基于导频辅助的DFT时变频率捕获算法

Pilot-aided DFT time-varying frequency acquisition algorithm

以线性调频信号为信号模型,围绕时变频率捕获算法展开研究。重点研究了传统的时变频率捕获算法--延迟自相关算法,然后针对延迟自相关算法无法在低信噪比下实现线性调频信号参数估计的问题,提出一种基于导频辅助的离散傅里叶变换(DFT)时变频率捕获算法。仿真结果表明,提出的算法和延迟自相关算法均基于2次快速傅里叶变换(FFT)运算实现了线性调频信号的频偏和频偏变化率的捕获,该算法具有更低的信噪比门限。

This paper studies on time-varying frequency acquisition algorithms,taking Linear Frequency Modulation(LFM)signal as signal model.Firstly,this paper focuses on Delayed Autocorrelation Algorithm,which is one of the traditional time-varying frequency acquisition algorithms.Then,a pilotaided Design For Testability(DFT)time-varying frequency acquisition algorithm is proposed,according to the problem that Delayed Autocorrelation Algorithm cannot realize the parameter estimation at low Signal to Noise Ratio(SNR).At last,the simulation results show that both the proposed algorithm and the Delayed Autocorrelation Algorithm are based on two Fast Fourier Transform(FFT)operations to estimate the frequency offset and the rate of frequency offset for LFM signal,and the proposed algorithm has a lower SNR threshold.