An Advanced Azimuth Ambiguity Suppression Scheme for Azimuth Multichannel SAR System

Azimuth ambiguity in synthetic aperture radar (SAR) images results from the limited azimuth sampling rate and seriously affects image quality and normal applications. Multiple algorithms for azimuth ambiguity elimination have been proposed. However, most algorithms adopt a single-channel model and ignore the effect of additional reconstruction operations on ambiguity in azimuth multichannel systems (MCSs). In this letter, the particularity of azimuth ambiguity for MCSs is analyzed theoretically. A refined ambiguity suppression scheme based on multichannel cancellation (MCC) and ambiguity refocusing is proposed. The ambiguity region is first located through the comparison of multi-look image pairs. Then the interference image for ambiguity extraction is cancellated through MCC. Consequently, the ambiguous image is refocused and extracted. Finally, the ambiguity is reversed to the echo domain to handle the special replicated ambiguity problem for MCSs. With the proposed scheme, ambiguity suppression performance has improved for MCSs. The validity of the proposed algorithm is further verified through LuTan-1 real data.