Portable device to assess dynamic accuracy of global positioning system (GPS) receivers used in agricultural aircraft.

Abstract

A device was designed to test the dynamic accuracy of Global Positioning System (GPS) receivers used in agricultural aircraft and other aerial vehicles. The system works by directing a sun-reflected light beam from the ground to the aircraft using mirrors. A photo detector points downward from the aircraft to detect the light beam, and photo detection circuitry triggers an event in the guidance system data file at the aircraft’s location corresponding to the precisely georeferenced position on the ground. Construction details are presented on the mirror-based light reflection system and photo-electronic circuitry designed to trigger an event in the guidance system’s log file. An example application evaluated the horizontal accuracy of a stand-alone GPS receiver by matching dynamic data with data from the aircraft’s guidance system. Results indicated a 2.16 s lead in position registered by the stand-alone receiver over that registered by the aircraft’s guidance system GPS receiver, which had been previously evaluated to be within 0.13 s of Real-Time Kinematic (RTK)-referenced time and position. Keywords: GPS receiver accuracy, agricultural aircraft, aerial application, remote sensing, georeferencing, UAV DOI: 10.3965/j.ijabe.20140702.008 Citation: Thomson S J, Huang Y B, Smith L A. Portable device to assess dynamic accuracy of global positioning system (GPS) receivers used in agricultural aircraft. Int J Agric & Biol Eng, 2014; 7(2): 68－74.