Analysis and Estimation of Zenith Wet Delay and Zenith Tropospheric Total Delay at Earth’s different Geographical Areas

A comprehensive analysis is performed for the estimation of zenith troposphere delay (ZTD) and zenith wet delay (ZWD) from combined GPS/GLONASS precise point positioning (PPP) method. For this purpose, experiment is conducted from the dataset collected during winter and summer seasons from International GNSS service (IGS) stations at low, equator and high latitude areas. Results demonstrate that ZWD for the stations at higher latitude during winter and summer season is within 0.05 – 0.08 m and 0.14 – 0.17 m, respectively. While, estimates of ZWD for the stations at low region is within 0.12 – 0.15 m and 0.06 – 0.09 m for the winter and summer seasons, respectively. Furthermore, central regions have relative similar ZWD estimates during two different seasons. Additionally, ZTD estimates compare with respect to the corresponding IGS tropospheric delay ground values. Results demonstrate that estimates of ZTD at the equator has quiet similar trend during two seasons. While, at very high and very low latitude, large variation of ZTD is obtained.