Usage of a Correction Model to Enhance the Evaluation of the Zenith Tropospheric Delay

摘要

Tropospheric delay values are calculated only from global positioning system observations; however, if the global navigation satellite system data sites are unavailable or unrepresentative, the tropospheric delay is degraded resulting in an incorrect estimation. Currently in the GPS processing, tropospheric delay is estimated by the determination of priori values of total delay using a correction model, e.g. Global pressure and temperature model with global mapping function. This article proposes three mathematical models for the zenith tropospheric delay correction based on real GPS data and calculated by the Bernese software. The first model uses logarithmic function and the second uses rational function. The third has a high level of accuracy and shows a consistently smaller variation over the other two. The variation as represented by the standard deviation is larger for the second model. These models are evaluated and compared to the correction data given by the national institute of geographic information.