GPS/VRS 参考站网络的对流层误差建模技术研究

在虚拟参考站(VRS)技术中,参考站与流动站间的高程差异会引起对流层误差改正数中存在系统偏差影响,使对流层改正精度降低。在常规网络内插改正模型的基础上,借助先验对流层模型,提出了一种能自主修正高程偏差的距离相关对流层网络内插模型(MHDIM)。基于四川GPS连续运行参考站网络(Sichuan GPS Reference Station Network-SGRSN)实际测试数据的分析表明,对于地形变化较大的中长距离稀疏GPS/VRS参考站网络(如流动站与参考站间高程差异大于500m),应用MHDIM模型可使对流层延迟误差改正精度提高到2到3cm并实现cm级网络RTK定位结果,适用于GPS/VRS参考站网络cm级实时动态定位要求。

Research on tropospheric delay modeling technology based on GPS/VRS reference station network

The unmodelled residuals of tropospheric delay increase in mountainous area due to the height differences between the reference stations and rovers,which is specified as one of the main influence to the tropospheric correction accuracy in GPS/VRS real-time dynamic positioning. A network-based error reduction approach, i.e. “modified height and distance-based linear interpolation method (MHDIM)”, is proposed and the apriori tropospheric models are applied in this network approach to recover the homogeneous spatial correlation characteristic of the tropospheric delay. Test data acquired from SGRSN (Sichuan GPS reference station network) show that correction accuracy of 2 to 3 centimeter is reached over sparse networks with MHDIM. Furthermore, RTK field test shows that long range real-time dynamic differential GPS positioning at cm-level can be considerably improved when the proposed models are used.