基于循环谱的GPS信号快速捕获算法

本文提出了一种基于循环谱理论的GPS信号捕获的新方法。将循环谱理论应用到GPS系统中,采用频域平滑周期图法估计出GPS中频信号的循环谱,分析循环谱的幅度、相位和位置信息,从而实现对其载波频率、伪码速率和初始相位的估计。本文还对伪码速率的估计算法提出了改进。最后,对捕获过程进行计算机仿真验证,证明了该算法的有效性。这种捕获方法避免了多维搜索,很大程度上减小了平稳噪声和干扰的影响,估计精度高,适用于低信噪比情况。

Rapid acquisition algorithm for GPS signals based on spectral correlation analysis

A novel method of acquiring the GPS signal based on the theory of spectral correlation is presented.The cyclic spectrum of GPS IF(intermediate frequency) signal is estimated by means of frequency-domain smoothing symmetrical periodogram.Through analyzing the magnitudes,phases and positions information of cyclic spectrum,an estimation of carrier frequency,chip rate and initial phase is complemented.Also,the chip rate estimation algorithm is improved.Finally,it is proved by computer simulation to show that the algorithm is effective.This estimation method,which can weaken the affection of stationary noise and interference,is suit to the situation of low-SNR.Moreover,it is computationally efficient due to avoiding multi-dimensional search and has a high estimating accuracy.