北斗弱信号跟踪相干积分算法设计  

Beidou weak signal tracking algorithm based on coherent integration

作　　者：韩志凤 刘建业[1,2] 李荣冰 王翌[1,2] HAN Zhi-feng;LIU Jian-ye;LI Rong-bing;WANG Yi(Jiangsu Key Laboratory of Internet of Things and Control Technologies, Nanjing 211106, China;College of Automation Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China)

机构地区：[1]江苏省物联网与控制技术重点实验室,南京211106 [2]南京航空航天大学自动化学院,南京211106

出　　处：《控制与决策》2018年第7期1282-1286,共5页Control and Decision

基　　金：国家自然科学基金项目(61374115);江苏省研究生培养创新工程项目(KYLX-0283);中央高校基本科研业务费专项资金项目;南京航空航天大学博士学位论文创新与创优基金项目(BCXJ14-06)

摘　　要：为了提高北斗接收机弱信号跟踪灵敏度,解决北斗信号中NH码跳变和比特跳变频繁限制相干积分时间加长的问题,提出一种基于相干积分的北斗弱信号优化跟踪算法.首先,利用分组比特匹配方法进行位同步/帧同步算法优化,实现全比特相干积分;然后,采用最大似然法对数据比特值进行估计和解码,实现跨比特相干积分;最后,利用卫星导航系统开发平台开展仿真验证,分别实现了20 ms和40 ms时间的相干积分,结果表明,采用40 ms积分后信噪比提升约16 d B.所提出算法能够稳定可靠地实现北斗信号位同步和帧同步功能,并快速地剥离NH码,消除数据比特跳变和NH码相位变化的影响,可实现全比特相干积分和跨比特相干积分,有效提高北斗弱信号跟踪灵敏度.In order to improve the tracking sensitivity of the Beidou receiver and solve the problem that the data bits and NH code phase changes limit coherent integration time, a weak signal tracking algorithm based on coherent integration is proposed. Firstly, an optimized bit synchronization/frame synchronization algorithm is designed with bits matching in groups to realize coherent integration within bits. Then, the maximum likelihood estimation method is used to estimate bit reversions to realize coherent integration over bits. Finally, software receiver simulation is carried out. Correlation tests of 20 ms and 40 ms are realized and the signal-to-noise ratio increase about 16 d B. The simulation results show that the bit synchronization method is able to achieve stable and reliable signal synchronization. With bit synchronizing and NH code solving, it can realize coherent integration within or across bits, and effectively improve the tracking sensitivity of the Beidou weak signal.

关 键 词：弱信号 NH码 高灵敏度 相干积分 

分 类 号：V249.3[航空宇航科学与技术—飞行器设计]