GNSS服务空域空间信号可用性比较与分析

Comparison and Analysis of Signal Availability in the GNSS Service Volume

通过基本参数对全球卫星导航系统(GPS、GLONASS、Galileo和北斗)空间信号可用性影响实验,得出四系统的A knee值分别为3800km、1100km、3800km和1000km,对应的平均可见卫星数为25、16、22和14/22(亚太地区、MEO星座/混合星座)。分析了三种典型轨道用户的卫星可见性,北斗和GLONASS对MEO和HEO用户的空间信号可用性能较GPS和Galileo稍差,而在LEO用户的应用中,北斗空间信号可用性能却表现最优,平均可见卫星数约为20颗,可用性时间分布比较均匀。最后对GNSS空间有效持续时间段进行统计,随着用户高度的增加,有效持续时间段数增多、总有效持续时间减少;四系统提供全弧段有效服务空间分别为地面至6100km、1600km、6100km和1700km。

Based on the experiments of GNSS signal-in-space availability varying with 0HBW and Ak some results can be concluded： Aknee for GPS, GLONASS, Galileo and BeiDou is 3800km, 1100km, 3800km and 1000km respectively, and the corresponding average number of SVs is 25, 16, 22 and 14/22 （ MEO constellation/Integrated constellation for Asia Pacific region） respectively. Then the satellite visibilities for three typical user orbits are analyzed. Showing that signal availabilities of BeiDou and GLONASS are slightly worse than GPS and Galileo in MEO and HEO user orbits, and in LEO user orbit, BeiDou had the best performance that the average number of SVs is about 20, and the distribution of availability time is even. Lastly GNSS spatial effective continued time segment is analyzed, with the increment of user altitude the number of segments increases and the total effective time decreases. The space domain that GPS, GLONASS, Galileo and BeiDou could supply effective service （100% continued time segments） is from the earth surface to the altitude of 6100km, 1600kin, 6100km and 1700km respectively.