An autofocusing imaging algorithm for wall penetrating SAR

The absence of wall´s characteristic will smear and blur the image, shift the target position, and even defocus the imaging result. To solve the problems, a novel autofocusing imaging algorithm is proposed in this paper. Firstly, the electromagnetic field is employed as a 2-D matching filter during the imaging processing. Then, the electromagnetic field in the air-to-wall medium is replaced by that in the air-to-air medium. Thirdly, the mismatching error, which is proved to be an extra frequency gap at the shifted depth, is compensated by using the phase cross-correlation method. Finally, the correctness and efficiency of the proposed method are verified by the full wave simulation with data from CST.