MSAS系统在中国区域服务性能评估与分析

Evaluation of MSAS System Service Performance in China Region

为了提高GNSS卫星导航系统服务性能,美国、欧洲各国、日本、印度、俄罗斯、韩国、中国已经建立或者即将建立独立的星基增强系统,通过提供广播星历差分与完好性增强信息,满足高精度高完好性用户使用需求。针对日本MSAS系统在中国区域SBAS增强服务性能不稳定的问题,在理解SBAS增强信息内容和处理流程的基础上,对分布在不同位置的日本两个站(GMSD、MIZU)和中国中东部区域3个站(天津、上海、武汉)的数据进行测试,采用GPS单点定位、MSAS增强单点定位和MSAS双频精密单点定位3种模式进行增强效果的评估和分析。结果表明,在中国区域采用MSAS电离层改正参数效果不佳,距离越远,精度改善程度越差。只采用轨道和钟差改正信息,较单点定位可实现10%的精度提升,精密单点定位可实现60%的精度提升,但需数十分钟的收敛时间,本文也给出了多方面的解决方法。

To improve the service performance of GNSS,many countries like USA,European countries,Japan,India,Russia,Korea,and China have established or are establishing Satellite-Based Augment System,providing the broadcast ephemeris differential integrity message to satisfy the high precision and the high integrity user’needs. For solving the problem that the service accuracy over China of Japanese MSAS system is uncertain,two stations distributed in Japan(GMSD,MIZU) and three stations distributed in China east(Tianjin,Shanghai,Wuhan) were used for testing to evaluate and analyze the enhance effect by three methods of GPS standard point positioning(SPP),standard point positioning(SPP) with MSAS enhancement information,and precision point positioning(PPP) with MSAS enhancement information. The results show that the effect of using MSAS ionosphere correction over China region is unsatisfactory,and the farther the distance,the worse the accuracy. However,the positioning accuracy of SPP and PPP can respectively improve 10% and 60% with only orbit and clock correction are adopted,but PPP takes a couple of minutes of convergence time,a variety of solution are given in this paper.