Azimuth Ambiguity Suppression for SAR via Variable PRF and Complex Image Deconvolution

The azimuth ambiguity phenomenon has widely existed in synthetic aperture radar (SAR). The false targets introduced by the ambiguity phenomenon may seriously affect the interpretation of SAR images. It is difficult for existing methods to suppress the azimuth ambiguity effectively at low oversampling rates. In this letter, we propose an approach of azimuth ambiguity suppression for SAR. The transmitted pulse sequence is changed to a nonuniform sampling pattern with multiple pulse repetition frequency (PRF) cycling. By taking the structural similarity of the ambiguity features as reference information, the Richardson-Lucy (RL) algorithm is utilized to suppress the ambiguity of SAR images through complex image deconvolution. The proposed method only requires simple changes to the transmitted pulse sequence and can be implemented without changing the hardware of existing SAR systems. It offers the capability to suppress the azimuth ambiguity of SAR at low oversampling rates. Experiments on real measured SAR data have verified the feasibility of the proposed method.