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Near-field synthetic aperture imaging of buried objects and fluids

This paper describes imaging of buried objects and fluids. The motivations are to locate pipe leakage and unexploded ordnance. The method is to radiate and receive continuous, discrete frequency radio waves with antennas near the ground, to synthesize sampled area arrays of reflectance data, and to process the data into images with an algorithm based on angular spectrum diffraction theory. Experimental results are presented for three setups. An initial, laboratory setup had a single, spatially scanned antenna; it was used to image buried mud. The second with an array of five antennas on a vehicle, images a buried creosote pit. The third, with a vehicular array of seven antennas, imaged buried metallic objects and depressions in the soil surface.