switchnow save the number of this USB power pulse being sent endif if here valid decode USB sent so zero and back to start switchnow 0 switchlast 0 switchcount 0 goto loopl read another pulse ifpulsewidth gt P6low AND pulsewidth lt P high then switchnow 6 endif return 68 VAXKAXKKKKKKXXKXXXXXKKKKKKXXXXKKKKKKKKK AAA KK AAA AAA AAA RAR x General Routines t kkk kk Rk k k kkk Rk kK Rk kk KKK KK KKK KKK KKK KKK KKK KKK KKK KKK KK AAA AAA AAA Ek kk Ek AAA AAA RA general purpose 100ms delay delay do while times gt 0 pause 100 times times 1 loop return this sends the USB pulse to the Camera sendusB SERTXD switchnow Degug USB output pulse times switchnow high c 1 Start the USB power pulse gosub delay number of 100ms delays is in times low cl Stop the USB power pulse return this converts the pulswidth into a switch value convertRC SERTXD pulsewidth Degu
45. ch University Dr Gareth Lee Lecturer Associate Professor Graeme R Cole Lecturer Professor Parisa A Bahri Head of School Cyber Technology Joshua Portlock CyberQuad Project Manager Paul Dewar General Manager Chris Mounkley Managing Director Thanks are also due to friends and family for their support and encouragement thought the duration of the project To any undergraduates reading this report every word written is a step closer to finishing xii 1 Thesis Structure Following a comprehensive introduction that covers background information a literature review and an evaluation of existing solutions the project s scope and objectives are identified Following this the report is split into distinct Phases that cover each stage of the project Phase One covers development of a fixed wing UAV platform and an appropriate payload system for aerial surveying Phase Two shifts the project s focus to design a surveying payload for an existing commercial UAV system called the CyberQuad Phase Three details the workflow of an aerial surveying mission including flight planning data acquisition and data processing using a range of photogrammetric software Phase Fourcovers test flights that were conducted including a case study of commercial trial survey of an Iron ore stockpile The solution is evaluated and a summary of the project is made 2 Introduction ENG460 is the engineering thesis unit under the school of Engineering
46. d a purpose built payload for aerial photography and surveying and such a capability was required One of the limitations of the CyberQuad was an estimated endurance of approximately 10 15 minutes when carrying an appropriate surveying payload As such using a stabilized gimbal that allows the overlap of a surveying flight to be reduced is very advantageous For the purpose of this project a CyberQuad Maxi platform was assembled from refurbished components and earlier generation obsolete hardware All components were tested before being used 4 1 1 Airframe The CyberQuad s airframe is manufactured using Selective laser sintering SLS SLS is a rapid prototyping low volume manufacturing technique that uses a laser to melt and fuse small particle of different materials in this case nylon 3D printing doesn t have the huge upfront tooling costs associated with Injection moulding and can offer more design flexibility than if an item was to be milled from a solid billet For example a completely hollow component or one with compound curves something that would be very difficult if not impossible to manufacture using conventions techniques is no more complex to manufacture Once an object is printed few finishing processes are required before the component can be used Compared to other 3D printing additive manufacturing methods SLS has the best combination of strength weight ductility and material finish 4 1 2 Avionics The C
47. d not fall within field of view of the camera e Access to the battery SD card HDMI port for video out must not obstructed by the gimbal e The camera s screen must not obscured A cardboard prototype shown in Figure 39 below was constructed to understand the gimbals basic structure and to help visualize and possible locations of the servo and how they would actuate the gimbal Figure 39 Cardboard prototype 30 Following the cardboard prototype a prototype design was drawn in Solidworks An accurate both dimensionally and in terms of mass distribution model of the NEX 5N camera was also drawn to assist in the design Existing CyberQuad components including the fuselage ducts and base plate had already been drawn and Solidworks allowed for components to be integrated into an assembly to see how they fit together Figure 40 shows the modelled size constraint on the gimbal to ensure it wouldn t fowl on the aircraft s ducts SolidWorks 8 Fe Edt view insert Toos window Help 9 da a ee ee E CQ Maxi Wide Assembly V16 SolidWorks Search AA gt G Mirror Entities Dista vDelet d e O Bhe hos SR offset ace near Sketch Pattern eil vg z Repar DER Edit Glock sl Save Glock Make gt ve Mate Me E layout Mes D s a A e mie 7 DS Gesten Component Hidden CH 4 sg Move Entities Insert Glock Let Explode Glock Back Components Assembly Layout Sketch evaluate Once Products QAERS d s R O
48. djusted in the Settings window of MK Tools Figure 53 Parameterset 3 Easy Channels Configuration Stick DER Looping Altitude Camera Navi Ctrl Navi Ctrl 2 Output Misc Gyro User Coupling Mixer SETUP Easy Setup Gyro P Gyro I Gyro D Dynamic stability ACC Gyro Faktor ACC Gyro Comp Main l DriftCompensation Gyro stability Motor smooth Bir BPs 9 1 Parameterset yo ER 100 120 100 Yaw P 120 Yaw I 10 DE D 1 0 P h Rotationrate limiter v e CH 39 Figure 53 MikroKopter tuning parameters MKGPXTool Figure 54 is an additional open source program that allows visualization and post flight offline analysis of the gpx log files which are generated by the Navi Control and stored on the Micro SD card MKGPXTool was used to assist in tuning the autopilot and diagnosing any unexpected flight behaviour MK GPX Tool O 2 0 0beta 0 88m DIN 2 GridView 4G i SZ Kl y g dilemaorPoner FC GC EsrorCoanter Ansiogirgouts Nisg Text 5 tort mm Version FC H 2 1 SV 0 88e NC HW 2 0 SW 0 26i D 4 11 Postion Hold s pelo trim up Verlo trim down Alt Hold 00 000 0x82 25 24 12 Postion Hold GPS OK Plight time 17 16 10 17 25 80 460 secs 00 07 40 Total 4 secs 00 07 51 SS 5 082 18 24 20 Postion Mold GPS OK 3 128 0 0 0 Motor Run Fly Vario trim up AR Hold pedo ora nee e 5 000 0x82 3 23 18 Postion Hoki GPS OF 91 128 0 D
49. durance of 45 minutes Figure 8 The Foamaroo platform 23 3 2 Camera Selection At the same time aerial platforms were being researched different digital single lens reflex DSLR Mirrorless interchangeable lens camera MILC and compact cameras were being researched to gauge their suitability for integration into the payload A spread sheet of different cameras and their relevant specifications was collated See appendix B Important specifications of cameras include e Weight and size o The camera must be small enough to be carried by the airframe Additionally an aircraft s endurance is affected by the weight of the payload e Camera Megapixels o The camera s megapixel count is proportional to thecaptured ground resolution for a given altitude e Sensor size o Most common point and shoot cameras have a 1 2 5 imaging sensor For a given number of megapixels a large sensor size decreases the pixel density which should decrease both the amount of random digital noise present in an image and the images dynamic range 24 Simply and in generic terms a larger camera sensor typically has increasedperformance in low light or high shutter speed situations something advantageous in aerial platform Figure 9 shows a scaled comparison of various standard sensor sizes Medium format Kodak KAF 39000 sensor 35 mm full frame APS H Canon APS C Nikon DX lt Pentax Sony APS C Canon Foveon Sigma Four Third
50. e of the area that was being mapped and if there were any inaccuracies within the aircraft s GPS flight log It should be noted that due to the comparatively low end GPS and IMU sensors used by the autopilot the coordinates recorded are only absolutely accurate with reverence to a ground coordinate system to approximately 5m To make precise and meaningful measurements form aerial photographs it is essential to be able to relate images to actual points on the ground s surface Additionally ground checkpoints are used by photogrammetric software to perform a quantitative assessment of image location error As such a conventional ground control point GCP survey was conducted by licensed surveyors This is detailed in the Testing section of the report 49 GeoSetter Die Images Search l Filter Map View Help t O Es WUsers Sarge Desktop DCIM 110MSDCF D WE A INNAM et 23 10 2012 6 08 0 23 10 2012 6 08 1 S32 12 q 4 532 12 gee 23 10 2012 6 23 10 2012 6 08 4 32 12 Se SC S32 12 Zei 23 1 ind 6 06 2 23 10 2012 6 06 4 32 12 os 4 532 12 ae 4 we rari Go Geo OSCO0415 416 DSC00417 DSC00418 DSC00419 DSC00420 Sr tetra Aaa rene der dr teo 23 10 2012 6 09 1 23 10 2012 6 09 2 23 10 2012 6 08 5 32 12 SEH Ph 53212 Ea 23 10 2012 6 09 4 EDS 09 5 23 10 2012 6 10 1 1 23 10 2012 6 10 2 532 12 Geen S32
51. e for aerial photography as motion blur occurs when the camera is moved during exposure A fast shutter speed also reduces the amount of light hitting the image sensor making the image darker e The ISO rating which typically ranges in value from 25 to 3200 indicates the indexed light sensitivity of the sensor A higher ISO more sensitive allows for shooting in lower light conditions but comes as the consequence of increasing the amount of digital noise inherent in the photo As all settings are coupled it is impossible to make an independent change to one of the elements without having to adjust another to maintain a constant exposure value 2 6 2 Camera Modes Cameras can be set to take a picture using a variety of shooting modes that increase the automatic decision making of the camera Beyond fully automatic where the camera dynamically calculates appropriate element values each time the shutter is pressed there are semi automatic modes which give the photographer more control These modes include e Shutter Priority Tv where the operator sets the shutter speed and the camera determines the aperture given an ISO sensitivity e Aperture Priority Av where the operator selects the aperture and the camera calculates a shutter speed given an ISO sensitivity For aerial photography where many images are taken it is important that all images have a constant exposure This is achieved by operating the camera in Manual mode w
52. el of overlap is required will be tested The planned test methodology to evaluate the gimbal was to collect imagery of a test site flying repeated missions with a given overlap first with gimbal stabilization enabled and then again with the stabilization disabled such that the gimbal remained fixed By contracting licensed surveyors to conduct a conventional survey of the test site using their data as an absolute reference it will be possible that the imagery captured could be processed using photogrammetric software and any improvements due to stabilization be quantified 2 4 Literature Review Over 20 Papers relating to the use of unmanned aerial vehicles were presented at the XXII Congress of the International Society for Photogrammetry Remote Sensing 16 which was held between 25 of August to the 1 of September 2012 There were many papers that aligned perfectly using purely optical payloads on small UAVs Other papers covered more exotic technologies such as multispectral or thermal imaging systems particular mission scenarios such as archaeological survey or for rapid disaster assessment however significant knowledge was gained from all papers A comprehensive literature review is included in AppendixA 2 5 Existing Solutions There are existing commercial UAV solutions designed for photogrammetry use the most prominent being senseFly s swingletCAM 17 and Gatewing s X100 18 While these platforms are functional they
53. els generated however 55 6 2 Case Study Mapping an Iron Ore stockpile A survey company Cyber technology partnered with had a client in the mineral resources industry that had multiple stockpiles of coal and iron ore It was requested that a trial surveying flight be conducted to test the capabilities of the system A conventional aerial survey was quoted to cost 6000 The flight was scheduled for early morning however it was delayed due to a miscommunication over induction duration and wasn t conducted until the mid afternoon by which time the weather conditions had severely deteriorated with winds gusting in excess of 25 knots Despite this it was decided that the mission would proceed with caution The stockpile chosen was approximately 100x400 m and the survey company requested that photos be taken with an80 overlap and wanted a GSD lt 3cm which corresponded to a flying altitude of 100m Using the flight planning spreadsheet to calculate flight parameters a lawnmower waypoint pattern was generated by MK Tools After an initial flight check it was demined that due to the strong sea breeze the aircraft could not autonomously navigate upwind as the angle of bank and maximum throttle is limited in autonomous mode The flight plan was modified so that the aircraft was manually flown unwind and would autonomously navigate back down wind The mission was split into three individual flights flying 400m strips Each flight took approximately 5
54. ement would not have been possible The servo selected was metal geared which are stronger and more durable and had sufficient torque It is important to note that the in this configuration servo based gimbal stabilization is proportional open loop control as there is no way to connect sensors on the gimbal itself to provide attitude feedback Feedback control could be implemented if there was an IMU unit coupled to the gimbal or there were rotary encoders on each degree of freedom The closed loop control is entirely within the actuators themselves Servos use a potentiometer or rotary encoder connected to the output shaft to measure position An amplifier based analogue circuit or a microcontroller in more modern servos then applies power to the motor in proportion to the distance it needs to travel As has been stated a PWM signal is used to command the desired position to the servo Following design the mount was 3d printed with a Makerbot Replicator using ABS plastic filament The Replicator uses fused deposition modelling FDM a processwheremolten plastics areextruded by a nozzle that traces the parts cross sectional geometry layer by layer The printed gimbal is shown in Figure 19 wwen Figure 19 Printed Gimbal 17 3 6 Autopilot Gimbal Configuration To ensure the autopilot correctly stabilized the gimbal parameters such as the correct neutral point travel range and stabilization gain had to be configured on the au
55. era s axisis no longer orthogonal relative to groundwhich ultimately reduces the quality of the data captured Research identified from the literature review showed that payload stabilization increases useful data capture during banking and increases processing success rate thanks to overall more predictable photo properties 7 In addition even when ordered to fly straight over ground deviations in roll and pitch of a few degrees occur due to turbulence and require extra image overlap pre planned Such overlap is costly in terms of flight time and performance worsens significantly during windy weather 7 As such the primary focus of this project was to design an improved imaging payload design that actively stabilized the camera The project started by evaluating a sub 200 open source autopilot called the Ardupilot in a fixed wing aircraft An appropriate camera and airframe were selected and a stabilized gimbal designed During the project setbacks were encountered whenCyber Technology a company that provides UAV solutions for search and rescue operations military support high end surveillance law enforcement environmental conservation agricultural operations oil amp gas structural inspection operations and cinematography photography applications 2 showed interest and suggested that the project should instead focus on designing a surveying payload for one of their flagship products the CyberQuad MAXI An
56. esigned to acquire 60 per cent forward overlap between photos along the same flight line and 30 per cent lateral overlap between photos on adjacent flight lines 7 Lateral Rom 20 to 40 Figure 3 Photographic Overlap 7 Photogrammetry The practice of determining accurate measurements from Point cloud PWM RC RMSE RPA SFM stereoscopic images Surface representation in the form of a set of three dimensional coordinate system Pulse width modulation Radio controlled Root Mean Square Error Remotely Piloted Aircraft Structure from Motion Using only a sequence of two dimensional images captured by a camera moving around a scene SFM allows the SLR camera SLS UAS UAV Uncontrolled VTOL reconstruction of the three dimensional scene geometry and the exact position of these cameras during image acquisition 8 Single lens reflex camera Selective laser sintering a 3d printing technology Unmanned Aircraft System typically referring to the entire system including Unmanned Aircraft UA Autopilot a Ground Control System GCS and data link between the UA and the GCS Unmanned Aerial Vehicle In this context it refers to images such as orthomosaics that have not been aligned to ground control points and as such the image cannot be accurately georeferenced Vertical take off and landing xi IV Acknowledgments The author of this report would like to thank the following people Murdo
57. evel ASL Above sea level CASA Civil Aviation Safety Authority CCD Charge coupled device Camera gimbal See Gimbal cm Centimetre CMOS Complementary metal oxide semiconductor CP Check Points DEM Digital Elevation Model is a digital representation of ground surface topography or terrain 3 DEM s can be divided into digital surface models DSMs or digital terrain models DTMs the distinction being DSMs contains elevations of natural terrain features in addition to vegetation and cultural features such as buildings and roads while a DTMs are bare earth model that contains elevations of natural terrain features only 4 Digital Surface Model KS Digitale Terrain Model Figure 1 Distinction between DSMs and DTMs 74 DG Direct Georeferencing DGPS Differential Global Positioning System Elevons Elevons are surfaces in aircraft that combine the functions of the elevator used for pitch control and the aileron used for roll control 5 Fiducial marks Fiducial marks are fixed points in the image plane that serve as reference positions visible in the image Focal length Distance from the optical centre of the lens to the focal plane when the camera is focussed to infinity viii GCP GCS Gimbal GIS GNSS GPS GSD IMU LIDAR MEMS MHz MILC mm MTOW OIS Orthomosaic Orthophoto For the purpose of this report DEMs and DSMs will be used collectively Ground Control Point An absolute reference point p
58. ference to set the aircraft as level 43 So that the servo is set to its middle position it is important to note that each time a parameter is changed the Write button must be clicked for the change to take effect Getting it as close to level as possible mechanically adjust the gimbal s rotation by changing the shaft s servo spline position A Hitec spline is shown in Figure 45 Each position should radially adjust the gimbal by approximately 10 44 Figure 45 Servo splines 44 Make fine adjustments to the servo s neutral position in MK tools to set the gimbal level A small spirit level greatly assists in determining if the gimbal is indeed perfectly level 34 Now that the gimbal is correctly levelled use an object to incline the airframe Adjust the compensation term in MK tools until the gimbal is again level as shown in Figure 46 and Figure 47 j e i e ke ef ae Figure 46 Gimbal calibration As a servo s response is linear this value should now allow the gimbal to be stabilized at any inclination however it is prudent to verify the value by changing the inclination of the aircraft and ensuring the gimbal remains level If the gimbal is compensating in the wrong direction select the reverse check box Finally adjust the Servo min and Servo max values to set the end points of the gimbal Manipulate the value to allow the maximum possible travel without the gimbal fouling on the
59. g RC input pulsewidth switchnow 0 switchnow starts at 0 ifpulsewidth gt Pllow AND pulsewidth lt Plhigh then switchnow 1 endif ifpulsewidth gt P2low AND pulsewidth lt P2high then switchnow 2 endif ifpulsewidth gt P3low AND pulsewidth lt P3high then switchnow 3 endif ifpulsewidth gt P4low AND pulsewidth lt P4high then switchnow 4 endif ifpulsewidth gt P5low AND pulsewidth lt P5high then switchnow 5 endif ifpulsewidth gt P6low AND pulsewidth lt P high then switchnow 6 endif return 69 E CHDK Camera Script while 1 do a get usb power until a gt 0 if a gt 5 and a lt 13 then gosub Switch1 if a gt 18 and a lt 22 then gosub Switch2 if a gt 28 and a lt 32 then gosub Switch3 if a gt 38 and a lt 42 then gosub Switch4 if a gt 48 and a lt 52 then gosub Switch5 if a gt 100 then print error wend end Switch1 shut down return Switch2 rem stick returns to centre do nothing print Neutral return Switch3 rem Zoom In print Zooming in click zoom in rem sleep 100 return Switch4 rem Single shot print Shoot shoot return Switch5 rem Zoom Out print Zooming out click zoom out rem sleep 100 return F HDMI Plug pin out Dynamic Display Clock Hotplug Detect Dynamic Display Data Figure 84 HDMI Pinout 36 EI Pin Function Number Pin 3 Pin 4 Pin 5 Pin 7 Pin 10 Pin 11 Pin 12 Pin 13 CEC Pin 14 Pin 15 Pin 16
60. g languages CHDK was loaded onto the S95 as per the instructions on the CHDK website 25 Figure 10 below shows the menus of a Canon S95 running CHDK Pa Script ES Load default paras values W Porometers set Ea Save par oms Ultra Intervaloneter Delay ist Shot Mins Delay ist Shot Secs Number of Shots interval Minutes Interval Seconds Interval 18th Seconds Ca La Z A Figure 10 S95 running CHDK 11 3 4 Autopilot Camera trigger interface cable For aerial photography and surveying applications the autopilot in a UAV must have some means of triggering the camera payload An adapter cable than can take a command signal from the autopilot and trigger the camera s shutter needed to be developed Standard radio control R C electronics such as receivers use a standard pulse width modulation PWM signal to drive servos electronic speed controllers ESCs and other devices The PWM signal has a fixed period of 20 milliseconds and the width of the pulse varied from 1 2ms governs the position of the servo or throttle As most autopilots interface with standard RC receivers and use servos and ESCs for control they too use standard PWM signals Figure 11 below shows standard servo operation Mini Maximum left inimum Pulse Width 0 5ms throw 45 90 degrees 5 Maximum right throw 45 90 degrees Figure 11 RC Control signal theory 78 As mentioned the CHDK firmware running on the camera ca
61. hat require more than 32 waypoints the mission has to be split into blocks of 32 waypoints and upon completion of each block the next set is uploaded inflight To assist in the flight planning a soreadsheet was developed that dynamically calculated flight parametersfrom the desired project parameters in a format consistent with the MK Tool waypoint generator By knowing the properties of the camera and the altitude the images are taken from it is possible to use first principles including basic trigonometry to calculate appropriate flight parameters given defined project parameters The relationship between camera properties ie sensor size and focal length the distance to the object and the field of view is core to many of the calculations within the spreadsheet and is best shown graphically in Figure 60 43 Camera body Focal length Flying Altitude Field of view Figure 60 Camera optical relationships Image scale 1 Flying Altitude m 1000 Focal Length mm Field of View width m sensor width mm Image scale Flight line spacing m 100 overlap Field of View width m 44 The spreadsheet contains three sheets The firstserved as the graphical user interface for mission planning Figure 61 Camera orientation Overlap idelap ixel size mm ixel scale cm px MK DelayTime s urvey site length m urvey site width m urvey Area m2 HDistanceX m WPs in X DistanceY m WPs
62. here all parameters are manually set and remain constant The focus should also be set to infinity so all features in the photo despite their height remain sharp assuming sufficient depth of field In aerial photography it is essential to get good image sharpness despite the movement of the aircraft which is achieved by using a high shutter speed Correct parameters were determined through experimentation starting with a sufficiently high shutter speed and test flying the camera while it was operating in Shutter Priority mode This allowed the camera to determine appropriate Aperture and ISO values The camera is then changed to Manual mode and the determined Aperture and ISO are used 3 Phase One Initial Development 3 1 Autopilot evaluation Since commercial autopilot development typically required tens of thousands of man hours and is usually supported by a multi million dollar budget it was decided from the inception of the project that an open source or commercial off the shelf COTS autopilot would be used After initial research a suitable autopilot was identified the Ardupilot Mega 2 0 is a sub 200 open source autopilot that is capable of fully autonomous 3D waypoint navigation and in flight uploading of commands using a two way telemetry link Mission Planner is the Windows compatible ground control station software which is used for autopilot configuration and flight planning 20 The Ardupilot board can control a
63. ied These systems are used in larger UAVs and digital video does have some distinct advantages in certain application over analogue video transmission namely the ability to encrypt a video feed a greater transmission range for a given power output and the ability to combine video and telemetry over a single link Unfortunately it was deemed that the drawbacks of digital video such as cost equipment sizeand video latency make them unsuitable for a CyberQuad being used in civil applications Another option was identified Use a HDMI to Composite converter board The specifications of various HDMI to Composite converter units were evaluated with minimal weight and size being the primary objective The unit purchased had the generic name of MINI HDMI to AV Converter and cost approximately S30AUD from an online shop The converter had a standard HDMI socket on 24 one side and composite video plugs on the other side The converter could be powered by the HDMI device connected or via a mini USB plug 5v The device initially measured 70x60x30mmand weighed 40g however it was de cased as shown in Figure 29 and the composite video plugs were de soldered reducing the size and weight to 65x55x10mmand 25g respectively Figure 29 HDMI to AV converter Unfortunately due to the minimal gap between the gimbal and the quad s ducts no HDMI cable could be sourced that would fit without fowling Figure 30 shows the compact nature of the gimb
64. in Y Grid Rotation Radius m Altitude m Waypoint Generator les Area Circle Panorama New Map Draw Grid OU D Distance X m 4 El HWPs inX is Gel Distance Y m 3 ite HWPs in Y 0 LN Grid Rotation DelayTime s Waypoint WPevent b Pa Radius m 25 Altitude m o 4 Heading 0 Gel Cam Nick P 30 8 Speed 0 1m s 30 2 Climb rate 0 1m s 2 A DelayTime s 100 A WP event P WP Prefix Iw Delete existing WPs Generate Not relevant to calculation Approx Storage required MB Approx Flight Time m Figure 61 Spreadsheet GUI The properties of the area being surveyed as well as the camera being used flying altitude and desired overlapare entered and the spreadsheet calculates the required parameters for inputting into the Waypoint generator Additional parameters such as the GSD and approximate flight time are calculated Excel s solver functionality could also be used to optimise mission parameters The second sheet contained a database of different cameras and their physical properties Figure 62 Camera NEX 5N 595 Other Mad Sensor height mm Pa a Sensor width mm Pixel height Pixel width Megapixels Average photo size MB Figure 62 Spreadsheet camera database The third sheet conducted many of behind the scenes calculations that generate intermediate values which were hidden as they were not relevant to the user Figure
65. ing a larger sensor size for its class of camera the S95 used high quality opticswhile still remaining compact It also had analogue video output Similar Canon cameras had been used in UAV payloads by various researchers including Y Han 2009 13 A Canon camera is also used on the Swinglet Cam UAV One of the best features of the Canon camera however was its compatibility with CHDK 3 3 CHDK Custom Camera Firmware CHDK is a custom firmware that runs on a range of Canon digital cameras CHDK is stored on the camera s SD card and loaded either manually or automatically into the camera s ram during each bootup It provides additional advantageous functionality that is beyond that provided by the camera s native firmware 25 Three particularly useful featured in this application are e Remote control o While most compact cameras do not have any means for an external trigger CHDK enables remote control through by sending a voltage to the camera s USB port 26 e Scripting and motion detection o CHDK allows the possibility of automating operation through writing scripts CHDK supports uBasic a Basic like language and also the more powerful Lua language 26 Scripts allow interaction with the camera including displaying data on the LCD and toggling LEDs reading the USB port state and simulating button presses Scripting allows for variables conditional statements subroutines functions and other features of typical programmin
66. ing the camera to manual mode with a predetermined shutter speed aperture and ISO sensitivity was experimented with but not tested The Canon S95 camera uses a proprietary USB connector for conventional USB connectivity as well as A V output The pin out of the connector had been reverse engineered with details published on the internet A break out board for the proprietary connector was sourced from Sparkfun 29 The pinout of the connector is as follows in Figure 13 1 USB VCC 5v Ze N C 3 N C As N C 6 9 11 5 5 USB GND O O O O 6 Video Out enable 7 8 10 4 T N C O O O O Se N C 1 2 3 Ers N C O O O 10 Video Out 11 Video GND Figure 13 USB connector pinout 79 A prototype circuit was developed Figure 14 and the code was downloaded to the PICAXE microcontroller using a FTDI USB to serial chip A detailed explanation of the FTDI chip is included in Appendix C Figure 14 Prototype trigger circuit 14 Following successful testing of the prototype a production version was developed Figure 15 This cable utilized surface mount resistors to minimise size used a LED to indicate when a command was triggered and by using the proprietary USB connector analogue video output from the camera was possible yellow and green wires Figure 15 Completed trigger circuit The equivalent schematic for the interface is demonstrated in Figure 16 Figure 16 Trigger circuit schematic Note that the FTDI programmer is only req
67. luding optical near infrared NIR thermal Imaging and multispectral systems and then subsequent photogrammetric data 63 processing using commercial and open source solutions To wrap the paper up case studies of UAV photogrammetry projects in archaeological environmental agriculture and mining applications are included Of particular relevance was the case study Estimation of the volumetric changes of gravel pits This paper helped greatly during the initial stages of the project literature review and helped identify many other papers that warranted further reading AN ACCURACY ASSESSMENT OF GEOREFERENCED POINT CLOUDS PRODUCED VIA MULTI VIEW STEREO TECHNIQUES APPLIED TO IMAGERY ACQUIRED VIA UNMANNED AERIAL VEHICLE 52 The researches in this paper used a multi rotor UAV much like the CyberQuad with a purely optical imagery payload to generate an extremely dense point cloud lt 1 3 cm point spacing This was achieved by flying at a very low altitude taking images with a high level of overlap and georeferencing the data with a large number of control points While their objective did not completely align with this thesis their data processing techniques including semi automatic GCP georeferencing justified further reading on the subject and the software used OPEN SOURCE IMAGE PROCESSING TOOLS FOR LOW COST UAV BASED LANDSLIDE INVESTIGATIONS 53 Again while the ultimate application of this research paper landslide investigati
68. minutes Despite the windy conditions the aircraft navigated well when flying down wind legs autonomously The flight path is shown in Figure 79 below lt gt ar kW Figure 79 Trial flight path The aircraft s position and other flight parameters were monitored on the ground control station and a live video feed from the CCD camera on the aircraft s gimbal was monitored to ensure the gimbal was correctly stabilizing the camera shots Before the flight fiducialmarkers unique patters that are identifiable in the captured images Figure 80 were placed around the perimeter of the stockpile to be used as ground control points and their coordinate ssurveyed using a total station 56 The flight data was processed by the surveying company who also used PhotoScan and the absolute accuracy was calculated to be sub 5cm The clients were satisfied with the result and this trial may lead to an ongoing partnership Figure 81 shows the images being processed in Photoscan H stockpile psz Agisoft Photosean 10 days lx ox File Edit View Workflow Tools Photo Help ep EI I x D 2es 00 ms Workspace sD A wd A Workspace 1 chunks 47 cameras Chunk 1 47 cameras 173218 points faces 199968 vertices 109000 DSC00415 JPG DSCO0416 JPG DSCO0417 JPG DSC00418 JPG DSC00419 JPG DSC00420 JPG DSC00421 JPG DSCO0422 IPG DSC00423 JPG DSC00424 JPG DSCO0425JPG gt KS Bi Ll MEN IE INS E A if EA i ES E
69. n Collector Lower row Gimbal Tilt Servo Output Servo1 Connector SV3 Upper row Servo3 Lower row Gimbal Roll Servo output Servo2 Connector SV4 Upper row Servo 5 Lower row Servo 4 4 7 Autopilot Gimbal Configuration Much like the fixed wing system previouslydescribed the gimbal had to be configured to ensure it had the correct neutral point travel range and stabilization gain to maintained level 33 Configuration of the gimbal is completed in the Camera tab of MK Tools Settings window Before going any further it should be noted that the flight controller uses a 8 bit microcontroller so many of the configuration parameters have a range of 0 255 2 128 being the middle value An extensive procedure for calibrating the gimbal s roll axis is given As the tilt axis follows a near identical procedure it is covered less thoroughly The calibration procedure is as follows 1 Ensure the CyberQuad is on a flat surface 2 Power up the transmitter and ground control station GCS then the CyberQuad 3 Ensure the open MK Tools on the GCS and ensure telemetry is connected 4 Calibrate and initialise the autopilot by moving the throttle yaw joystick in the upper left corner for until the buzzer beeps Figure 44 Throttle Yaw Pitch Roll Calibrate Figure 44 Transmitter calibration position 43 During this calibration the flight controller reads the gyro sensor values and uses the offsets as a re
70. n Sciences Volume l 3 Melbourne 2012 56 K a Y a Y L J T C L Y L C W M L Tsai a The Development of a Direct Georeferencing Ready UAV based photogrammetry platform in International Archives of the Photogrammetry Remote Sensing ai Spatial Information Sciences Volume XXXIX B7 Melbourne 2012 57 P R Wolf Elements of Photogrammetry International Edition Madison McGraw Hill Book Co 1983 58 W K Kilford Elementary Air Survey Glasgow Bell and Bain Ltd 1973 59 FTDI Chip FT232R USB UART IC Online Available http www ftdichip com Products ICs FT232R htm 60 ARC Electronics RS 232 Online Available http www arcelect com rs232 htm 61 CSIRO Light detection and ranging lidar Online Available http www csiro au Outcomes Food and Agriculture LightDetectionLidar aspx 62 S o E a Energy Engineering Thesis ENG460 Online Available http print handbook murdoch edu au units ENG460 Accessed 2012 63 Cyber Technology Payload Options Online Available http www cybertechuav com au Payload Options html Accessed 2012 64 Cyber Technology Technical Specifications Online Available http www cybertechuav com au Technical Specifications html Accessed 2012 65 RPS Group LIDAR Aerial Photography Online Available http www rpsgroup com au service lidar aerial photography Accessed 2012 66 K N Tahar AERIAL TERRAIN MAPPING U
71. n entirely cloud based service only requires a modern web browser and sufficient bandwidth to upload the images It is capable of generating impressive modelsappropriate for visualisation such as the stockpile in Figure 64 Hypr3D s basic feature set leads to some limitations however the generated models are low resolution and as it is not possible to georeferenced the images using Hypr3D the models are uncontrolled and it is not possible for the model s accuracy be determined As such Hypr3D is not suitable for engineering survey okma bo rks de D Stockp Cc www hypr3d com d o B books D Andrew Hazelden s MM Top 10 Highly Desir QB Top 10 Clever Tricks HN Geek to Live Set up DN Geek to Live Encryp BE An Interactive Devel C APM2 3 chdk C other CJ thess CJ UAV AP forums CI RC UAV 7 Business H O Other A DOT 4 4 d A Syn Sy MYO DESCRIPTION INFORMATION DOWNLOADS Login to download these model files New Hypr Factor Registration is fast and free images Uploaded images Used Total Points Textwe Prei IMAGES Figure 64 Hypr3D model 47 Hypr3D was used in this project for proof of concept model generation 5 2 2 Advanced Image Processing 5 2 2 1 Georeferencing Images To obtain survey grade data the processing requirements are more complex The first stage of processing is to use flight logs to determine the position and altitude of where the photo was taken to be embedded
72. n have up to a 5 offset in roll from horizontal to maintain a straight course Additionally it is not possible to capture images while banking during turns Figure 6 graphically demonstrates the benefits of active stabilization by showing the difference in imagery overlap from aircraft with active stabilization left and another aircraft that does not use payload stabilization right WM e ES u EC wg u Figure 6 Imagery overlap with and without stabilization 19 To compensate for these shortcomings these platforms have to fly at a large overlap typically 70 80 which dramatically increases the flight path length needed to survey a site ultimately limiting the area they can survey 2 6 Camera Fundamentals 2 6 1 Camera Settings Image exposure is a critical photography concept that relates to the amount of light reaching and thus what is actually captured by a camera s image sensor There are three adjustable elements that control the exposure Aperture Shutter Speed and ISO e Aperture is the lens diaphragm that regulates the amount of light that reaches a cameras sensor The wider the aperture the larger the hole the more light is let in during exposure A wider aperture will also reduce the depth of field sharp zone of focus which is undesirable for aerial photography e Shutter speed measured in fractions of a second is the time the sensor is exposed to light while capturing an image A fast shutter speed is desirabl
73. n trigger the shutter by reading the voltage state 0 or 5v on the cameras USB port Extra functions can be controlled by the use of scripts running on the camera that read the state of the USB port and interface circuitry sending pulses such a high for 50ms 100ms etc rather than a Boolean on off signal To convert the PWM signal coming from the autopilot to a high or low state required interface circuitry While a purely analogue circuit could have been developed that switches state if the PWM duty cycle reaches a certain threshold it was decided that microcontroller based solution would be easier to develop and allow pulses to be generated Additionally changing a circuit s functionality subsequently only requires code changes rather that a circuit redesign The PICAXE series of chips are based on Microchip PIC microcontrollersthat have been pre programmed with the PICAXE bootstrap firmware code 27 This allows the microcontroller to be re programmed in position directly via a simple three wire serial cable rather than an expensive conventional PICkit programmer 27 The 08M2 series in particular was selected for several reasons e Familiarity as it had been taught in ENG306 e Available in small 8 pin DIP package e Complete circuit only required the addition two passive components resistors as shown Figure 12 12 Figure 12 PICAXE 08 M2 minimum circuit 27 e Low unit cost The desired control functions
74. nannnnnononacnnonccnonacnonarnnnnrcnonocnoninnnns 10 Figure LOSIS FUN CHDK ee 11 Figure 11 RC Control signal theory 78 iii ti EERSTEN 12 Figure 12 PICAXE 08M2 minimum circuit 27 coooccccoccnnnocnnnncnnnncnnonacnnonononacononccnoninnnns 13 Figure 13 USB connector PINOUT E sidad AAA 14 Figure 14 Prototype FIP ser clic as 14 Figure 15 Completed trigger cra E ee eg 15 FIgure NR CCU Schema tE a a 15 Figure 17 Gimbal Inside EE 16 Figure 18 Gimbal stowed POSITION aiii bb 16 FISUre LO Praed GINO al nseries 17 Figure 20 Gimbal roll servo port configuration ccoocccncnocnncnncnnncnanononarononaroncnnacononaronenaronananos 18 Figure 21 Gimbal roll servo angle configuration oooccccooccncnncnnnononononacononaronnonanononarononaronananos 18 Figure 22 Camera trigger setting eege 18 FI2uUre 23 Boomerane 40 acera 83 luar 19 Figure 24 Failed elevator Sery O ninas tibia 19 FISure 2 S Crash timado 19 Figure 26 Mission Planner flight log analysis 20 Figure 27 CyberQuad Maxi with HD video payload T 21 Figure 28 Complete avionics stack showing GPS t FC Ctrl m and Navi b ooo 22 Figure 29 DMI TO AV el EE 25 Figure 30 Camera gimbal Mita aio 25 Fere LCUSTOM HONcode N 26 Figure 32 Sony OLED Electronic Viewfinder for NEX 5N Camera 37 ooccccncccinnccccnicnnno 26 Keure Glial With CCD CIME a ts 27 Figure 34 NEX 7 with mechanical Servo trigger Z 28 Figure 35 NEX 5Nmodified for elect
75. nd precisely known internal geometries and very low lens distortions allowing for very accurate processing 2 3 Project Objectives The ultimate aim of this project is to develop apayload for an unmanned aerial vehicle to capture aerial images and use photogrammetric processing techniques to generate geo referenced orthomosaics and digital elevation models DEMs of surveying grade Such an example is given in Figure 5 below 7k Pp Ve Wy lt 1MG_6839 PG DG G PG 1MG_6391 PG 1MG_6392 PG DG emt Pe IMG _6902 PG DG _ 903 PG k Wa g j MN f A F gt 1MG_6907 7G DG _6910 PG IMG_6912 PG 1MG_6914 7G IMG_6925 PG D 6928 7G Dap _6932 7G IMG_6933 76 IMG _6945 JPG IMG_69 PG DG Go SG IMG _6951 PG IMG Gesi Se MG 6958 JPG A GO 4 ERRI gt fant ee xsd Figure 5 Orthomosaic amp DEM generation from aerial Images 15 In designing the payload selection of components including camera actuators construction material and electronic componentswill be made and justified Other design choices such as whether the actuators driving the gimbal are geared or directly coupled will also have to be made Typically selection will be made by reading the manufacturer s datasheets though some components will be brought for evaluation and tested the empirical data collected will then be used for selection In addition the hypotheses that using a stabilized gimbal allows for more efficient flight plans as a lower lev
76. ne Available http www cybertechuav com au About Cyber Technology html Accessed 2012 3 Survey Graphics Mapping Consultants Australia DTM s amp DEM s Online Available http www surveygraphics com au dtm dem Accessed September 2012 4 Intermap Digital Elevation Models 2012 5 Unknown Elevon Online Available http en wikipedia org wiki Elevon 6 The State of Queensland Department of Environment and Resource Management Digital orthophot image data coverage September 2012 Online Available http www derm qld gov au property mapping ortho_keymaps qldmaster_ortho html Accessed September 2012 7 Natural Resources Canada Air Photos 101 Principles of Aerial Photography 25 September 2007 Online Available http www nrcan gc ca earth sciences products services satellite photography imagery aerial photos about aerial photography 891 Accessed August 2012 8 R Szeliski Computer Vision Algorithms and Applications Springer New York 2011 9 School of Engineering and Energy FINAL YEAR ENGINEERING THESIS 2012 10 B Triggs and P M a R H a A Fitzgibbon Bundle Adjustment A Modern Synthesis in Internation Conference on Computer Vision 99 11 J R U G Rock SENSITIVITY ANALYSIS OF UAV PHOTOGRAMMETRY FOR CREATING DIGITAL ELEVATIO MODELS International Archives of the Photogrammetry Remote Sensing and Spatial Information Sciences Vols XXXVIII
77. nline Available http photoshipone com 10 sony nex5n trigger modification Accessed August 2012 78 M Richling R C Control Signals Online Available http www mitchr me SS batteriesRequired RCcontrolTheory index html Accessed July 2012 79 kineteka HTC ExtUSB Breakout Mini Online Available http shop kineteka com p 94 htc extusb breakout mini Accessed August 2012 80 Mikrokopter Connect Camera Online Available http www mikrokopter de ucwiki en CameraConnect 81 Mikrokopter WayPoint Event Online Available http www mikrokopter de ucwiki en WaypointEvent 82 Unknown CloudCompare Online Available http www danielgm net cc 83 Strathalbyn Model Aircraft Club Boomerang 40 84 N McClanahan How to Program a PlCaxe with any FTDI cable Online Available http gadgetgangster com news 45 designer news 279 how to program a picaxe with any ftdi cable html Accessed 2012 Appendices A Annotated Bibliography UAV PHOTOGRAMMETRY 12 is a dissertation submitted to ETH ZURICH by Henri Eisenbei s for the degree of Doctor of Sciences Being one of the most valuable and detailed sources found It gives a detailed overview of the history of using UASs for photogrammetry the classifications of UAVs the advantages and limitations of different types of platforms including fixed wing multi rotor and helicopter It covers image data acquisition using different payloads inc
78. of the camera included being able to trigger photos retract the lens for landing and zoom in and out Using a PICAXE 08M2 an interface cable was developed that connected to one of the autopilot s auxiliary servo PWM output channels reading the pulse width In turn the PICAXE generating corresponding pulses that are multiples of 10ms in length whichwere fed into the camera s USB port The PICAXE program that was developed used code from a similar project published online that used a PICAXE 18M2 chip 28 Pseudocode for the PICAXE program is detailed below Declare input and output pins Declare RCpulsewidth thresholds DO MeasureRCpulsewidth If RCpulsewidth gt 0 and lt 2000 Oldpulse RCpulsewidth If RCpulsewidth Oldpulse 1fRCpulsewidth gt Pllow AND RCpulsewidth lt Plhigh then output 1 endif i1fRCpulsewidth gt P2low AND RCpulsewidth lt P2high then output 2 endif if output zU highoutputpin pausefor 100ms lowoutputpin endif endif output 0 RCpulsewidth 0 LOOP UNTIL OU The complete code is included as Appendix D 13 On the camera itself a script was developed that used the get_usb_power function to interpret the pulses as camera commands This script is automatically loaded when the cameras turns on The script is attached in Appendix E A more advanced script that in addition initializes the camera with default settings appropriate for aerial photography including disabling the flash sett
79. ons is one the payload being developed will unlikely ever be used for the use of open source processing software and the results of mosaicking aerial images without any ground control point information was of particular relevance UAV MAPPING A USER REPORT 54 This paper provided a first hand report in the use of a UAS for photogrammetry It gave an honest review of the capabilities and operational procedure of an existing commercial solution Some operational challenges that may not have been otherwise anticipated were identified and of particular interest was the finding that regarding ground control points GCP we observed that their need is application dependent For volumes no GCPs are needed Often it is enough to use 2 to 4 GCP for georeferencing the orthomosaic only 3D MODELLING AND ACCURACY ASSESSMENT OF GRANITE QUARRY USING UNMMANNED AERIAL VEHICLE 55 Surveying a quarry is an ideal example of a mission the payload being developed could be used for Again the researches in this paper used a multi rotor UAV much like the CyberQuad with a purely optical imagery payload UAVs proved an effective and economic method in comparison with other remote sensing techniques Camera calibration methods were explained and will be explored for this project SECRETS OF PHOTOMAPPING 19 Written by K Bosak a commercial UAV provider and operator Secrets of Photomapping is another incredibly useful resource It starts by comparing the
80. ony PJ710 Basic Block lt 1 gt Default lt lt Default gt _Disp Si Dual Head Assembly V16 lt 1 gt Default GI Ftrontech Mondo Extreme lt 1 gt Default lt lt Default gt _Displz Futaba S90705B Assembly lt 2 gt Default lt lt Default gt _Ap Futaba S9070SB Assembly lt 3 gt Default lt lt Default gt _Appea Se f CQ Maxi Lid VI6b lt 1 gt gt Default lt lt Default gt _Display f Camera Range Limits CQ Maxi Wide Assembly V16 Ko CQ Maxi DSLR Y Bracket V17 lt 1 gt gt Default lt lt Default gt E KE NEXSN Bracket lt 1 gt gt Default lt lt Default gt _Display Sta ES Ki DSLR NEX 5 Camera V1 lt 1 gt Default lt lt Default gt _Display Mates in CQ Maxi Wide Assembly V16 L Sensors E Annotations SolidWorks Premium 2010 x64 Edition Under Defined Editing Assembly H g Figure 42 Model with camera s FOV Once the density of the build material was entered Solidworks could calculate the mount s weight and centre of gravity In terms of the gimbal itself to reduce static load to the servos the centre of gravity of the gimbal and camera was designed to be as close to the centre of rotation of each axis as possible It was also possible to model how the payload s weight and position would affect the aircraft s centre of gravity The final design had a similar mass distribution to the existing high definition camcorder payload meaning that the airc
81. r efficient operation If a particular solar panel has a large temperature differential compared to others in an array it is evidence of a fault or sub optimal performance In extreme cases a faulty solar panel can act as a load to the rest of the array Currently thermal imaging is collected manually with a hand held camera but due the typically elevated location of solar panels collection is time consuming cumbersome and potentially hazardous with elevated work permits required Another application that can be pursued relates to agricultural surveying applications Y Han 2009 13 and other researchers have shown that due to the absorption nature of liquid in the near infrared NIR spectrum NIR cameras carried by UAVs can be used to assess the health of crops and use this data to predict crop yields 8 Conclusion In conclusion it was shown that unmanned aerial vehicles have proven to be a viable cost effective and safe platform for aerial surveying of sites in the order of low km being able to capture high resolution data at a professional survey grade The project drew upon electrical and mechanical engineering skills though as itwas an industry based thesis the project had learning outcomes that also included project management cost and time management and teamwork Initially a fixed wing platform was developed with an autopilot and an appropriate airframe selected A payload including a stabilized gimbal and camera trigger interface w
82. raft s centre of gravity was not altered by the new payload The final design had space for the HDMI to AV converter board and the infrared trigger As was the case with the Foamaroo s gimbal a secondary function of the gimbal was to protect the camera during a crash or hard landing by shrouding the lens Like the airframe the gimbal was 3D printed using SLS technology by a Melbourne based fabrication company The turnaround time from sending off the CAD file to delivery was under one week 32 4 6 Autopilot Gimbal Camera trigger Connection The flight control board has three double layer auxiliary connectors with servo and transistor switch outputs as shown Figure 43 Some servo outputs are designed for gimbal stabilization and others are general purpose Flight Ctrl ME 2 8 2 4 Top wuuMikrokopter cam Servo5 Bottom servo Recom ail j Top pam only for Servo ei E ervo supply ad om Bottom Fans o servaz Roll SPI to NC bi a de MES an KA B a ele CA KA k br Kl ee ge SCH CR anon w 18 Top coral 00 M temaza BOB e i Transitor utp Ms 255352 mal en EA E DEBERA sae a anda A wt Bottom CH D IERE Hr A PUT AT Servol Nick Te AA o BO Goo Serial Port Figure 43 MikroKopter Flight controller board auxiliary outputs 43 Connector SV2 Upper row Switching outputs Pin1 100mA switching output Transistor NPN Open Collector Pin5 100mA switching output Transistor NPN Ope
83. recisely located on both the ground and the photo found using conventional surveying equipment Ground Control Station A gimbal is a pivoted support allowing for the position of an object i e a camera to remain stationary despite movement of the supporting body i e an aircraft Geographical Information System A database system for analysing and manipulating geographical and statistical data Global Navigation Satellite System Global Positioning System Ground sample distance The actual distance between pixels centres projected onto the imaged surface Inertial Measurement Unit Light Detection and Ranging Meter Microelectromechanical systems Megahertz Mirrorless interchangeable lens camera unlike a digital single lens reflex camera a MILC does not have a mirror based optical viewfinder Millimetre Maximum Take Off Weight Optical Image stabilization in this context is an image generated by stitching multiple aerial images orthoimages An orthophoto is a geometrically corrected orthorectified photo such that the effects of aerial camera lens tip and tilt image scale variations and object displacements due to ground relief are removed 6 Overlap Orthographic view Perspective view ei LU Figure 2 Perspective vs orthorectified aerial image 73 Overlap is the amount by which one photograph includes the area covered by another photograph and is expressed as a percentage Conventional aerial surveys are d
84. rical triggering 77 o oocoooccnonoconncnonnnonaconenarononanos 28 Figure 36 The Swinglet CAM s camera Integration 29 Eet 29 Figure 38 HD Payload Base Plate and Y yoke ccccccsssecccsseceeesececeesceceeececeeseceseaecessunsesseaess 30 Feure 9 EE 30 Figure 40 GIMBDANSIZE CONSTE id AA AS AAA 31 Figure 41 Sola works MOON SUI s 31 Figure 42 Model with cameras EEN denge Ee is 32 Figure 43 MikroKopter Flight controller board auxiliary outputsl l eee eeeeceeeeeeeeeeeees 33 Figure 44 Transmitter calibration posttionl 2l 34 A O O 34 REI REH Teen VE 35 Fieure 47 MiIK TOO eimbal conte UFAtION ai On 36 Figure 48 Waypoint trigger configuration cccoocconononnnonarononanonnnnacononarononanonnonarononaronenaronennnos 37 Figure 49 Waypoint trigger configuration Conte 37 Figure 50 Trigger switch configuratiQN cccoocccccnonnnonanononacononnnonnnnncnnonarononnrnnnonarononarononarononanos 38 Figure 51 ArduCopter roll axis stabilization control loop Jl 38 Figure 52 WMI TOO SScope TUNCUON EE 39 Figure 53 MikroKopter TURING parameter nadaa ais 39 Figure 54 MKGPX OU AT di tater cece iach etd sete eta doer a a ates a 40 Figure SEET TEEN 41 Figure 56 MISSION WOFKTIOW 12 ess a 42 BA ai Ee e OS Dia enone ace T 42 Figure 5S Waypoint Generator Alida AAA 43 FIgure 59 MK Toolupload Ee e e EE 43 Figure 60 C mera optical relationships iii ii ii 44 Figure 61 Spreadsheet GU ia as 45 Figure 62 Spreadsheet Camera d
85. riggering CONTEUFA ION ii 36 49 AUTODUIOT oU EE 38 ALO ISSUES FACOG anar 40 5 Phase Three Mission Planning data collection and Processing cccccsseceesseeeeeeeeees 42 e CR ERT ei DEN Te ln EE 42 izo Data PROCESS Pri 47 9 2 Ly Basic Model Generation lid 47 9 2 2 Advanced image Protesis a 48 6 Phase Four Testing ana Case UI er E 52 A A O aches 52 6 2 Case Study Mapping an e ln BEE ele gn 56 Te FUO WOK ee 58 S CONCISO Neta ci di 58 Ol gt EE dee 60 APENAS lt ita td 63 E effet Ee Melle ele EE 63 B Camera Evaluation Bel E EE 65 C Programming the PICAXE Microcontroller ooooccccoocncnonocnnonacononanonnonacononaronenanonos 66 D PICARESPLOB Mi A AAA AAA 67 Ex TRADE Camera SC o eo ao aio ide OL 70 Es ai DAT le OU EE 71 I List of Figures Figure 1 Distinction between DSMs and DTMsS 74 ccooccccnnccncnccnnnccnonaccnonononacononacnnnacnnno viii Figure 2 Perspective vs orthorectified aerial magel 3l X Figure ProtograpaicOvenap Mi aa X Figure 4 Photogrammetric technologiesand their application 12 oooooomomommmmmmommoo 2 Figure 5 Orthomosaic amp DEM generation from aerial Images 3 Figure 6 Imagery overlap with and without stabilization 19 oocoooocnncnononnnnnnnnnnnnss 5 Figure 7 Funjet UAV platform with the Ardupilot mmtegrated 8 Figure s The Foamaroo EELER lege 9 Figure 9 Relative Camera Sensor sizes 75 ocooncnnnncninncnno
86. s System Figure 9 Relative Camera Sensor sizes 75 e Optical Image stabilization o OIS is used in cameras to reduce image blurring caused when the camera is moving during image exposure It works by varying the optical path to the sensor OIS works well for low frequency motion such as the movements of a photographer while they are taking a photograph however OIS is not designed for cases of high frequency vibrations such as when being mounted on an UAV and can degrade image quality o For precise results in photogrammetry a camera must be calibrated However the OIS mechanism even when electronically disabled can still minutely move which alters the optical path to the sensor and changing the cameras parameters e AV out o Alive video downlink allows an operator to monitor and aim the payload Such a feature is critical for Inspection work but also useful for surveying applications In addition to being able to frame the picture the camera s on screen display OSD provides important information such as the camera battery level and remaining memory e External stutter triggering o The aircraft s autopilot has to be able to trigger to camera s stutter A camera with an electronic interface means mechanical modification does not need to be done e Battery Life e Cost 10 A Canon S95 a high end compact camera was available for use in this project It wasn t chosen solely because of it availability In addition to hav
87. s the imagery The raw imagery is then processed by photogrammetry software to generate orthomosaics and digital elevation models DEM s This workflow is summarized in Figure 56 below Project parameters Selection of the UAV system Flight parameters Flight mode Quality check of the data Position and Orientation DSM Orthoimages 3D Models etc Figure 56 Mission workflow 12 5 1 Flight Planning Flight plans are generated and managed by the MK Tool software within the OSD window To generate a flight plan open the software and navigate MikroKopter Tool gt OSD clicking on the WayPoints tab and finally on Generator 49 Figure 57 Imagesize 774x393 Position 0 997455 0 400517 File Data Link WayPoints Display GPS coordinates Editor Generator Add MK Pos to WP list Figure 57 MK Tool OSD A Waypoint Generator window opens allowing flight parameters to be entered The windows and parameters are demonstrated in Figure 58 42 Waypoint Generator En e Distance X m This is the distance in meter between each Waypoints in X Direction New Map Draw Grid tg Distance Y m This is the distance in meter between each Waypoints in Y Direction A WPs in Y Number of Waypoints in Y Direction 20 A Distance z m l Grid Rotation Orientation of the grid relative to North Dependent on 2 A HWPs in x a 23 A Distance Y m 3 SI HwPs in Y Radius m R
88. sed Camera Selection With the increased funding and a completely different aerial platform being used camera selection was re evaluated in collaboration with other engineers at Cyber Technology The CyberQuad had a larger payload capacity that allowed for a more capable camera to be selected Using the same metrics as before starting with the payload capacity of the CyberQuad as the primary constraint the Sony NEX 5N was chosen Comparing the NEX 5N to the S95 the NEX 5N had some significant advantages e Uses fixed focal length lens e More than 60 better image qualityhigher resolution 16 MPvs10 MP e Better maximum light sensitivity 25 600 ISO vs3 200 ISO e Less shutter lag235msvs610ms e Much faster max shutter soeed1 4000svs1 1600s 23 Other relevant specifications are now listed in the Table 3 Make and Model Canon S95 Sony NEX 5N Picture Sensor Helght mm 76 iss i i 1 5 Composite analogue Video Out HDMI Output Price with Lens AUD 850 Battery life CIPA rating 200 shots 430 460 Table 3 Camera specifications 4 3 Video Output The NEX 5N has digital video output via a mini HDMI port on the left side of the camera As the video transmitter on the CyberQuad is designed composite video input at 1Vpeak to peak with 75 ohm impedance this presented a problem Digital video transmitters were researched and products such as the Teradek Cube 34 and the Lockheed Procerus IP Data Link 35 were identif
89. suffer from a number of limitations e These platforms are a compromise between size as they must be easily transported and ease of use they require limited assembly for deployment These constraints have ultimately led to single piece wing airframes that belly land e The swingletCAM has a payload capacity of just 150 grams only enough for a low end point and shoot camera and can only operate in winds up to 25 km h 17 severely limiting the platform s versatility e The Gatewing is a larger platform and as such can carry a higher resolution camera with better optics the Ricoh GR and can fly in stronger winds up to 60km h To enable it to do so the Gatewing carries a significantly larger battery 11 1 V 8000 mAh and has a significantly higher wing loading As a consequence the aircraft has a high stall speed of 45 km h meaning it must land hot and requires a 100 x 30 m flat landing strip 18 Gatewing quotes the lifetime for an X100 airframe to be just 30 4 flights at which point the avionics must be transplanted into a new airframe costing approximately 3000 AUD As the camera on both platforms is rigidly coupled to the airframe the quality of the imagery both platforms capture deteriorates as the weather conditions become more adverse wind gusts will buffet the aircraft causing the camera to no longer be orthogonal relative to ground Even when navigating in a straight line if there is a crosswind a small aircraft ca
90. taken off and landed under manual control though once programmed autonomous flights occurred along a predefined path Typically flights comprised of three strips in a West to East direction taking varying numbers of images along each strip An example of a flight path is given in Figure 70 A h Y D ga oul gt Figure 70 Example flight path at the test site To calculate the accuracies of the models that have been generated surveyors were contracted to conduct a ground control point survey This data is used as a ground truth during processing allowing a respective model s accuracy to be determined Figure 71 shows a licensed surveyor using a theodolite to collect GCPs 52 Figure 71 GCP survey Unfortunately due to contractual disagreements between Cyber Technology and surveying company the GCP survey data was not provided in time to be used in processing This meant that the original method for testing the effectiveness of the stabilized gimbal was not possible Comparing the raw captured Figure 74 to that available from other public sources it can be seen that the imagery is of higher resolution Google Maps imagery Figure 73 of the site offers limited resolution and dates back to 5 5 2008 and the site has since been completely redeveloped Nearmap provides far more up to date 30 6 2012 imagery Figure 72 however it has limited resolution and mosaicking artefacts exist Wwe entity Figure 73Nearmap Im
91. tal stills cameras with IR capability It can be triggered directly from a standard Radio Control RC system or by any switch contact via the blue wire Comes with a 25cm 10 3 pin standard servo lead amp weighs 4grams 41 emm Figure 37 gentLED SHUTTER 41 4 5 Gimbal Design Unlike a fixed wing which is mostly unstable in the roll axis the dynamics of the VTOL aircraft meant that the gimbal needed to be both pitch and roll stabilized The CyberQuad s autopilot limits the aircraft s maximum pitch and roll to 30 from the horizontal The design of the gimbal was an iterative process each revision being tested and refined until the designed constraints were met The following pages document this process 29 After internal discussion and meetings with surveying partners it was determined that the gimbal must maintain the modular design allowing it to be easily interchanged with other payloads such as HD camera payload Figure 38 Y yoke Base Plate Figure 38 HD Payload Base Plate and Y yoke This meant the gimbal had to use the existing roll stabilized base plate and preferably use the same Futaba S9070SB servos that were used in existing payloads The following design constrains were identified e Gimbal must usethe existing roll stabilized baseplate e Unobstructed movement around the axes of rotation must be o Roll 30 from horizontal o Tilt 40 from vertical e Ensure the quad s ducts di
92. topilot Configuration of the Ardupilot is done using the Configuration tab within the Mission Planner software Payload specific configuration is done thought the StandardParams sub tab The roll servo and camera trigger cable were physically connected to the Ardupilot s auxiliary servos outputs 5 and 6 respectively and declared Figure 20 Servo out function RC5 FUNCTION Description Setting this to Disabled 0 will disable this output any other value will enable the comesponding function mount roll Servo out function RCS FUNCTION Description Setting this to Disabled 0 will disable this output any other value will enable the comesponding function camera_tngger Figure 20 Gimbal roll servo port configuration Following this declaration the Camera Gimbal sub tab becomes visible within the Configuration tab and allows the roll angle limits to be configured Figure 21 Stabalise Roll Figure 21 Gimbal roll servo angle configuration Autonomous mission planning is conducted in the Flight Planner tab The DO_SET_SERVO command can be used to trigger the camera at each waypoint Figure 22 Figure 22 Camera trigger setting 18 3 7 Further Test Flights At this point in the project the Foamaroo had not been delivered and its absence was holding up the project After communicating with the manufacturer it was found that the aircraft was in fact still being constructed As such
93. tric literature the PICAXE manual 27 greatly assisted in developing the autopilot gt camera shutter interface cable which uses a PICAXE microcontroller The Canon Camera Hackers Manual 26 was heavily relied upon in learning how to load a custom firmware onto the Canon S95 camera and develop scripts that run on the camera automatically configure certain parameters on start up and allowing the shutter interface cable to work B Camera Evaluation Spreadsheet Refer to 3 2 Camera Selection x 5 E CyberQuad Payloads 201200809JNP Microsoft Excel Hom Insert Page Layout Formulas Data Review View Add Ins F a e LN e M e LR w a Colors T y FS E Fa Tas Width Automatic Gridlines Headings As A Das aa gg eem S a E A Fonts al Height Automatic Idi View Y View Them Margins Orientati Size Print Breaks Background Print a Bring Send Selection Align O Effects v D Area H Titles tk Scale 100 7 Print Print Forward Backward Pane Themes Page Setup Scale to Fit Sheet Options Arrange E26 M f E PATAS ay TS TS TZ Ta TS To Tu TI tist Tia Tis Tie TT Ta T 71 25 T2 127 A B Cc D F a Make and Model Canon EOS M Pentax E H oom P Picture Epa E 3 Effective Pixels MP 17 9 ja Sensor Width mm 22 3 L 5 Sensor Height mm 14 9 GLP Body Dry Weight g 220 4 298 with battery ki 7 Functional Weight g TBA 403 8 Body
94. uired during programming 15 3 5 Roll stabilized Gimbal Design Figure 17 Gimbal inside fuselage A gimbal was designed using Solidworks an industry standard computer aided design package The gimbal was designed to fit within the Foamaroo s 3 5 inch 8 89cm cylindrical fuselage Figure 17 In addition to stabilizing the camera to ensure its lens was always orthogonal to the ground the gimbal was designed to safely stow the camera at 90 while the aircraft was taking off and landing thus protecting the camera lens from potential damage Figure 18 Figure 18 Gimbal in stowed position 16 As the Ardupilot was configured to have maximum limit of 30 when flying in autonomous mode the gimbal was designed to allow it to have 30 roll travel for stabilization and 90 giving 120 of total travel stowing the camera during take off and landing A servo was selected for roll actuation as it could connect directly to the autopilot via the auxiliary servo output ports Stepper motors were investigated though the benefits of their increased precision were found to be mitigated by their increased weight and increased complexity of control circuitry Geared or pulley driven systems which could improve torque and position resolution were also investigated though such solutions would increase the weight and mechanically complexity of the gimbal Additionally 135 travel was near the full range of the servo so gearing down the mov
95. width using RC transmitter and uncomment debug functions to find thresholds or test output behaviour Vx x Connections RC 5v to VDD pin 14 RC Ov to VSS pin 5 e RC Pulse read on C 2 pin 1 Ken USB for camera 5v on VDD pin 14 Vo USB for camera 0v on C 7 pin 16 UK VKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK kkkEkEkkkk kk symbolpulsewidth w13 measured width of Channel 1 RC input pulse symbolswitchnow b6 used to store the current RC decode symbol lastusb b7 used to store the last USB power pulse type sent only changes in input pulse result in a USB power pulse symbolswitchlast b8 records the last switch value decoded symbolswitchcount b9 the number of same switch decodes in a row symbol times wll symbol state b12 symbol result b13 VKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK x RCpulselength thresholds VKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK KKK KK AAA RAR symbol Pllow 750 below this and pulse not valid symbol PlHigh 990 max width of RC Switch 1 pulse symbol P2Low 1000 min width of RC Switch 2 pulse symbol P2High 1200 max width of RC Switch 2 pulse symbol P3Low 1400 min width of RC Switch 3 pulse symbol P3High 1550 max width of RC Switch 3 pulse symbol P4Low 1650 min width of RC Switch 4 pulse symbol P4High 1800 max
96. yberQuad utilized for this project used a German based autopilot called the MikroKopter The complete MikroKopter avionics stack shown in Figure 28 consists of the Flight Control board the Navigation Control Board and GPS The Flight Control board FC Ctrl is the main processing board which uses a three axis MEMS gyroscope 3 axis accelerometer and barometric pressure sensor to maintain smooth 21 level and controllable flight The R C receiver via PPM sum signal telemetry modem via UART and the motors via an I C bus are connected to the FC Ctrl For 3D navigation such as position hold return to home and waypoint the quadcopter requires the Navigation Control Board Navi Ctrl which has an additional 3 axis magnetometer and a GPS module MK GPS The GPS communicates with the Navi Control via UART which in turn communicates with the FC Ctrl via an SPI bus e e trge _ aaa S A Leg Figure 28 Complete avionics stack showing GPS t FC Ctrl m and Navi b The Navi Crtl board has a microSD card slot that allows flight parameters most importantly time GPS coordinates altitude and heading to be logged in GPX format 31 It is important to note that the time recorded is in Coordinated Universal Time UTC The logging interval can be changed by altering the GPXLOGGING value in the Settings ini file located on the root directory of the SD card GPXLOGGING 1000 Interval in ms the logging of the G

- Murdoch Research Repository

Contents

Download Pdf Manuals

Related Search

Related Contents