一种用于条带式RD算法的组合实时PGA方法
doi: 10.3724/SP.J.1146.2005.01283
A Combined Real Time PGA Method for Strip Map Airborne SAR with RD Algorithm
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摘要: 随着合成孔径雷达(SAR)分辨率的提高，方位向相位误差的影响逐渐增大，传统的相位梯度自聚焦(PGA)方法虽然可以估计出高次误差，但是通常都需要迭代，给实时成像造成了很大困难。该文结合条带式RD算法和PGA自聚焦算法的特点，提出了一种组合的实时PGA方法。这种方法将频移相关距离门算法(SACGS)算法与PGA算法结合，不仅大大降低了计算量，可以不用迭代而达到良好的效果，而且降低了对运动初始参数的精度要求。仿真和实际数据均验证了这种方法的有效性。Abstract: In the high resolution SAR, the effect of motion error at the azimuth direction is more severe. Though the traditional Phase Gradient Autofocus(PGA) algorithm can be used to estimate the motion error, the iterative phase correction has to be done. The huge computation makes it difficult to be used in real time image processing. In order to meet the request of real time imaging of high resolution SAR, the Shift And Correlate (SAC) algorithm, Shift And Correlate of Gate Strategy (SACGS) algorithm, PGA algorithm and Range Doppler (RD) algorithm are combined in this paper. With the new combined algorithm, the iterative operation can be reduced or even omitted. At the same time, the computation and the precision request for the initial motion parameter is decreased. The simulation and the result of imaging for real SAR data can validate the new algorithm.
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