基于周期WHT循环滤波的交叠类似LFMCW信号检测与分离
收稿日期: 2012-11-27
修回日期: 2013-07-11
网络出版日期: 2013-08-08
基金资助
国家自然科学基金（61102167，60972159）;航空科学基金（20085184003）
Detection and Separation of Overlapped Quasi-LFMCW Signals Based on Periodic WHT Recurrent Filter
Received date: 2012-11-27
Revised date: 2013-07-11
Online published: 2013-08-08
Supported by
National Natural Science Foundation of China (61102167, 60972159);Aeronautical Science Foundation of China (20085184003)
针对非协作方式下交叠类似线性调频连续波（LFMCW）信号的检测与分离问题，以LFMCW信号为例推导了一种基于周期WHT（Wigner-Hough Transform）循环滤波的检测与分离算法，并根据该类信号与LFMCW信号的联系与区别，将其推广应用于类似LFMCW信号的检测与分离。该算法能在较低信噪比条件下实现交叠类似LFMCW信号的分离，且分离后的信号具有抑制噪声的作用;同时针对强信号分离时带来的强信号残留和弱信号损失的问题，设计了一种基于单元平均的窄带频域陷波滤波器，在充分考虑滤除强信号能量的同时，实现了弱信号能量的更好保留。仿真结果表明：当虚警概率为0.01，输入信噪比大于－16 dB时，算法的检测概率大于0.9，相比同条件下的WHT和分数阶Fourier变换（FrFT）分别提高了7 dB和6 dB;对交叠类似LFMCW信号，当最弱信号信噪比大于－7 dB时，就可使分离的相关系数达到0.9以上。
张立民 , 钟兆根 , 王泽众 , 王建雄 . 基于周期WHT循环滤波的交叠类似LFMCW信号检测与分离[J]. 航空学报, 2013 , 34(11) : 2580 -2589 . DOI: 10.7527/S1000-6893.2013.0352
For weak signal detection and separation of overlapped quasi-LFMCW signals with non-cooperative mode, a new algorithm based on periodic WHT recurrent filter is proposed by using LFMCW signal as an example. Then extend the use of the proposed algorithm to quasi-LFMCW signals with the relationship and difference between them. The proposed algorithm can realize the separation of overlapped quasi-LFMCW signals at low signal-to-noise ratio (SNR), also the separated signals can effectively suppress noise. Aimed at solving the core problem of the high energy signal's strong remainder and the weak energy signal's energy loss after the high energy signal's separation, a narrow frequency excision filter based on cell average is designed, which could not only sufficiently filter the high energy signal, but also keep the weak signal as completely as possible. Simulation results indicate that when false alarm probability is set to 0.01 and SNR is greater than -16 dB, the probability of detection reaches above 0.9. With respect to WHT and FrFT under the same condition, the detection performance is improved by 7 dB and 6 dB respectively. In addition, for overlapped quasi-LFMCW signals, when the weakest signal's SNR is greater than -7 dB, the correlation coefficients between separated and original signal component both exceed 0. 9.
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