Wide Swath SAR Techniques

For the conventional single-channel Synthetic Aperture Radar, there is a conflict between azimuth resolution and swath coverage because of minimum antenna area constraint. With the same azimuth resolution, multi-channel SAR can achieve much wider swath than single-channel SAR. Multi-channel mode of SAR is investigated in this paper.Firstly, this paper offers the basic principle of SAR imaging and establishes the echo model. Based of the Chirp Scaling imaging algorithm, a detailed study is processed in MATLAB. Then, the conflict between azimuth resolution and swath coverage is introduced through math deduction. In order to deal with the conflict, multi-channel mode is applied. Multi-channel in the azimuth direction SAR includes single phase center multibeam in the azimuth direction (SPCA) SAR and displaced phase center multibeam in the azimuth direction (DPCA) SAR. The two formations can improve one characteristic and not affect the other one and solve range-Doppler ambiguities. The basic principles of SPCA and DPCA mode are discussed and several simulations are performed to verify the algorithm. However, DPCMA will lead to non-uniform sampling in azimuth and can’t directly use the traditional imaging algorithms to process the echo data, otherwise false targets will turn up. To solve this problem, multi-channel reconstruction filters are used. At last, the two wide-swath algorithms are simulated by MATLAB and compared in the paper. With the same azimuth resolution, the swath width of DPCA is wider than SPCA system.