BOC信号的伪码周期和组合码盲估计

针对在低信噪比下存在残余频偏的BOC(Binary-Offset-Carrier)调制信号的伪码周期以及组合码(扩频序列和副载波序列的组合)盲估计问题,提出了功率谱二次处理结合矩阵分解的方法。该方法首先对存在残余频偏调制的BOC信号进行二次功率谱运算,所得二次功率谱中会在伪码周期及整数倍出现尖锐的脉冲,通过检测峰值间的距离估计信号的伪码周期,然后对信号采样并按伪码周期分段构成数据向量,计算相关矩阵并进行奇异值分解,最后搜索最大和次大奇异值以及对应的向量估计出组合码序列。仿真分析表明,该方法能够在较大频偏和较低的信噪比下达到较精确的估计性能。相关研究对于从事卫星导航接收机设计的工程技术人员具有一定的参考价值。

Blind estimation of pseudo code period and combination code for BOC signals

For the blind estimation problem of pseudo code period and combination code(combination of spread spectrum sequence and subcarrier sequence) for BOC(Binary-Offset-Carrier) signals with residual carrier at the low signal-to-noise ratio(SNR),the method which combines the second power spectrum with matrix decomposition is proposed.First,this method calculates the second power spectrum of BOC signals with residual carrier.There are sharp pulses appearing at the integer times period of the pseudo code. Detecting distance of these peaks can estimate the period of the pseudo code.Then the sampling signals are sectioned according to the period of the pseudo code to get the data vector.The correlation matrix of the data vector is calculated and matrix decomposition of the correlation matrix is performed.The combined code sequence can be estimated with the two largest singular values and their vectors.The simulation results show that the method has accurate estimation performance for the signals with larger residual carrier at the lower SNR.The research in this paper has a certain reference value for those engaged in satellite navigation receiver design.