高分辨宽测绘带星载合成孔径雷达频域重构算法

Frequency-domain spectrum reconstruction algorithm for high-resolution and wide-swath space-borne synthetic aperture radar

针对传统星载合成孔径雷达(SAR)系统高分辨率和宽测绘带之间的矛盾,采用方位向偏置相位中心结合距离向波束扫描(ScanSAR)模式实现同时高分辨宽测绘带SAR成像,并针对雷达脉冲发射频率、平台速度和天线尺寸不满足严格约束条件导致的方位向非均匀采样提出了频域重构算法。该算法可以实现精确频谱重构,并且极大地提高了系统设计和参数选择的灵活性。五扫六通道SAR系统的频域重构算法的仿真结果显示成对回波抑制达60 dB以上,方位模糊比达-23 dB,证明了该算法的有效性。

The confliction between swath width and resolution in the routine space-borne synthetic aperture radar （SAR） can be solved by displaced phase centers multi-beam in azimuth （DPCA） with ScanSAR in across-track direction. However, the pulse repetition frequency, sensor velocity and antenna size underlie a stringent timing requirement and any deviation will result in a non-uniform sampling in space domain. The paper derives an innovative frequency-domain reconstruction algorithm, which ena bles a recovery of the unambiguous Doppler spectrum also in case of a non-uniform sampling. This algorithm is not iterative and precise, and can improve greatly the flexibility of system and parameters choice. The simulation results which illustrate the algo rithm＇s validity show that the spurious image from the non-uniform sampling is suppressed to below -60 dB and the azimuth ambiguity-to-signal ratio （AASR） is below -23 dB.