北斗星基增强系统性能评估

Beidou Satellite-based Augmentation System Performance Evaluation Analysis

以实际广播星历、精密星历和北斗星基增强系统(BDSBAS)增强报文为实验数据,通过计算BDSBAS轨道误差、卫星钟差、空间信号测距误差和BDSBAS格网电离层有效点、播发时间和电离层延迟误差6个指标,评估分析了BDSBAS空间信号的性能。结果显示:BDSBAS增强后的GPS卫星轨道误差在切向、法向、径向分别降低了34.57%,40.57%,30.90%;卫星钟差均方根降低了24.31%,卫星钟差标准差降低了16.8%;空间信号测距误差相比增强前降低了32.75%;BDSBAS格网电离层有效点覆盖了中国及周边地区;BDSBAS各点电离层延迟播发间隔均达到ICAO对精确差分定位的要求;电离层延迟在0°-5°N范围内误差在0.4 m以上,可信度均达到99.9%,在5°-55°N范围内误差小于0.4 m,可信度均为100%;BDSBAS水平定位误差提升超过25%,垂直定位误差提升超过50%,完好性均在99.9%以上。

In this paper,the performance of the BDSBAS space signal was evaluated and analyzed by calculating six indicators:BDSBAS orbit error,satellite clock difference,space signal ranging error and BDSBAS grid ionospheric effective point,broadcast time and ionospheric delay error,using actual broadcast ephemeris,precision ephemeris and augmentation messages of Beidou Satellite-Based Augmentation System(BDSBAS)as experimental data.Results showed that the orbital errors of GPS satellites after BDSBAS enhancement were reduced by 34.57%,40.57%and 30.90%in tangential,normal and radial directions respectively;the root mean square of satellite clock deviation was reduced by 24.31%,and the standard deviation of satellite clock deviation was reduced by 16.8%;the spatial signal ranging error was reduced by 32.75%compared with that before enhancement;the effective ionospheric points of BDSBAS grid.The ionospheric delay broadcast interval of all BDSBAS points meets ICAO’s requirements for accurate differential positioning;the ionospheric delay error in the range of 0°-5°N is more than 0.4 m with a confidence level of 99.9%,and in the range of 5°-55°N,the error is less than 0.4 m with a confidence level of 100%;the horizontal positioning error of BDSBAS is improved by more than 25%improvement in horizontal positioning error and over 50%improvement in vertical positioning error,all with an integrity of 99.9%or more.