Towards the redefinition of the Egyptian geoid: Performance analysis of recent global geoid and digital terrain models

Launches of the CHAMP (CHAllenging Minisatellite Payload) and GRACE (Gravity Recovery And Climate Experiment) satellite missions have produced a new generation of global geopotential models (GGMs). The performance of seven recent GGMs has been analyzed using a local geodetic dataset (terrestrial gravity and GPS/levelling points) in Egypt. The results show that the EIGEN‐CG01C model is best at representing the long and medium wavelengths of the gravity field in Egypt. Its average accuracy, in terms of geoid undulations, when compared to known points, is estimated to be 0.36 m. Additionally, four digital terrain models (GTOPO30, SRTM, DTM2002, LDTM) have been investigated, leading to the conclusion that DTM2002 should be utilized in computing the terrain corrections for gravimetric geoid development in Egypt. When combined with local geodetic data, these two global models (EIGEN‐CG01C and DTM2002) will support the production of a precise local geoid model, to be used in conjunction with Global Positioning System‐based surveying and mapping projects in Egypt.

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