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Precise relative positioning in machine swarms. Motivation and Introduction IMU/GNSS and Vision integration Swarm Positioning Mobile Ad-Hoc Communication First Results Conclusion and Outlook. Outline. Motivation . Urban and alpine scenario
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Motivation and Introduction IMU/GNSS and Vision integration Swarm Positioning Mobile Ad-Hoc Communication First Results Conclusion and Outlook Outline
Motivation Urban and alpine scenario • Shadowing of GNSS signals, degradingGNSS signals, multipath effects • Guidance with the help of known landmarks is limited • Fast search with high accuracy positioning Integration of IMU/GNSS including Failure Detection and Exclusion Methods Vision-aided relative localization Swarm Positioning using GNSS raw data exchange Mobile Ad-hoc communication for GNSS raw data exchange
Introduction – “NExt UAV” Joint research project “NExt UAV“ Institute of Flight Guidance Institute of Agricultural Machinery and Fluid Power Institute of Flight Systems Fundedby FKZ 50NA1002 and50NA1003
Motivation and Introduction IMU/GNSS and Vision integration Swarm Positioning Mobile Ad-Hoc Communication First Results Conclusion and Outlook Outline
IMU/GNSS and Vision integration - FDE • System architecture • Main filter processes all measurements (N) • Each subfilter processes (N-i) measurements (i = 1…N-1)
IMU/GNSS and Vision integration – Vision based localization
Correction Prediction IMU/GNSS and Vision integration - Coupling Monitoring INS/GNSS GNSS IMU Tight coupled Predicted Feature World Position Feature Pixel Position Predicted Pixel Position Feature World Position Vision
Motivation and Introduction IMU/GNSS and Vision integration Swarm Positioning Mobile Ad-Hoc Communication First Results Conclusion and Outlook Outline
Swarm Positioning - Standalone rover b rover a
Swarm Positioning – Double Differential rover b rover a
Swarm Positioning – Standalone & Double Differential rover b rover a rover c
Motivation and Introduction IMU/GNSS and Vision integration Swarm Positioning Mobile Ad-Hoc Communication First Results Conclusion and Outlook Outline
Mobile Ad-Hoc communication - Requirements • Quick and safe data exchange • Flexible for dynamic changes in network topology • Decentralized system to compensate loss of swarm participants • MANet or Mesh networks • Scenarios: All2All, All2One, One2All Without direct data linkDirect data linkMulti-hop data link
Mobile Ad-Hoc communication - Simulation • Using MATLAB® • Proactive routing – All2All • 4 to 12 nodes • 1000 simulations • Steps: • Generate random network • Network discovery • Routing • Data Exchange
Mobile Ad-Hoc communication - Implementation • Network exploration • Calculating the routing table • GNSS raw data exchange • Data processing
Mobile Ad-Hoc communication – Network Exploration • Problem: No a-priori knowledge and no coordinator Try and Error • Tools: Clear Channel Assessment (CCA) • Scan energy level of channel • Compare detected energy with threshold • If medium not clear wait random backoff time and try again • Problems: • Hidden stations • No ACK available using broadcast messages
Motivation and Introduction IMU/GNSS and Vision integration Swarm Positioning Mobile Ad-Hoc Communication First Results Conclusion and Outlook Outline
First Results – Reference systems • Reference localization system (Leica Viva TS15 ) • tracking with up to 6 Hz • compare track with GNSS/INS solution • Sync by GNSS-time using WLAN and NTP • Phase solution in post-processing UAV 2 UAV 1 Ref-Station UAV 3
Motivation and Introduction IMU/GNSS and Vision integration Swarm Positioning Mobile Ad-Hoc Communication First Results Conclusion and Outlook Outline
Conclusion and Outlook • Absolute and relative position is indispensable • Positioning techniques and controlling strategies requireswarm communication • Algorithm for network exploration fits simulation results • Test of all sub-systems together in one system • Tests in different scenarios (urban, alpine, different constellations) • Optimization of the required time minimization of the required messages
Thank you for your attention! Institute of Agricultural Machinery and Fluid Power www.tu-braunschweig.de/ilf ilf@tu-braunschweig.de comRoBS Dipl.-Ing. Jan Schattenberg J.Schattenberg@tu-braunschweig.de Tel.: +49 (0) 531 391-7192 Fax: +49 (0) 531 391-5951
NExt UAV - IMU 2x dual axis MEMS acceleration sensor (Bosch SMB225) 3x 1-axis gyro sensor (Bosch SMG074 )1x “read-out”-board layout and design by IFF NExt UAV - GNSS µblox LEA-6T-chip (Precision Timing & Raw Data) Hybrid GPS/SBAS engine (WAAS, EGNOS, MSAS) Basis-Board layout and design by messWERK Technical Equipment
Technical Equipment NExt UAV- NAV-Board • Seco Qseven™ Embedded Computer Module • Pico ITX-Standard (3,9”x2,0”, 100 x 72 mm) • Intel Atom (Z530) 1,6 GHz, 1 GB DDR2, 800 Hz bus • 8 GB Flashdrive, microSD-Slot (8 GB), SD-Slot (8 GB) • Operating system: linux with real time extension NExt UAV- Radio module • Wireless standard 802.15.4 XBee • Frequency Band 2,4 GHz ISM • Radio range up to 1.6 km • Serial Data Range up to 115.2 Kbps
Technical Equipment NExt UAV- Vision • 2x AlliedVisionTec Marlin F-131B with Pentax C815B • Self-made carrier for stereo camera system • Interface: IEEE 1394a - 400 Mb/s • Resolution: 1280 x 1024 • 25 fps on full resolution NExt UAV- Vision-Board • Lippert CXR-GS45 PCI104Ex with Core2Duo 9300 • 2 GB Ram • Firewire expansion board