Focusing of Wide-Swath Range Sweep SAR With Extended Wide Nonlinear Chirp Scaling Algorithm

Multichannel, Digital beamforming (DBF)-based high-resolution wide-swath synthetic aperture radar (HRWS-SAR) is dedicated to acquiring large observation width and high resolution in a single pass. However, the existing HRWS-SAR imaging modes are difficult to cover effectively for the coastline area not parallel to the satellite orbit. Combined with the beam direction changing, variable pulse repetition interval (PRI) and distance-oriented DBF techniques, the wide-swath range sweep SAR (WRS-SAR) can image the wide coastline area not parallel to the satellite orbit at high resolution in a single pass. In this study, an extended wide nonlinear chirp scaling (E-WLNCS) algorithm is proposed, which mainly consists of a time-domain blind range sample reconstruction algorithm combined with phase variation estimation and a nonuniform resampling algorithm combined with Doppler variation correction, and the effectiveness of the proposed modified E-WLNCS algorithm is demonstrated through point target and surface target simulations.