FRFT域LFM雷达回波信号的压缩采样模型

针对宽带雷达线性调频信号(Linear Frequency Modulated,LFM)带宽大、采样率高、存储容量要求高的问题,设计了一种基于压缩感知的 LFM雷达回波信号的欠采样整体方案。首先,利用 LFM信号在分数阶傅里叶变换(FRactional Fourier Transform,FRFT)域上良好的能量聚集特点,提出了一种基于DFRFT核矩阵的正交基字典构造方法,在此基字典的基础上利用随机解调器和匹配追踪类算法构建了一个 LFM雷达回波信号的压缩采样和重构系统模型。仿真结果验证了 FRFT域处理 LFM雷达回波信号的可行性和有效性,LFM雷达信号在该正交基字典上的稀疏表示效果要优于现有的波形匹配字典,而且具有更好的抗噪性能和自适应性能。

Compressive sensing of linear frequency modulated echo signals in fractional Fourier domains

For the large bandwidth, high sampling rate, high storage capacity in linear frequency modulated(LFM) signals applied in wideband radar, this paper designs an overall solution for undersampling the radar echo of LFM signals based on compressive sensing(CS). First, by use of the good energy characteristics of LFM signals in the fractional Fourier transform(FRFT) domain, a novel orthogonal base dictionary based on the DFRFT nuclear matrix is proposed. Combining this dictionary with random demodulation and matching pursuit algorithms, an LFM radar echo signal sampling and reconstruction system model is built. Simulation results verify the feasibility and effectiveness of this scheme, and sparse representation of the LFM radar echo in the orthogonal basis dictionary is superior to the existing waveform matching dictionary, and has better anti-noise and adaptive performance.