基于双通道DFRFT互谱法的Chirp信号时延估计

Time Delay Estimation of Chirp Signals Based on Double-Channel DFRFT Cross-Spectrum

针对脉冲Chirp类信号的时延估计问题,理论推导了基于离散分数阶Fourier变换的脉冲Chirp信号的特性,分析了当时延参量等效的分数阶Fourier域的频率大于采样率时,脉冲Chirp信号的分数阶Fourier域谱产生混叠,造成时延估计模糊的问题,并提出基于离散分数阶Fourier变换(DFRFT)双通道互谱法进行时延估计,给出两个通道采样率选取的原则及算法的性能分析,实验结果表明,在一定的采样率下,算法能够快速精确地估计脉冲Chirp信号的时延参数.

For the problem of time-delay estimation for Chirp pulse signals ,the characteristics of Chirp pulse signals based on the discrete fractional Fourier transform was theoretically derived .When time-delay equivalent frequency parameter was greater than the sampling rate in fractional Fourier domain ,the spectrum of Chirp pulse signals in fractional Fourier domain produced aliasing , which caused the delay estimation ambiguity problem .In order to solve this problem ,the time-delay estimation of Chirp signal based on double-channel DFRFT cross-spectral method was proposed ,then the principles of the two-channel sampling rate selection and the performance analysis was given .The experimental results show that ,in a certain sampling rate ,the proposed algorithm is able to quickly and accurately estimate the time-delay parameters of Chirp pulse signals .