中文摘要：

提出一种改进的组合GPS/GLONASS精密单点定位（GG-PPP）算法,即首先利用传统的GG-PPP算法求得GPS-GLONASS系统时间差参数和天顶对流层延迟参数,然后将它们作为改进GG-PPP算法解算的先验信息,从而达到减少待估参数个数的目的.采用BJFS站的实测数据在一个模拟的露天矿区环境进行改进的GG-PPP算法试验.结果表明,在有限的卫星可视环境中,改进的GG-PPP算法能有效改善定位性能.

英文摘要：

A modified algorithm of combined GPS/GLONASS precise point positioning （GG-PPP） was developed by decreasing the number of unknowns to be estimated so that accurate position solutions can be achieved in the case of less number of visible satellites. The system time difference between GPS and GLONASS （STDGG） and zenith tropospheric delay （ZTD） values were firstly estimated in an open sky condition using the traditional GG-PPP algorithm. Then, they were used as a priori known values in the modified algorithm instead of estimating them as unknowns. The proposed algorithm was tested using observations collected at BJFS station in a simulated open-pit mine environment. The results show that the position filter converges much faster to a stable value in all three coordinate components using the modified algorithm than using the traditional algorithm. The modified algorithm achieves higher positioning accuracy as well. The accuracy improvement in the horizontal direction and vertical direction reaches 69% and 95% at a satellite elevation mask angle of 50°, respectively.