Two-dimensional Autofocus for SAR Filtered Backprojection Imagery

Filtered backprojection (FBP) algorithm is a popular choice for nonlinear trajectory SAR image formation processing. However, how to efficiently autofocus the defocused FBP imagery is still a challenging problem. In this paper, a new interpretation of the FBP derivation is presented. Then, by incorporating the a priori knowledge on the 2-D phase error, an accurate and efficient 2-D autofocus approach is proposed. The new approach possesses much higher accuracy and efficiency than conventional blind methods. Experimental results clearly demonstrate the effectiveness and robustness of the proposed method.