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 airto-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.