GPS参考站网络的电离层延迟建模技术

Ionospheric Biases Modeling Technique for GPS Multiple Reference Stations

针对当前4种主要的网络RTK模型,研究用户流动站位置电离层延迟误差建模技术,建立了基于距离相关误差相关特性的电离层延迟误差改正数计算的统一形式,在此基础上对4种电离层延迟建模方法的特性及改正精度进行了分析.基于四川GPS连续运行参考站网络(GPSNOS)以及南加州集成GPS观测网络实测数据的分析表明,改正模型的精度和可靠性等指标受多种因素影响,存在明显差异;线性内插改正模型和线性组合模型用于200 km以下的中距离参考站网络,实现了优于2～5 cm的流动用户位置电离层延迟误差改正精度,证明是较优的电离层改正模型.上述模型用于虚拟参考站技术中,实现对包括电离层延迟误差在内的分类建模系统误差和精确改正,可有效提高中长距离网络RTK的定位精度.

Four typical methods to describe the ionospheric biases at the rover position were discussed to develop general formulas of correction generation models, both the advantages and disadvantages of each technique were summarized. Test data from both GPSNOS （ GPS reference station network of Sichuan） and SCIGN （Southern California integrated GPS network ） were used to evaluate the modeling techniques. The experimental results show that the linear interpolation model and the linear combination model are more reliable network solution with a correction precision of 2 to 5 cm reduction of the ionospheric biases for reference station networks with a baseline length of below 200 km. Real-time kinematic differential GPS positioning at cm-level can be considerably improved when the two models are used based on the virtual reference station technique to correct the systemic errors, including the ionospheric biases.