星载聚束SAR频域极坐标算法研究

A Study on Frequency Domain Polar Format Algorithm of Spaceborne Spotlight SAR

介绍了一种与经典时域极坐标成像算法基本思路及实现步骤类似的频域极坐标算法。首先说明了频域极坐标算法原理及实现步骤。然后分析了时域极坐标算法存在残余视频相位误差的原因及其对成像结果的影响。经推导得出频域极坐标算法从根本上避免了该误差。又对两算法带宽进行研究,指出在高精度的星载聚束SAR成像时,频域极坐标算法不存在时域极坐标算法的距离带宽展宽效应。最后利用星载聚束SAR参数进行仿真,证实了该算法较时域极坐标算法的优势。

This paper introduces a frequency domain polar format algorithm, which is similar to the time domain polar format algorithm in basic principle and implementation approach. Firstl, theory and procedure of the frequency domain polar format algorithm are described. Then, the origin and the effect on imaging of time domain polar format algorithm residual video phase error are analyzed. From analysis the paper comes to the conclusion that frequency domain polar format algorithm can avoid the error completely. Both algorithm bandwidth are studied and the fact that frequency domain polar format algorithm has no range bandwidth expanding effect in high precision spaceborne spotlight SAR imaging is pointed out. Finally, some simulations using spaceborne spotlight SAR parameters testified the advantages of frequency domain polar format algorithm.