Ghosting Suppression with the Joint Sub-channel BP Image Reconstruction for Non-uniform Sampling SAR

In recent years, the back-projection (BP) algorithm has shown good potentials in SAR focusing with nonideal conditions like nonideal trajectory and nonuniform sampling. However, when applying the original BP algorithm directly to periodic non-uniform sampling data, ghostings can be introduced into the imaging results, leading to image quality distortion. To address this issue, a novel reconstruction method based on joint sub-channel BP images is proposed. We first analyze the causes and properties of Doppler grating lobes and BP ghostings in the periodic non-uniform signals. Based on the analysis, a reconstruction process of the joint sub-channel BP images is established to achieve the purpose of suppressing ghosting. The proposed method can be smoothly combined with the Ground Cartesian back-projection (GCBP) algorithm to realize high computational efficiency. Finally, the simulation and measured data are presented to verify the effectiveness of the algorithm.