AFRC-Trop: New Real-Time Zenith Tropospheric Delay Model over Africa

This study aims to develop a new real-time zenith tropospheric delay (ZTD) model over Africa, namely the AFRC-Trop model. In order to estimate the ZTD, global positioning system (GPS) observations from 14 reference stations are processed in the precise point positioning (PPP) mode using the international global navigation satellite system (GNSS) real-time service (IGS-RTS) products. Then, the Kriging interpolation technique is used to compute the ZTD for a 1 degrees x 1 degrees grid at a 1-h time interval. The AFRC-Trop-derived ZTD is validated with respect to the IGS and the Center for Orbit Determination in Europe (CODE) tropospheric products counterparts. The computed ZTD are compared as well with the very-long-baseline interferometry (VLBI) tropospheric products. Additionally, the proposed model is validated with the empirical tropospheric models, namely the University of New Brunswick (UNB3m) and the Global Pressure and Temperature 2 Wet (GPT2w) models. The findings indicate that the newly developed AFRC-Trop model shows good agreement within a few centimeters with the IGS, CODE, VLBI, UNB3m, and GPT2w models. (C) 2021 American Society of Civil Engineers.