一种提高距离分辨率的FMCW SAR RD成像算法

A RD Imaging Method for Improving Range Resolution of FMCW SAR

摘要:

调频连续波合成孔径雷达(FMCW SAR)是一种新近提出来的成像雷达体制,它结合调频连续波与合成孔径成像技术,具有体积小、重量轻、成本低、分辨率高等一系列优点。从频谱的角度进行分析,FMCW SAR的距离分辨率取决于频率测量分辨率。文章研究了一种FMCW SAR高距离分辨率成像算法——利用FFT得到差频信号谱峰的粗略范围,再对这一范围进行Chirp Z变换,从而实现距离高精度估计,并且避免了大的计算量。仿真结果表明该方法的有效性。

Abstract:

The frequency modulated continuous wave synthetic aperture radar (FMCW SAR) is a newly proposed radar imaging system, which combining FMCW technique with synthetic aperture imaging methods has the advantages such as small cubage, light weight, cost-effective, high-resolution, etc. FMCW SAR range resolution is depended on frequency measuring accuracy from spectrum aspect. In this paper, a high range resolution FMCW SAR imaging algorithm was researched. The method was getting the approximate range of frequency peak of FMCW SAR beat frequency signal, using FFT, and then subdividing frequency in this range, by Chirp-Z transform. Thus we could get the high precision range estimation; furthermore, the large calculation amount was avoided. The simulation results showed that the method was valid.