A TOPSAR Processing Algorithm Based on Extended Chirp Scaling: Evaluation with TerraSAR-X Data

Abstract

This paper presents an efficient phase preserving processor for the 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. The TOPS signal includes particularities of both ScanSAR and Spotlights modes, but existing processing algorithms do not provide an efficient processing of TOPS data. This paper presents an algorithm based on Extended Chirp Scaling (ECS) together with a new azimuth scaling step. The proposed solution allows also the selection of the final azimuth image sampling without the need of interpolations, hence easing the forthcoming mosaicking of the different subswaths. Real data acquired by TerraSAR-X are used to validate the processor.