针对多径环境下极微弱动态长周期伪码直扩(DS-SS)信号的捕获问题,拓展了单径环境下基于部分相关值与功率谱累积平均相结合的捕获算法,提出了多径环境下直扩信号的伪码捕获算法。该算法通过部分相关,得到了反映多普勒频偏的正弦信号,然后将部分相关值的功率谱累积平均,从而达到在多径环境下检测微弱信号的目的。给出了基于该算法的多径直扩信号模型,分析了该算法在多径环境下的捕获性能,通过计算机仿真验证了多径环境下该算法的可行性,并对比了多径和单径环境下的捕获效果。
For the problem of long PN code acquisition in weak multipath DS-SS communications,this paper proposed a capture algorithm,which developed the previous capture algorithm that was the combination of partial correlation and cumulative power spectrum based on the single path environment. It carried out the fast two-dimensional parallel search of PN phase delay and Doppler shift. Through partial correlation,it could get a sinusoidal signal,which reflected the Doppler shift,by an average of the cumulative power spectrum,it could achieve the purpose of weak signal detection in multipath environment. This paper gave the multipath DS-SS signal model. At the same time,analyzed acquisition performance over multipath environment. Finally,this paper presented the computer simulation results,which proved the feasibility of the algorithm and compared the acquisition performance in multipath and single path environment.