Range Ambiguity Suppression for Multi-channel SAR System Using Azimuth Phase Coding Technique

For Synthetic Aperture Radar (SAR), the range ambiguity is one of the important factors causing significant deterioration of the imaging performance. Azimuth Phase Coding (APC) technique is an effective method to suppress the range ambiguity. However, since the suppression performance heavily depends on the system over-sampling rate, the APC technique could not have the same suppression performance for a multi-channel SAR system compared with a single-channel SAR system. This paper presents a novel method to suppress the range ambiguity for multi-channel SAR system based on the APC technique. First, the range ambiguity can be shifted in the azimuth frequency domain by using the APC technique, then by taking advantages of more phase centers of multiple channels, the Digital BeamForming (DBF) method can be used to filter out the range ambiguity and reconstruct the useful signal, thus most of the ambiguity components can be suppressed significantly. Finally, the simulation results validate the effectiveness of the proposed method.