基于重采样技术的短码直扩信号伪码估计

摘要

In order to overcome the difficulty of sampling decision in pseudo code estimation based on non inte-ger multiple symbol rate sampling for short-code DSSS signals intercepted from air,an efficient method using re-sampling technique was proposed for pseudo code estimation.Firstly,the strong autocorrelation characteristics of short-code DSSS signals was used to find the initial sampling points of pseudo code by sliding signal window. Based on this,the change of sampling rate was calculated,then the resampling of signals was completed,so that the number of sampling points on each DSSS element changed to the equal integer.Finally,pseudo code es-timation was realized by digital quadrature demodulation.Experimental results showed that the method could o-vercome the uncertainty of sampling decision point selection in pseudo code estimation based on non integer mul-tiple symbol rate sampling,and realized pseudo code estimation with validity and reliability.%针对以非整数倍码元速率的采样率对空中截获到的短码直扩信号采样给伪码估计造成的抽样判决困难,提出了有效利用重采样技术实现伪码估计的方法.该方法首先利用短码直扩信号的强自相关特性,滑动信号窗口找出伪码起始点;在此基础上计算采样率的变化情况,完成对信号的重采样,从而使得每个直扩信号码元上的采样点数变为相等的整数个,即将非整数倍采样问题简化为整数倍采样问题;最后用数字正交解调实现伪码估计.实验结果表明,方法能够克服非整数倍码元速率的采样率情况下伪码估计时抽样判决点选取的不确定性,实现有效可靠的伪码估计.