Contents. Cameron Ellum and Prof. Naser El- Sheimy 19 April 2005 mobile multi-sensor systems research group

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1 The Coon Adjutent of GPS and Photograetric Caeron Ellu and Prof. Naer El- Sheiy 19 April 2005 obile ulti-enor yte reearch group Content Background Reearch objective Ipleentation Teting Concluion Outlook 2 obile ulti-enor yte reearch group GPS controlled photograetry Firt enviioned in the id-eightie Heavily reearched throughout the id-tolate eightie Coercially operational ince the early ninetie Datu definition Expoure Object pace point Mapping co-ordinate yte eaureent Terrain Traditional photograetry Expoure GPS controlled Photograetry Object pace point Mapping co-ordinate yte eaureent Terrain 3 obile ulti-enor yte reearch group 4 obile ulti-enor yte reearch group Including GPS data in the adjutent GPS data i included in the photograetric adjutent a proceed poition, uing paraeter obervation equation: Shift (b) and drift (d) ter are intended to account for incorrect abiguity reolution; ay alo account for datu tranlation GPS controlled photograetry Advantage: Allow for a reduced nuber of ground control point potentially none, if tie to an exiting datu are not required Reduce cot and turn-around tie Can increae accuracy, and reulting network ay have ore hoogenou accuracy 5 obile ulti-enor yte reearch group 6 obile ulti-enor yte reearch group 1

2 Reearch Objective: Liitation of current technique The haring of inforation between the photograetric and navigation proceor i trictly oneone-way. way The navigation proceing trea doe not benefit fro the photograetric data. Current integration trategie have alway preuppoed differential GPS. The poibilitie of undifferenced GPS have not been exained. The traditional hift-and-drift approach for including GPS data aue that incorrect abiguity reolution anifet itelf a a linear error. In reality, thi i not the cae. obile ulti-enor yte reearch group 7 Cobined adjutent Cobine the raw GPS eaureent and photograetric eaureent in a ingle adjutent Enable GPS data to be ued even when le than four atellite are viible Siplified, ingle-tep proceing Ultiate goal: utilie photograetric network to aid GPS abiguity reolution Hopefully, will iprove accuracy and, ore iportantly, reliability obile ulti-enor yte reearch group 8 Ipleentation: Ipleentation: Undifferenced or double-difference range Code range or carrier phae range Ipleentation of the cobined adjutent i ade eaier by recating the collinearity equation o that they like the GPS obervation equation are explicitly function of the GPS poition: Additional advantage: Cobined adjutent overview Modified collinearity equation GPS GPS GPS/Photograetric GPS/Photograetric Adjutent Adjutent Real abiguitie Integer abiguitie Abiguity Abiguity earch earch engine engine obile ulti-enor yte reearch group 9 Ipleentation: Receiver clock offet are added to the adjutent a additional paraeter Double-difference code range obervation equation Double-difference carrier-phae obervation equation 11 obile ulti-enor yte reearch group Cobined adjutent fraework Undifferenced code range obervation equation: 10 Ipleentation: GPS Obervation Equation Sipler paraeter obervation equation: GPS poition can directly be ued a initial approxiate Multiple-caera yte only need a ingle poition olved for per epoch No additional paraeter Double-difference abiguitie are added to the adjutent a additional paraeter obile ulti-enor yte reearch group 12 obile ulti-enor yte reearch group 2

3 Teting: Data et decription Teting: Noinal cenario Aerial photograetric block 42 iage, 7 flight line pixel Field of view 37 Flying height 900 Sidelap 30% Endlap 60% 53 control/check point Ground controlled network Double-difference carrier phae expoure tation poition Mean Std. dev. Mean Std. dev Noie level of 15c horizontal, 35c vertical 13 obile ulti-enor yte reearch group 14 obile ulti-enor yte reearch group Teting: Soothed, undifferenced code range Teting: Soothed, double-difference code-range Cobined adjutent ean td. dev Poition obervation ean td. dev Poition obervation ean td. dev Cobined adjutent ean td. dev Sae data, lightly iproved reult Virtually the ae Cloe to bet reult poible fro the network 15 obile ulti-enor yte reearch group 16 obile ulti-enor yte reearch group Concluion Optiit With undifferenced obervation, accuracy iprove Peiit With double-difference, no change Realit Inconcluive, ore teting required Reult are enitive to relative weight on iage eaureent and GPS range Cobined adjutent Ultiate goal: Iprove reliability GPS abiguity reolution A negligible or non-exitent accuracy increae i okay, if the above two goal can be et 17 obile ulti-enor yte reearch group 18 obile ulti-enor yte reearch group 3

4 Inforation haring between proceor Inforation haring between proceor Two-way haring of inforation between a photograetric adjutent and a kineatic GPS proceor Kalan-filter-baed kineatic GPS proceor will provide poition to the photograetric adjutent Photograetric adjutent will, in turn, provide poition update (and covariance) to the Kalan filter Navigation filter i aided by the photograetric adjutent Real abiguitie GPS GPS GPS Kalan Filter Abiguity Abiguity earch earch engine engine Integer abiguitie Poition, covariance Bundle Adjutent Kineatic odel i retained Adjutent operate equentially 19 obile ulti-enor yte reearch group 20 obile ulti-enor yte reearch group Acknowledgeent Tet data provided by Applanix Corporation Ipleentation: Atopheric error itigation Tropophere UNB3 zenith delay odel Neill apping function Financial upport fro: Killa Trut NSERC The Killa Trut Ionophere Not itigated becaue of reulting increae in noie Orbit and clock Not itigated becaue it priarily introduce a bia, and becaue it difference out in the double-difference obervation 21 obile ulti-enor yte reearch group 22 obile ulti-enor yte reearch group Ipleentation: Cobined adjutent oftware Soe tatitic: Line of code > 83,000 Exiting GPS/INS proceor < 33,000 Goal: aintainability and extenibility Adjutent progra ha been divided into individual adjutent odule connected in a hierarchical fahion Photograetric adjutent GPS adjutent Terretrial network adjutent Ipleentation: Cobined adjutent fraework Each ub-adjutent ake a few generic routine available to the parent adjutent The parent adjutent then only ha to call the routine in the appropriate order The adjutent inherit a generic behaviour fro a coon bae, or, when neceary, ipleent their own cuto behaviour. Progra i ore aintainable: Individual adjutent can be teted and debugged in iolation. Inheritance and polyorphi reult in le code 23 obile ulti-enor yte reearch group 24 obile ulti-enor yte reearch group 4

5 Ipleentation: GPS Adjutent The GPS proceor ued in the cobined adjutent ha a nuber of idioyncraie: The expoure event likely don t coincide with GPS eaureent, o the proceor can interpolate GPS eaureent between actual eaureent epoch. None of the GPS tation need to have fixed coordinate. The datu for the entire network can be controlled by inforation coing fro another child adjutent. 25 obile ulti-enor yte reearch group 5