基于周期FRFT的交叠类似LFMCW信号的循环检测与分离

Recurrent Detection and Separation of Overlapped Quasi-LFMCW Signals Based on Periodic FRFT

针对多分量交叠类似线性调频连续波(LFMCW)信号的检测与分离问题,提出了一种基于周期分数阶傅里叶变换(periodic FRFT)的循环检测与分离算法。介绍了锯齿LFMCW、对称三角线性调频连续波(STLFMCW)和具有类似线性调频特征的多相编码连续波信号的特点,分析了周期FRFT对此类信号处理的优势;推导了基于周期FRFT的交叠LFMCW信号的检测与分离原理,通过解线调将信号的分离转化为频域的窄带滤波问题,并将该算法推广应用于交叠类似LFMCW信号的检测与分离。仿真结果表明:该算法能够在较低信噪比条件下实现交叠类似LFMCW信号的检测与分离,且分离后的信号具有抑制噪声的作用。

For weak signal detection and separation of multi-componentsignals,tional Fthis paper proposes a recurrent detection and separation methodoverlapped quasi-LFMCWbased on the periodic frac-ourier transform （FRFT）. It first describes the signal characteristics of LFMCW, STLFMCWand polyphase code continuous waves with similar chirp characteristics, and introduces the process-ing advantage of periodic FRFT for these signals. It also derives the theory of detection and separa-tion method of overlapped LFMCW based on the periodic FRFT, and converts the signal separationto a narrowband filtering problem in the frequency domain by dechirp. Finally the algorithm is ex-tended to the detection and separation of overlapped quasi-LFMCW signals. Simulation results indi-cate that the algorithm enables the detection and separation of overlapped quasi-LFMCW signals inlower SNR, and the separated signals can effectively suppress noise.