Investigation of the GFS forecast products on RT-PPP solutions

Tropospheric delays play a key role in Precise Point Positioning (PPP). To achieve high precise positioning, these delays must be eliminated. In PPP, a priori delays and mapping functions (MF) are used to eliminate/model tropospheric delays. It can be seen in literature that the parameters obtained from Numerical Weather Models (NWM) increase the accuracy of the positioning. In addition to post-process applications of PPP, there is an increasing need of real time precise positioning to support recent technological developments. In this study, the effects of the a priori delays and MFs on real time PPP (RT-PPP) were investigated. Therefore, a case study was designed. In the study, two simultaneous RT-PPP analysis were performed by BNC software. In the first run, default configuration of the software was used. In the second run, a priori delays and MFs obtained using NCEP’s GFS forecast data were utilized. The delays and MF coefficients were derived by Direct Numerical Solution (DNS) ray-tracing tool. The effects of the parameters were compared by the parameters, convergence time, positioning and Zenith Tropospheric Delay accuracy. The results show that GFS utilized solutions converge the positions faster. Moreover, accuracy of the vertical component is also improved. • The potential use of numerical weather models in real time positioning is presented. • Convergence time improves by utilizing forecast model data. • Much more stable time series are obtained by following proposed approach.