高分辨率机载合成孔径雷达实时成像对自聚焦的要求非常高。自聚焦除了要有足够高的精度和高计算效率外。还要求能够适应信杂比较低的情况。文中对频移相关算法进行了改进，大大降低了自聚焦对信杂比的要求，增强了算法的鲁棒性。

The demand of autofocus for high resolution real time synthetic aperture radar(SAR) is very high.The autofocus algorithm not only need enough precision and computational efficiency,but also need fitting low signal to clutter rate(SCR).A modified Shift-And-Correlate(SAC) autofocus algorithm is presented,which decrease the demand of SCR and the algorithm is more robust.

TN958 TN957.52