An Evaluation of Tropospheric Delay on GNSS Observations

Abstract

The Global Navigation Satellite System is used to find point locations in latitude, longitude, and altitude which are involved among the satellites and receivers through electromagnetic signals. Due to the refraction of the electromagnetic signals, the signals are delayed than the actual propagation time. In this study, the effect of tropospheric delay on GNSS observations is considered by single-point observation on a primary control point of the Sri Lanka Datum 99 network. The study aims to investigate the total tropospheric delay of GNSS observations affected at different times of the day without considering dry and wet components of the delay. The 24 hours of dual-frequency row data were collected and processed separately on the morning, afternoon, and evening observations using Leica Geo Office 8.4 software applying Hopfield, Simplified Hopfield, and Saastamoinen models to correct the tropospheric delay. Then fulfill the purpose to identify the variation of GNSS observations affected at different times of the day due to the tropospheric delay, determine the best tropospheric model which can be used to minimize tropospheric delay, and define the best time for getting Global Navigation Satellite System observations. The Saastamoinen model shows the minimum variation toward the original values of the A166 primary control point. The morning was the best time for collecting data for Global Navigation Satellite System purposes according to this study.