CBOC调制导航信号跟踪算法研究及实现

Research and implementation of tracking algorithm for CBOC modulation navigation signal

复合二进制偏移载波(CBOC)信号的子载波是四电平的扩频符号,增大了接收机相关基带码的处理难度.针对此问题,本文分析了CBOC(6,1,1/11)信号的跟踪性能,并根据其子载波的特性,改进了TM61跟踪算法.该方法在跟踪的初始阶段利用BOC(1,1)进行同步,实现稳定跟踪后改用BOC(6,1)以提高跟踪精度.最后在自主研发的硬件平台上对该算法进行了验证.结果表明在保证跟踪精度的前提下,该方法有效的解决了由BOC(6,1)多峰现象引起的错锁问题,并且降低了对捕获精度的要求.

With 4-level Sub-carrier,the Composite Binary Offset Carrier （CBOC） signal increases significantly difficulty of processing baseband code in navigation receiver.This paper analyzes the tracking performance of CBOC（6,1,1/11） signal,and improves the TM61 tracking algorithm according to the characteristic of sub-carrier.This method adopts BOC（1,1） to synchronize the signal at the initial stage of tracking,and uses BOC（6,1） to enhance the accuracy of tracking after achieving stable synchronization.Finally,the proposed method is validated by independently developed platform hardware.The results show that under the premise of ensuring accuracy of tracking,the proposed method effectively solves the problem of false locked caused by multiple peaks of BOC（6,1） autocorrelation function,and reduce the request of accuracy of acquisition.