Extending the phase gradient autofocus algorithm for low-altitude stripmap mode SAR

Abstract

The phase gradient autofocus (PGA) algorithm has been widely used in spotlight synthetic aperture radar (SAR) to remove motion-induced blurs in the images. The PGA algorithm has been proven to be a superior autofocus method. This algorithm is extended for application to low-altitude stripmap mode SAR. Standard PGA algorithms are formulated only for spotlight-mode SAR. We describe a new algorithm which allows PGA to be applied to stripmap-mode SAR. Three SAR images with different characteristics are used in demonstrating this algorithm.