A SAR Processing Algorithm for TOPS Imaging Mode Based on Extended Chirp Scaling

This paper presents an efficient phase preserving processor for TOPS (Terrain Observation by Progressive Scans) imaging mode. TOPS has been proposed as a new wide swath imaging mode, which solves the problems of scalloping and azimuth-varying ambiguities introduced by the conventional ScanSAR mode by means of steering the antenna along the azimuth direction. An algorithm based on ECS (Extended Chirp Scaling) is proposed, which uses sub-apertures and a new azimuth scaling step. The proposed solution is also efficient in the sense that it allows selecting the final azimuth image spacing by means of azimuth scaling, hence easing the forthcoming mosaicking of the different subswaths. Simulations with point targets are used to validate the processor