基于伪码子序列分段叠加的快速捕获算法  

Fast Acquisition Algorithm Based on Segmentation and Accumulation of Pseudo-code Subsequence

作　　者：刘燕丽[1] 张天骐[1] 黄铫[1] 苗圃[1] 

机构地区：[1]重庆邮电大学信号与信息处理重庆市重点实验室,重庆400065

出　　处：《探测与控制学报》2010年第2期51-55,59,共6页Journal of Detection & Control

基　　金：国家自然科学基金-中物院NSAF联合基金项目资助(10776040);国家自然科学基金项目资助(60602057)

摘　　要：长周期伪码具有码片速率高、抗干扰等优点,许多扩频通信系统采用了长周期扩频码,但是由于其伪码周期长给捕获带来了一定的难度。针对现有长周期伪码捕获方法速度慢、频偏补偿精度低的问题,提出了一种基于伪码子序列分段叠加的快速捕获方法。该方法将本地伪码序列分为4个子序列,对每一子序列进行分段重叠累加形成新的子序列,然后将新的4个子序列构成两个联合参考序列。接收信号则以四分之一伪码速率进行抽样,将抽样序列与两个联合参考序列通过使用FFT进行快速相关运算来达到长周期伪码捕获的目的。理论分析和计算机仿真结果表明,该方法扩大了搜索范围、提高了捕获速度和频偏补偿精度,具有良好的捕获效果。Long pseudo-code features high chip rate and strong anti-jamming property and it is widely used in spread-spectrum communication system. However, it is difficult to be captured due to its long period. To solve the problems with long pseudo-code such as slow capture speed and low precision of frequency offset compensation,a method based on segmentation and accumulation of the pseudo-code is proposed. This method divides the local pseudo code sequence into four suhsequences, and then each of them is partitioned,overlapped,and accumulated to get four new sequences, which are then formed into two joint reference sequences. Then correlation is done between the two joint reference sequences and the received signal sample sequence which is sampled with a quarter of chip rate. The theoretical analysis and simulation results prove that this method which extends the searching scope of local pseudo-noise code, improves the acquisition speed and the precision of frequency offset compensation has good acquisition efficiency.

关 键 词：长伪码DS-SS信号 伪码序列 伪码捕获 相关 

分 类 号：TP391.9[自动化与计算机技术—计算机应用技术]