Improving Long Baseline (100–300 km) Differential GPS Positioning Applying Ionospheric Corrections Derived from Multiple Reference Stations

Abstract

The aim of this study is to develop a method to mitigate the ionospheric delay bias in long baseline differential global positioning system (GPS). The ionospheric delay is the main source of error when single frequency GPS receivers are involved in surveys with baselines which exceed a few tens of kilometers. This article presents a technique that estimates the vertical total electron content (VTEC) in several continuously operating reference stations (CORS) and computes the slant total electron content (STEC) for the receiver of unknown coordinates. VTEC was obtained from the La Plata ionospheric model and an interpolation strategy was implemented in order to calculate STEC values. Networks covering different areas and baseline sizes are studied. The strategy presented in this article could be particularly useful when the accuracy of one decimeter is required and reference stations used are a few hundred kilometers away since it provides a 50% improvement in position accuracy.