GPS World, February 2016
ANTENNAS CHARACTERIZATION GUIDES UAV NAV reception pattern which resulted in very noisy measurements Of the three max3 and cross correlation fared the best in the ideal distance from the signal source Max3 was able to outperform cross correlation when the UAV was far from the signal source due to the limitations of cross correlation requiring a truth pattern for correlation However cross correlation can also provide a useful correlation coefficient that can be used in the future to merge several bearing calculation methods The characterization of antenna bearing performance is a vital component to the localization process The characterization affects the optimal behavior determined by POMDP When we changed our initial assumptions about measurement performance near the jammer to one better informed by our tests the actions determined POMDP resulted in a significantly different profile ACKNOWLEDGMENTS The authors gratefully acknowledge the Naval Postgraduate School for providing an unmatched space to be able to perform test flights of the JAGER system at the Joint Interagency Field Experimentation events The authors would also like to thank the Stanford Center for Position Navigation and Time SCPNT and its members for supporting this work MANUFACTURERS The JAGER UAV airframe is a S1000 octocopter by DJI Innovations the flight batteries are a 8000 mAh model by Hextronik the autopilot hardware and GPS antenna is a Pixhawk by 3D Robotics Inc the autopilot software is based on PX4 by Pixhawk org The tracking hardware comprises a 24 GHz Yagi antenna from L com an RN XV Wi Fi module by Roving Networks and an Odroid U3 computer by Hardkernel Co ADRIEN PERKINS is a Ph D candidate in the GPS Research Laboratory at Stanford University where he received his MSc in aeronautics and astronautics LOUIS DRESSEL is a Ph D candidate in the Aeronautics and Astronautics Department at Stanford where he works on a joint project with the Stanford Intelligent Systems Lab and the GPS Research Laboratory SHERMAN LO is a senior research engineer at the Stanford University GPS Laboratory PER ENGE is a professor of aeronautics and astronautics at Stanford where he directs the GPS Research Laboratory This article is based on a technical paper presented at the 2015 ION GNSS conference in Tampa Florida 56 GPS WORLD WWW GPSWORLD COM FEBRUARY 2016
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