Improved cross-range resolution in TOPSAR imaging using Sentinel-1A in bistatic operation

Wide-swath SAR imaging modes such as ScanSAR or TOPSAR offer synoptic observations of large-scale phenomena with a high revisit frequency at the expense of a degraded cross-range resolution. In the bistatic configuration using a SAR satellite as illuminator of opportunity and a ground-based stationary receiver close to the imaged area, this poor cross-range resolution can be improved in some favourable geometries by exploiting the sidelobe emissions of the beams illuminating the adjacent sub-swaths. This has been already demonstrated for ScanSAR mode while this paper analyzes in detail the TOPSAR mode based on measurements of ESA´s recently launched satellite Sentinel-1A.