环扫SAR的快速聚焦成像算法

Fast focused imaging algorithm for circular scanning SAR

针对环扫合成孔径雷达的成像方法进行研究,分析了环扫合成孔径雷达的工作原理以及信号模型,并提出一种基于频谱分析的聚焦成像算法,该算法较好地校正了批处理数据内的距离徙动,适合对环扫SAR(Synthetic Aperture Radar)进行高精度成像处理.给出了块数据快速聚焦算法的流程图以及简单的推导过程,并在此基础上给出了环扫SAR成像处理的完整流程.较之经典多普勒波束锐化DBS(Doppler Beam Sharpening)非聚焦算法,这种聚焦算法计算量略大,但成像精度高;较之ECS(Extended Chirp Scaling)算法,虽然补偿精度稍低,但计算量大大降低.因此这种算法能够很好地用于环扫SAR高分辨率快速成像.计算机仿真结果验证本文算法的有效性.

Image formation for circular scanning synthetic aperture radar （CS-SAR） was investigated. The work principle and echo signal model of CS-SAR were described. A focused image algorithm based on spectrum analysis was presented. This focused algorithm was able to correct the range cell migration within each burst echo of CS-SAR, so it was suitable to form high precision image for CS-SAR. The algorithm flow chart and the deducing process of the algorithm for burst data were given, and the whole process flow chart for CS-SAR based on this algorithm was given also. Compared to classic unfocused Doppler beam sharpening （DBS） algorithm, this algorithm has a little more computational loads but much more imaging precision, compared to extended chirp scaling （ECS） algorithm, it has less precision but much less computational loads. It is competent for fast focused imaging for CS-SAR. The computer simulation results validates that this focused algorithm can be used to image accurately for CS-SAR.