低信噪比长伪码直扩信号伪码周期的估计方法

针对低信噪比长伪码调制直扩(DS-SS)信号的伪码(PN码)周期参数估计的难题,提出了一类基于信号功率谱二次处理的新方法。该方法首先对信号的功率谱进行估计,接着将估计出的功率谱作为输入信号再来求取功率谱,最后得到的二次谱就会在长伪码调制DS-SS信号PN码周期的整数倍处得到一列尖锐的二次谱线,通过估计这些谱线的间距就可以获得其PN码的周期估计。为了在低信噪比情况下增强二次谱线和估计效果,采用了由多个接收信号矢量计算得到的二次谱结果进行平均累积的办法。理论分析和计算机模拟表明,该类方法在较低的输入信噪比条件下能良好地工作。

New method for periodic estimation of the PN sequence in the lower SNR long code DS-SS signals

A kind of new method based on the reprocessing of the power spectrum of the long code direct sequence spread spectrum(DS-SS) signals is proposed to solve the periodic detection and estimation of the PN sequence in long code DS-SS signals.This method estimates the power spectrum of the received signals at the first step,then looks upon the estimated power spectrum as input signals and computes its power spectrum again,finally the power spectrum reprocessing results will arise spectral line with interval equal to the period of PN sequence.In order to enhance the spectral line and achieve good estimate effect in lower signal to noise ratios,the average accumulant method to postprocess the estimated power spectrum reprocessing results is adopted The computer simulation results show that the proposed methods can work well under the lower signal to noise ratio input signals.