To date, the accuracy of static GPS positioning has been documented well. However, we have not yet encountered detailed evaluations for Rapid Static GPS. Considering this fact, in this paper the accuracy of Rapid Static GPS was investigated. BERNESE 5.0 was used to process the GPS data. GPS data was obtained from the archives of Scripps Orbit and Permanent Array Center (SOFA C). The results indicate that the accuracy of Rapid Static GPS depends on the inter-station height difference. As known from previous studies, a large inter-station height difference has a significant effect on GPS positioning accuracy, and this study modelled the effect with error equations. Empirical formulae are derived based on previously developed least squares (LS) functional models to predict the accuracy of GPS Rapid Static Positioning, and then an attempt is made to predict GPS baseline errors for the Koyulhisar landslide, in Central Turkey. The RMS of the solutions agrees with the predicted accuracy values at around the 1 cm level.