Relative Positioning of Unmanned Ground Vehicles Using Ultrasonic Sensors
Type of DegreeThesis
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In this thesis, a Global Positioning System/Inertial Navigation System (GPS/INS) is developed and applied to a tracked Unmanned Ground Vehicle (UGV) to provide estimates of position, heading, and velocity. The navigation estimator is then augmented with ultrasonic sensors to accurately determine the relative position of a pair of tracked UGVs. The estimator provides estimates on critical system parameters to allow for automation or collaboration. The capabilities of UGVs can be greatly increased through automation and collaboration of multiple UGVs. Automation reduces the operator workload and allows the UGV to continue operations during a loss of communication. Collaboration allows multiple small UGVs to accomplish tasks previously requiring a single large UGV. A microcontroller uses the ultra-precise Pulse Per Second (PPS) from the GPS to trigger the ultrasonic sensors. This configuration minimizes the problems traditionally encountered with use of ultrasonic sensors in an outdoor environment while providing additional information to the navigation estimator. Small, low cost sensors using MEMS technology are employed to minimize size and cost, providing a solution that can be implemented on current UGVs. Experimental results are presented to compare the performance using GPS alone, GPS/INS, and GPS/INS/Ultrasonic sensors for estimating relative positions and headings of multiple UGVs.