A comparison of three widely used GPS triple-frequency precise point positioning models
A comparison of three widely used GPS triple-frequency precise point positioning models
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DOI：
10.1007/s10291-019-0914-3
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发表时间：
2019-09
期刊：
影响因子：
4.9
通讯作者：
L. Pan;Xiaohong Zhang;Jing-nan Liu
中科院分区：
文献类型：
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作者：
L. Pan;Xiaohong Zhang;Jing-nan Liu
GPS Block IIF卫星可以发射三频信号。采用三频积分后，精密单点定位（PPP）的实现有了更多的选择，即采用L1/L2和L1/L5双频无电离层（IF）组合的PPP（IF-PPP 1）、采用三频IF组合的PPP（IF-PPP 2）和采用非组合（UC）测量的PPP（UC-PPP）。本文对三种GPS三频PPP模型进行了综合比较。在静态情况下，共使用了197个具有纯三频观测量的3小时数据集进行分析。证明了三种PPP模型在收敛阶段的数学等价性。三个三频PPP模型之间仅存在小于6 mm的精度差异。三种模型在东、北、垂直方向上的定位精度分别为37.2- 42.9mm、11.6- 13.0mm和36.2- 40.6mm。就平均收敛时间而言，IF-PPP 2表现出最好的性能，在三个方向上分别为29.7、11.0和29.9 min。在三个方向上，IF-PPP 2的平均收敛时间分别比IF-PPP 1提高了6%、3%和1%，比UC-PPP提高了17%、13%和20%。这些数值差异可能是由于三个三频PPP模式的参数化和噪声水平不同。
Triple-frequency signals can be transmitted by the GPS Block IIF satellites. With triple-frequency integration, more choices are available for the implementation of precise point positioning (PPP), namely the PPP using L1/L2 and L1/L5 dual-frequency ionospheric-free (IF) combinations (IF-PPP1), the PPP using the triple-frequency IF combination (IF-PPP2), and the PPP with uncombined (UC) measurements (UC-PPP). A comprehensive comparison of the three GPS triple-frequency PPP models is carried out in this study. A total of 197 3-h datasets with pure triple-frequency observables are used for analysis in the static situation. The mathematical equivalence among the three PPP models in the converged stage is proven. Only an accuracy difference of smaller than 6 mm exists among the three triple-frequency PPP models. For all the three models, the positioning accuracies are 37.2–42.9, 11.6–13.0 and 36.2–40.6 mm in east, north and vertical directions, respectively. As to the average convergence time, IF-PPP2 shows the best performance, which is 29.7, 11.0 and 29.9 min in the three directions, respectively. The improvement for IF-PPP2 on the average convergence time is 6%, 3% and 1% over IF-PPP1, and 17%, 13% and 20% over UC-PPP in the three directions, respectively. These numerical differences may be attributed to the different parameterization and noise levels for the three triple-frequency PPP models.