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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。
Stepping frequency signal (SFWs) can obtain high range-resolution without increasing the instantaneous bandwidth of radar system, and also has the problem of poor anti-jamming ability and low equivalent repetition frequency. In addition, Due to the accumulation of time due to the working conditions of the radar carrier aircraft, will lead to the azimuth data is incomplete. In view of the above problems, a step-frequency synthetic aperture radar (SAR) imaging method with two-dimensional aperture and frequency sparsity is proposed. Firstly, the SAR imaging model of sparse step frequency signal (SSFWs) is analyzed, and then the distance imaging processing is completed based on the compressed sensing theory. Secondly, aiming at sparse aperture echo data, distance migration correction and azimuth compression processing are realized by constructing imaging operator and compression perception reconstruction model, and the two-dimensional imaging results are obtained. Compared with the traditional SAR imaging of the step frequency signal, the proposed method can achieve accurate SAR imaging with a small amount of frequency resources and radar echo data. Finally, the simulation and the measured step-frequency radar data are processed to verify the effectiveness and feasibility of the proposed method.