GPS/GLONASS/BDS广播星历轨道误差分析

针对GPS、GLONASS、BDS组合定位中观测值定权的问题,利用广播星历计算卫星位置,以IGS提供的精密星历为参考,将卫星坐标的三维均方根误差与附有加权因子的用户等效距离误差作为精度指标,对各系统轨道误差进行对比分析,找寻其规律。对2013、2014、2015各年8月份轨道误差进行分析,结果表明BDS系统在逐步完善,GPS/GLONASS/BDS 3系统轨道误差的权比在3年间显示出5∶2∶1、5∶2∶2、5∶2∶3的变化。以后的组合定位观测值可参考2015年的权比定权。

Error analysis of orbit determined by GPS/GLONASS/BDS broadcast ephemeris

Aiming at the problem of determining measurement's weight ratio in GPS/GLONASS/BDS combined positioning,this paper calculated the positions of satellites via broadcast ephemeris,with reference to the precise ephemeris provided by IGS,the root-mean-square of coordinate of satellite and user equivalent range error with weight factor as accuracy indication.Then the law of orbit error was explored through comparison and analysis of the indications.The analysis of orbit errors in each August of 2013,2014 and 2015 shows that the BeiDou satellite navigation and positioning system is being improved gradually and the orbit errors' weight ratio of GPS/GLONASS/BDS is changing at 5 ∶ 2 ∶ 1、5 ∶ 2 ∶ 2、5 ∶ 2 ∶ 3 during the three years.Future measurement's weight ratio can refer to the weight of 2015.