CONTINUOUS GEOREFERENCING FOR VIDEOBASED REMOTE SENSING ON AGRICULTURAL AIRCRAFT

Abstract

An imagebased remote sensing system was configured on an agricultural spray plane. The system uses a videomapping system (VMS) for continuous georeferencing of images obtained by digital video. Three differential GlobalPositioning System (GPS) configurations and one nondifferential system, dedicated to the imaging system, were evaluatedin parallel with the planes GPS to judge useable accuracy of a GPS/VMS combination when flying at altitudes of 21 to 420 m(70 to 1400 ft). Positioning accuracy was determined by comparing data from the GPS and video mapping system on theairplane to precise GPS data on the ground. One differential GPS configuration and the nondifferential GPS performed bestand had fewest problems updating a position fix. Over four field sections flown, differences in position ranged from 66 to+39 m (216 to +128 ft) using the differential GPS and from 11 to +83 m (36 to +272 ft) using the nondifferential GPSin separate tests. Differential correction was not necessary for reasonable accuracy within system limitations, but accuracywas frequently influenced by user subjectivity when locating points using the video mapping software. The system should findits greatest utility where field areas cannot be georeferenced using landmarks or other reference points, as would be the casefor lowaltitude remote sensing over large field areas.