一种提高DSSS信号载波频率估计精度的算法

An Algorithm for Improving DSSS Signal Carrier Wave Frequent Measurement Precision

针对快速傅里叶变换（fast Fourier transform,FFT）算法频率估计误差较大的问题,采用离散时间傅里叶变换（discrete time Fourier transform,DTFT）辅助FFT估计频率谱峰值,以提高直接序列扩频（direct sequence spreadspectrum,DSSS）信号多普勒测量精度的算法。该算法利用FFT估计频谱最高峰值及次高峰,在对应频点之间平均取10个频率点做DTFT,求幅值的极大值点,以确定频率谱峰值精确位置。仿真实验结果表明,该算法可有效提高捕获过程中DSSS信号频率的测量精度。

In terms of the large frequency-evaluating error using FFT algorithm, a kind of algorithm to enhance Doppler measurement precision of DSSS signal by using FFT evaluating peak value of frequency spectrum with assistance of DTFT is presented in this paper. Firstly, this algorithm evaluates the peak value and hypo-peak value of frequency spectrum via FFT. In order to get max-peak value and make sure the accurate position of frequency spectrum＇s peak value, this algorithm then performs DTFT using ten frequency values taken between their corresponding frequency values averagely. The simulation results demonstrate that it can enhance the precision of frequency in acquiring DSSS signal effectively.