Interpolating Residual Zenith Tropospheric Delays for Improved Regional Area Differential GPS Positioning

Abstract

This paper examines the use of the Ordinary Kriging method to interpolate the residual zenith tropospheric delay (ZTD) within a regional area GPS network in an attempt to improve the positioning accuracy. The ZTD solutions from 129 EUREF Permanent Network (EPN) stations across Europe for over 3 months were collected for this study. The results and analysis demonstrate that with the interpolating procedure applied to residual ZTDs, the overall standard deviations of zenith tropospheric corrections are improved from 3–4 cm, achievable with the Saastamoinen model (using standard meteorological data) and the Global Tropospheric Navigation (GTN) model, down to 1–2 cm, while the overall bias of the Saastamoinen model is also dramatically reduced from 14 mm to nearly zero. The results demonstrate that interpolating residual zenith tropospheric delays is an efficient way to improve regional area differential GPS positioning.