SAR moving target imaging using semi-blind two-dimensional autofocus algorithm

摘要

Due to uncertainty on target's motion, synthetic aperture radar (SAR) processing can't compensate for the two-dimensional (2-D) phase error of moving targets completely. Therefore, moving targets SAR images often appear 2-D defocused. In this paper, we propose a 2-D autofocus method for refocusing the defocused moving targets SAR images. The new method only requires a direct APE estimation, while the residual 2-D phase error is computed directly from the estimated APE by exploiting the analytical relationship between the 2-D phase error and APE. The simulation experiment proves the proposed approach offers obvious advantages in both computational efficiency and estimation accuracy.