一种改进的非相干GNSS信号频率锁定方法  

Improved non-coherent accumulation GNSS weak signal frequency tracking approach

作　　者：阮航[1] 刘峰[1] 张磊[1] 龙腾[1] 

机构地区：[1]北京理工大学信息与电子学院,北京100081

出　　处：《华中科技大学学报（自然科学版）》2014年第5期122-127,共6页Journal of Huazhong University of Science and Technology(Natural Science Edition)

基　　金：国家自然科学基金项目资助(61101128)

摘　　要：为了实现弱信号环境中的高灵敏度GNSS信号跟踪,提出了一种改进的非相干GNSS信号频率锁定方法,利用非相干累积消除电文反转的影响,扩展有效能量累积时间范围,改善了信噪比;设计了基于非线性加权累积偏差的最优频率间距计算方法,得到频率鉴别线性范围最大的非相干频率鉴别器;通过延长相干和非相干累积时间,实现宽线性鉴频范围的高灵敏度频率锁定环路.理论分析和蒙特卡罗仿真结果表明:所提出的方法可以改善频率跟踪灵敏度和牵引范围,在不进行电文估计、静态环境信号强度为-160dBm的情况下,可以实现稳定跟踪并保证一定精度.In order to realize high sensitivity GNSS （global navigation satellite system） signal tracking in the environment of weak signal, an improved non-coherent GNSS signal frequency locking method was proposed, which solved the problem of navigation inversion to expand the available range of pow- er accumulation length and increase the signal to noise ratio. A frequency space calculation method was designed based on accumulated nonlinear weighing error to gain the optimum linear non-coherent discriminator which has the largest linear frequency discrimination range. By extending the coherent and non-coherent accumulation, a high sensitivity frequency lock loop with a wide linear frequency dis- crimination range was realized, which could be applied to improve sensitivity. After the theoretic analysis and Monte Carlo simulation of the noise affection and the frequency convergence range, it is claimed that the frequency tracking sensitivity is improved and the signal with power of --160 dBm can be steadily tracked without navigation estimation and with a certain accuracy.

关 键 词：弱信号 锁频环 归一化 非相干累积 非线性偏差 

分 类 号：TN967.1[电子电信—信号与信息处理]