Estimating Offsets the Syrian Height Datum and the EGM2008 Geoid using the Normal Gravity Field


Abstract in English

Within the last thirty years, the recent development in GPS, satellite tracking techniques and processing strategies has revolutionized development of Earth gravity field models. In addition, the increase of gravity data coverage led to an increase in the resolution and accuracy of these models. This in turn led to a noticeable improvement in determination of geoid surfaces which are essential in transformation of the geodetic height to the orthometric height. This study utilizes the normal gravity field for estimating offsets the Syrian leveling network from the EGM2008 geoid defined by its geopotential value W0=62636856.0 m2s-2. This approach uses the average of the gravity potential values at the GPS/levelling points in some areas in Syria. The gravity potential value in the study regionis estimated using the Earth gravity field model EGM2008. The residuals between the actual gravity potentials and the values at the Syrian height reference surface are estimated in the range between [-4.51 m2s-2 ~ 10.62m2s-2] and a mean value of -6.72±0.70 m2s-2 with 95% confidence level. This corresponds to [-46.0 cm ~ 108.4 cm] and a mean value of -63.7±7.1 cm which means that the Syrian height datum is located underneath the global geoid.

References used

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