Imaging and Refocusing of Moving Target in Polar Format Spotlight SAR Image

The synthetic aperture radar (SAR) signatures of moving target are the basis of ground moving target detection imaging and relocation. In this article, a new interpretation of the polar format algorithm (PFA) for general SAR imaging is presented. We derive the image spectrum of the moving target. Based on the spectrum derived, the SAR signatures of moving targets are analyzed in detail, including the geometric displacement and the defocusing effect, and perform refocus processing through phase gradient autofocus(PGA). Finally, the analytical results are verified via simulation data processing.