Two-dimensional Autofocus Approach for bistatic SAR Polar Format Algorithm

The existing two-dimension (2-D) autofocus algorithms for bistatic system aperture radar (SAR) do not make full use of the structure of phase error knowledge and estimate phase error in a blind manner. They often suffer from low computational efficiency and imprecise parameter. In this paper, an efficient 2-D autofocus algorithm for bistatic SAR is presented. First, the new bistatic PFA (polar format algorithm) interpretation is used to derive the structure of phase error. Then, based on this knowledge, a 2-D autofocus approach is proposed. This algorithm only requires an estimate of azimuth (1-D) phase error, and then the 2-D phase error can be computed from the 1-D phase error. Compared with other existing autofocus approaches, the experimental results demonstrate that both the accuracy of the parameter estimation and the computational efficiency in this algorithm is obviously improved.