TOPS Mode Raw Data Generation From Wide-Beam SAR Imaging Modes

A synthetic aperture radar (SAR) raw data simulator of distributed target scenes is an important tool for testing the system parameters, imaging algorithms, and so on, particularly for these recently proposed novel imaging modes. The Terrain Observation by Progressive Scans (TOPS) mode achieves the wide-swath imaging coverage and overcomes major drawbacks in ScanSAR by electronically steering the azimuth beam along track during the whole acquisition time. In this letter, a novel TOPS mode raw data generation approach from conventional wide-beam SAR imaging modes is proposed, by invoking the fact that the TOPS raw data can be considered as a part of the stripmap/spotlight raw data with the exploited wide azimuth beam interval. In this approach, an azimuth-varying filter is introduced to obtain the desired TOPS raw data and set others to zero. Moreover, the conventional stripmap and spotlight mode raw data can be efficiently generated in the 2-D Fourier transformed domain. Therefore, a fast raw data simulator can be easily achieved by taking this approach. Simulation results validate the proposed simulation approach.