基于伽利略的线性偏移载波调制技术

LOC Modulation in Galileo

文中着重讨论伽利略卫星导航系统中采用的LOC调制技术,对LOC信号的基本特性作具体分析,提出副载波调制指数为奇数时应采用正弦类型的LOC信号,副载波调制指数为偶数时应采用余弦类型的信号。并在此基础上对LOC信号的多径误差、平均多径误差以及Gabor带宽进行仿真验证。仿真结果表明,对于副载波调制指数为偶数时的LOC(1,1)信号,余弦类型的平均多径误差优于正弦类型的平均多径误差,而对于副载波调制指数为奇数时的LOC(1.5,1)信号,正弦类型的平均多径误差优于余弦类型的平均多径误差。

In the future Galileo navigation satellite system, a new technology called linear offset carrier （LOC） modulation would be taken. In the paper, LOC modulation was analyzed in several aspects such as subcarrier waveform, power spectral density and autocorrelation function and spectrum , it was showed that cosine subcarrier signal was quite different from sine subcarrier signal. Multi-path error, average multipath error and Gabor bandwidth were given in the last part as the simulation result about LOC（1,1） and LOC（1.5,1）. The simulation result shows that when the subcarrier modulation index is even in the case of LOC （1.1）, average multipath error of cosine type is better than that of sine type, and when the subcarrier modulation index is odd in the case of LOC（1.5,1）, average multipath error of sine type is better than that of cosine type.