伽利略E1-BOC信号的改进捕获算法及性能分析

Improved acquisition algorithm and performance analysis for Galileo E1-BOC signal

在时域并行FFT捕获算法的基础上,采用在频率搜索维上基于能量搜索的策略对伽利略E1-Boc信号的捕获进行了仿真和实验分析.在伽利略仿真信号的码延迟时间为1.8ms,多普勒频移为600Hz,导航电文调制速率为250bit/s,数值为±1的情况下分别从捕获率、ROC操作特性曲线以及计算复杂性3方面对能量捕获算法性能进行了验证,并与AV,Zero-Padding两种算法进行了比较.结果表明,能量捕获算法在载噪比为32dB/Hz的室内微弱信号环境下,捕获率能达到90%,且ROC操作特性曲线和计算复杂性等综合性能均优于AV,Zero-Padding两种算法,适用于数据跳变发生频繁的微弱伽利略E1-BOC信号的捕获.

An energy-based acquisition method, based on the time domain fast Fourier transform with some modifications on frequency search space （FFT） parallel acquisition method, is proposed for Galileo E1-BOC signal. Performance analysis for this new acquisition algorithm is validated by simulation on Galileo E1 signals from the points of detection probability, ROC （receiver operating characteristic） operation characters curve and computational complexity. The simulation parameters are chosen like these： code delay time is equal to 1.8 ms, Doppler frequency shift is equal to 600 Hz, navigation data rate is equal to 250 bit/s and its value is ± 1. The result shows that this improved acquisition algorithm has a superior performance to the other two acquisition techniques （ AV and Zero-Padding algorithms）, with a high detection probability of 90% in indoor environment where the carrier to noise ratio is 32 dB/Hz. The energy-based acquisition method is suitable for the weak Galileo E1-BOC signals acquisition where the data transition happens frequently.