一种提高FMCW SAR距离分辨率的补偿方法

摘要

Frequency Modulated Continuous Wave (FMCW) Synthetic Aperture Radar (SAR) is a small-size, light-weight and cost-effective imaging radar, which is suitable for operation on a small flight platform. In the dechirp processing of FMCW SAR, the transmitting signal is more feasible for using as the mixing signal. But the bandwidth is decreased because of echo delay in the dechirp processing. The bandwidth decrease becomes serious when the target is far away or the pulse repetition time is short, and the range resolution is reduced. We constructed a unified compensation function to compensate for the echo signal, thus the bandwidth was fully exploited and the range resolution was unaffected by echo delay. Simulation results prove the correctness of the compensation function and the effectiveness of the compensation method.%调频连续波(FMCW)合成孔径雷达(SAR)具有体积小、重量轻、耗电少、造价低等优点,非常适合搭载于小型平台.在FMCW SAR的去调频处理中,选择发射信号作为混频信号更具现实可行性,但混频中会因回波的时延导致损失部分带宽,在目标距离较远或系统脉冲重复时间较短时,带宽损失尤为严重,降低了距离分辨率.提出通过构造统一的补偿函数对回波信号进行补偿,使带宽得到充分的利用,保证距离分辨率不受回波时延的影响.最后通过仿真验证了补偿函数的正确性和补偿方法的有效性.