多径BOC信号捕获性能分析

针对多径情况下存在一阶多普勒变化率的高动态二进制偏移载波(Binary Offset Carrier,BOC)信号捕获困难的问题,本文提出了基于部分匹配滤波器(Partial Matched Filter,PMF)和分数阶傅里叶变换(Fractional Fourier Transform,FRFT)相结合的多径情况下高动态BOC信号的捕获算法。该算法首先利用PMF对信号进行分段积分处理,然后利用FRFT所具有的使不同的线性调频信号(Linear Frequency Modulated,LFM)在不同的FRFT域呈现能量聚集的特性确定直达信号,最后在直达信号所对应的最优FRFT域完成对BOC信号的捕获。该算法可以在确定直达信号的同时抑制除直达信号外的多径信号,通过仿真结果可知,该算法可以在信噪比为-7 dB的情况下实现对存在一阶多普勒变化率的多径BOC信号的捕获。 

Performance Analysis of Multipath BOC Signal Capture

In order to solve the problem of difficult acquisition of high dynamic binary offset carrier (BOC) signal with first-order Doppler rate in multipath environment, this paper proposes a method based on partial matched filter (PMF) and fractional Fourier transform (FRFT) The acquisition algorithm of high dynamic BOC Signal in multipath environment is proposed. Firstly, the partial matched filter is used to process the signal by segments. Then, the direct signal is determined by using the characteristic of fractional Fourier transform that makes different LFM signals present energy aggregation in different fractional Fourier transform domains. Finally, BOC signal is captured in the optimal fractional Fourier transform domain corresponding to the direct arrival signal. The algorithm can determine the direct signal and suppress the multipath signal except the direct signal. The simulation results show that the algorithm can achieve the acquisition of multipath BOC Signal with first-order Doppler change rate when the signal-to-noise ratio is - 7dB.