<title>Conventional and synthetic aperture processing for airborne ground-penetrating radar</title>

Abstract

For the past four years Airborne Environmental Surveys (AES), a Division of Era Aviation, Inc. has used unique and patented airborne Frequency-Modulated, Continuous Wave (FM-CW) radars and processes for detecting and mapping subsurface phenomena.' Primaiy application has focused on the detection of man-made objects in landfills. hazardous waste sites (some of which contain unexploded ordnance). and subsurface plumes of refined free-floating hydrocathons. Recently, MSB Technologies, Inc. (MSB) has developed a form of synthetic aperture radar processing (SAR), called GPSAR, that is tailored especially for the AES radars. Used as an adjunct to more conventional airborne ground-penetraüng radar data processing techniques, GPSAR takes advantage of the radars' coherent transmission and produces imagery that is better focused and more accurate in determining an object's range and true depth: This paper describes the iterative stages of data processing and analysis used with the radars and shows the added advantages that GPSAR processing offers.