一种孔径和频率二维稀疏的步进频SAR成像方法

 步进频率信号(SFWs)在不增加雷达系统瞬时带宽的情况下能够获得高的距离向分辨率的同时,也存在着抗干扰能力较差及其等效重复频率较低的问题,并且在方位向积累时间内由于雷达载机工作状态的变化,会导致方位向的数据录取不完整。针对上述问题,提出一种孔径和频率二维稀疏的步进频合成孔径雷达(SAR)成像方法。首先,分析了稀疏步进频率信号(SSFWs)的SAR成像模型,然后基于压缩感知理论完成距离向成像处理。其次,针对稀疏孔径的回波数据,通过构造成像算子和压缩感知重建模型的方法实现其距离徙动校正和方位压缩处理,进而获得二维成像结果。相比于传统的步进频率信号SAR成像,利用所提方法能够在少量的频率资源和雷达回波数据情况下实现准确的SAR成像。最后,通过对仿真和实测的步进频率雷达数据进行成像处理,验证了所提方法的有效性和可行性。

A SAR imaging method with sparse aperture and frequency using stepped-frequeney waveform

Stepped-frequency waveforms (SFWs) can use the digital signal processing to obtain high range resolution with relatively narrow instantaneous bandwidth, but they also have the disadvantages of poor anti-jamming capability and long-time period of transmission. And in the coherent integration time, it frequently occurs that some of echo data are missing. In this paper, a novel synthetic aperture radar (SAR) imaging method with sparse aperture and frequency is proposed based on sparse stepped-frequency waveforms (SSFWs). Firstly, the signal model for SSFWs SAR imaging is analyzed and then the range compression is achieved by using the compressed sensing theory. Secondly, as to the sparse aperture data, the imaging operator and the CS-based imaging scheme are constructed to implement the range cell migration correction and azimuth compression simultaneously. Compared with the traditional SAR imaging method of SFWs, much smaller number of frequencies and smaller amount of imaging data are required for SAR imaging by using the proposed method. Finally, the effectiveness of the proposed method is proved by the simulation and experimental results.