新一代实时对流层映射函数精度及PPP性能评估

On the Accuracy and PPP Performance Evaluation of the Latest Generation of Real Time Tropospheric Mapping Function

  • 摘要: 采用射线追踪方法计算的斜路径总延迟(slant total delay,STD)作为参考,首先评估了最新一代实时对流层映射函数GPT3 (global pressure and temperature 3)、格网VMF3-FC(forecast Vienna mapping function 3)和站处VMF3-FC的STD建模精度,然后将3种映射函数用于北斗三号(BDS3)精密单点定位(precise point positioning,PPP),系统比较了3种映射函数计算的PPP坐标精度。结果表明,站处VMF3-FC 30°高度角时STD精度为2.3 cm,BDS3 PPP高程精度为9.8 mm,整体表现最优,推荐在有站处产品的IGS(international GNSS service)站处使用该映射函数产品;格网VMF3-FC 30°高度角STD精度为2.6 cm,BDS3 PPP高程精度为10.2 mm,整体表现次之,在无站处产品的情况下推荐使用;GPT3 30°高度角STD精度为7.0 cm,BDS3 PPP高程精度为10.5 mm,整体表现最差,但其可内嵌在定位软件中,在无需下载外部产品的情况下推荐使用。

     

    Abstract:
      Objectives  Real-time tropospheric mapping functions can be used into real time global navigation satellite system (GNSS) parameter estimation and applications, and it is therefore of great significance to evaluate their modeling accuracy and precise point positioning (PPP) performance.
      Methods  In this paper, the slant total delay (STD) modeling accuracy of the latest generation of real time mapping functions, including global pressure and temperature 3 (GPT3), grid-wise forecast vienna mapping function 3 (VMF3-FC) and site-wise VMF3-FC, is evaluated by taking ray-traced STD as a reference, and the BDS3 PPP performance of the three mapping functions is analyzed on the coordinate accuracy.
      Results  The results show that the site-wise VMF3-FC persists the best performance with STD accuracy of 2.3 cm at the 30° elevation angle and BDS3 PPP height accuracy of 9.8 mm, and it is recommended to use at the international GNSS service(IGS) stations with the site-wise products. The performance of the grid-wise VMF3-FC is a little worse with the STD accuracy of 2.6 cm and height accuracy of 10.2 mm, and it is recommended as the backup of the site-wise VMF3-FC products. The GPT3 model has the worst performance with the STD accuracy of 7.0 cm and height accuracy of 10.5 mm, while it can be embedded into the positioning software, so it is recommended to use in the case of without the need of external products.

     

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