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

  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.