Evaluation of EGM96 and EGM08 Based on GPS/Levelling Heights in Egypt

Abstract

The heights obtained by the GPS are referring to the ellipsoid called World Geodetic System 1984 (WGS84). The available Global Geopotential Models (GGMs) on GNSS commercial software are used to transform the ellipsoidal heights to orthometric heights. The geoid heights using 17 GPS/Levelling stations of the High Accuracy Reference Network (HARN) over Egypt were computed to evaluate the accuracy of geoid heights obtained from two GGMs, EGM96 and EGM08. The standard deviation of the differences between the geoid heights obtained from GPS/Levelling and geoid heights obtained from the EGM96 and EGM08 are ± 1.212 m and ± 0.543 m respectively. This research illustrates that geoid heights obtained from EGM08 are closer to the geoid heights determined using GPS/levelling over Egypt.