GLONASS辅助动态GPS精密单点定位模糊度固定

GLONASS Aided Ambiguity Fixing for Kinematic GPS PPP

与模糊度为浮点解的精密单点定位(precise point positioning,PPP)相比,PPP模糊度固定技术具有更快的收敛速度和更好的定位精度。但当GPS卫星数目少或几何构形不好时,需要较长时间实现GPS PPP模糊度的首次固定,通过加入GLONASS卫星可以有效缩短首次固定时间。推导了基于整数相位钟法的GPS/GLONASS组合PPP模型并进行了大量实验解算。40组静态模拟动态实验表明,GPS PPP模糊度首次固定平均需要50.2min,但在GLONASS辅助下只需25.7min,减少了48.8%,而且定位精度也有提高。车载动态实验表明,由于受观测条件限制,GPS PPP模糊度难以固定,但在GLONASS辅助下仍能实现GPS PPP模糊度固定。

Compared to ambiguity-float precise point positioning（PPP）,ambiguity-fixed PPP needs a short convergence time and has better positioning accuracy.However,when there are only a few GPS satellites without an optimal geometrical distribution,ambiguity-fixed PPP requires time to achieve a first fixed solution.The objective of our research was to reduce the time to first fixed solution（TFFS）for GPS-only PPP by adding GLONASS satellites.An observation model for GPS/GLONASS ambiguity-fixed PPP using the integer phase clock method was developed and tested.Forty kinematic tests using static data show that the average TFFS is 50.2min for GPS ambiguity-fixed PPP while only 25.7min for GPS/GLONASS ambiguity-fixed PPP;reduced by 48.8% after adding GLONASS observations.A vehicular test demonstrates that GPS-only PPP cannot get its first fixed solution due to a less than ideal observation environment while GPS/GLONASS PPP can realize ambiguity fixing.