Response of polar format algorithm to moving target with consideration of wavefront curvature

The synthetic aperture radar (SAR) signatures of moving target are the basis of ground moving target detection and imaging (GMTI&Im). However, previous studies are mainly focused on the influence of target's motion on phase history; and little work has been done to investigate the signatures of moving target after the application of a particular SAR image formation algorithm. In this paper, we derive the image spectrum of moving target after polar format algorithm (PFA) processing. Based on this image spectrum, detailed analysis on the SAR signatures of moving target, including the geometric displacement, residual range migration, range and azimuth defocusing are performed. Simulation results validate the theoretical analysis.