卫星截止高度角和系统组合对GNSS PPP精度影响研究

为研究卫星截止高度角和GNSS系统组合对PPP精度的影响，对部分MGEX观测站10 d的实测数据分别进行24 h的精密单点定位数据处理，分析了5°~55°不同截止高度角下单系统GPS、BDS、GLONASS、双系统GPS/BDS、GPS/GLONASS、GLONASS/BDS、三系统GPS/BDS/GLONASS组合的可见卫星数以及定位精度。在确定的系统组合情况下，对不同截止高度角的定位精度分析表明，单系统定位的截止高度角应设置在30°以下，双系统应设置在40°以下，多系统应设置在55°以下；所有组合方式的最优截止高度角均在7°~15°；在确定的卫星截止高度角情况下，对不同系统组合的定位精度分析表明，当截止高度角小于40°时，定位精度最高的为GPS/BDS/GLONASS，最低的为BDS，其他系统组合居中；当截止高度角小于25°时，系统组合对定位精度的影响较为明显，随着截止高度角的增大（从25°到40°时），这种影响逐渐减小，当截止高度角进一步增大至40°时，主要依靠BDS卫星定位，能够进行定位的系统组合定位精度基本相当。

Influence of Elevation Masking Angle and System Integration on GNSS PPP Precision

In this paper, in order to study the influence of elevation masking angle and GNSS systems integration on PPP precision, we use the data from partial MGEX stations of 10 d are dealt with the PPP method of 24 h respectively. We analyze the number of visible satellites and the positioning precision of single GPS, BDS, GLONASS, double systems integration of GPS/BDS, GPS/GLONASS, GLONASS/BDS, and triple systems integration of GPS/GLONASS/BDS, under different elevation masking angle from 5° to 55°. The results show that the elevation masking angle should be set to under 30° in the single system, under 40° in the double systems, and under 55° in the triple systems. The optimal elevation masking angle of all system integration is from 7°
to 15°. When the elevation masking angle is less than 40°, the highest positioning precision is GPS/GLONASS/BDS and the lowest is BDS. When the elevation masking angle is more than 40°, it mainly depends on BDS to locate, and the positioning precision of all the system combinations is roughly equal. Moreover, as the elevation masking angle increases, the influence of systems integration on the PPP precision is gradually reduced.