Improved two dimensional autofocus of SAR imaging

With the resolution of SAR getting finer, the traditional 1-D autofocus algorithm may fail to cope with the situation that a target´s echo exhibits a residual range migration error exceeding one or more range resolution cells during the course of the synthetic aperture. In this case 2-D autofocus becomes particularly important. Commonly used 2-D autofocus algorithm is based on range correlation and PGA, and is of high computational complexity. In this paper we propose an improved 2-D autofocus algorithm of SAR imaging, in which a subset of adjacent range resolution cells containing the prominent scatterers are selected and process by mean location method. Experiments on simulated data and real data show the effectiveness of improved method.