精密单点定位中4种函数模型解算性能分析

Performance analysis of four function models for precise point positioning

文章针对PPP中4种不同的函数模型，分析了相应模型的特性，并采用IGS连续运行参考站179个测站数据对这4种模型进行解算，从定位精度、收敛速度、ZTD估计精度、解算时间等方面进行统计分析。实验结果表明，UofC、无电离层组合模型、非组合模型及无模糊度模型在30 min内达到厘米级的站点比例分别为75％、48.9％、51.7％、20.7％，平均收敛时间分别为22.6、36.1、40.9、126.3 min。在参数估计精度方面，无模糊度模型精度较低，其他3种模型单天解在N、E方向误差均值在1～9 mm左右，在U方向误差均值约为2 cm ，ZTD误差均值为10 mm左右，整体上参数估计精度具有一致性。

In order to evaluate the performance of four function models for precise point positioning （PPP） ,the model characteristics are analyzed ,and the daily static solution is obtained by using the observation data from 179 IGS tracking stations .Then the model performance is analyzed from the aspects of the positioning accura-cy ,convergence speed ,Zenith Tropospheric Delay （ZTD） estimation accuracy and solving time .The statistical results show that the percentage of sites with centimeter-level positioning accuracy within 30 min is 75% , 48.9% ,51.7% and 20.7% respectively and the average convergence time is 22.6 min ,36.1 min ,40.9 min and 126.3 min respectively ,when processed with UofC model ,ionosphere-free combined model ,uncombined model and ambiguity-free model .The accuracy of the ambiguity-free model is lower ,and for the first three function models ,the daily positioning accuracy of the north and east components is about 1-9 mm ,the up component is about 2 cm ,and the accuracy of ZTD is about 10 mm .On the whole ,the accuracy of positio-ning and ZTD have consistency .