Range-layover to height mapping in high grazing angle synthetic aperture radar for non-interferometric 3-D image formation

Abstract

Small unmanned aircraft or other aircraft that operate at short range are likely to need to operate at steep look-down angles. Imaging at high grazing angle causes range-layover which affects synthetic aperture radar (SAR) images in the down-range direction, but not in cross-range. By making a number of images at different look angles relative to the target, the 3-D position of individual scatterers on the target can be calculated, as long as they remain visible over an appreciable angular extent. The range-layover to height mapping algorithm is presented here for forming 3-D images from high grazing angle SAR data. This algorithm only requires data collected from a single antenna and a single pass of the target to form a 3-D image.