摘要
在欠采样测量基础上,提出了一种基于盲压缩感知(BCS)的线性调频(LFM)宽带雷达信号欠采样与重构新框架。这一机制利用LFM雷达信号在分数阶傅里叶变换(FRFT)域上良好的能量聚集特性,将LFM及其延迟信号看做是未知p阶次FRFT域上的稀疏线性组合。首先通过时延相关解线调欠采样得到最佳稀疏FRFT域,再以此构造出原信号对应的p阶次离散FRFT(DFRFT)稀疏基字典,最后结合离散FRFT系数的块稀疏性利用块重构算法从测量值中估计出稀疏系数,同时论证了LFM信号单通道BCS问题解的唯一性,从而实现了稀疏基未知情况下针对LFM宽带雷达信号的盲压缩感知,为非合作条件下LFM信号欠采样采集与无源探测提供了一种新思路。
A novel framework of sub-Nyquist sampling and reconstruction for linear frequency modulation （LFM） radar signals based on the theory of blind compressed sensing （BOS） is proposed. This mechanism takes LFM signals as a sparse linear combination under an unknown order p of fractional Fourier transform （FRFT） domain. Firstly, we make use of the scheme of delays correction dechirp and good energy concentration of LFM signal in proper FRFT domain to determine the optimal order, which meets the convergence conditions. Secondly, we construct discrete FRFT （DFRFT） basis dictionary according to the specific sparse FRFT domain dominated by p. To reconstruct the sources, group sparse reconstruction al- gorithms are chosen with less data storage and lower computational complexity. Finally, the results are provided to verify the uniqueness of the proposed framework, realizing the undersampling and reconstruction without the knowledge of priori sparse basis for LFM radar signals under the theory of BCS. The novel framework can bring a new solution concerned about the under-sampling and detection for LFM signals under the environment of non-collaboration.
出处
《航空学报》
EI
CAS
CSCD
北大核心
2014年第8期2261-2270,共10页
Acta Aeronautica et Astronautica Sinica
基金
国家"863"计划(2013AA7014061)~~
关键词
压缩感知
线性调频信号
分数阶傅里叶变换
欠采样
盲压缩感知
compressed sensing
linear frequency modulated
fractional Fourier transform
under-sampling
blind compressed sensing
