基于频域差分的“北斗”三号信号快速捕获算法

A Fast Acquisition Algorithm of BDS-3 Signal Based on Differential Non-coherence in Frequency Domain

针对“北斗”三号导航信号快速捕获问题,提出了一种能够克服“北斗”三号信号中Neuman-Hoffman(NH)码跳变并提高“北斗”三号导航卫星信号B1I频点信号信噪比的快速捕获算法。该算法基于频域差分非相干的部分匹配滤波和快速傅里叶运算(Fast Fourier Transform,FFT)算法,利用加窗和补零的方式提高FFT的频点分辨率并抑制扇贝损失,通过频域差分的方式弥补相干积分时间短和非相干平方损失带来的信噪比不足。理论分析和仿真实验证明,该算法优于传统非相干积分,能实现“北斗”三号信号的快速捕获。

A fast acquisition algorithm which can overcome the level upturn of Neuman-Hoffman(NH)code in Beidou navigation satellite system(BDS)-3 and improve the signal-to-noise ratio(SNR)of B1I signal is proposed to address acquisition problem of BDS-3.This acquisition algorithm is based on differential non-coherence in frequency domain.Partial matched filter-fast Fourier transform(PMF-FFT)uses windows and zero padding to suppress scallop loss and uses differential non-coherence in frequency domain to compensate the shortage in SNR caused by non-coherence.According to theoretical analysis and simulation,the algorithm is confirmed to be better than traditional non-coherence.It can be used to capture BDS-3 signal rapidly.