Efficient TOPS mode raw data simulator of extended scenes

Abstract

The terrain observation by progressive scans (TOPS) mode is a novel wide-swath imaging scheme, and it reduces the major drawbacks existing in conventional ScanSAR. An accurate and efficient synthetic aperture radar (SAR) raw data generator of distributed extended scenes is of considerable value for testing system parameters and verifying the imaging algorithms, particularly when the real raw data of recently proposed imaging mode are not available yet. The TOPS mode raw data simulation can only be exactly and directly realised in the time domain because an azimuth window function is not be suitable for each point target echo in the scene, however it is not efficient especially when simulating an extended scene. In this study, a novel TOPS mode raw data simulation method is presented to solve above issues. In this approach, an azimuth linear frequency modulated signal is introduced to form the azimuth window function and the echo is obtained in two-dimensional frequency domain by chirp-z transformation, which improves the efficiency greatly while retaining the simulation accuracy. Simulation results for point targets and a real SAR image demonstrate its validity and effectiveness.