Abstract:

Circular synthetic aperture radar (CSAR) can maintain persistent surveillance of an area of interest for a long time, and CSAR can get high resolution images from different azimuthal directions. Operating with long synthetic aperture time and wide beam, CSAR produces complicated range- and azimuth-variant phase errors. Therefore most traditional motion compensation techniques are invalidated. The effect on radar’s 3-D motion error to the echo envelop and phase is analyzed, and the Chirp-Z transform is introduced to compensate the variant amplitude error. Then a range- and azimuth-dependent motion compensation algorithm for CSAR imaging is presented. Simulation results validate the feasibility and effectiveness of the proposed approach.