Evaluation of Global Geopotential Model and Its Application on Local Geoid Modelling of Java']Java Island, Indonesia

The geoid is the ideal height reference field that used as the basis of the height measurement and also transferring the GNSS height data to become the practically utilized orthometric height data. In this study, 7 Global Geopotential Models (GGMs) have been evaluated and applied for precise local geoid modelling of Java Island. The Evaluation had been done through the comparison, absolutely and relatively, with 44 co-site GPS-levelling data. Base on the evaluation results, the optimal GGM had been utilized on precise local geoid model using the standard remove-restore method and the residual geoid has been computed using the 2D-FFT method. Effect of degree and order of GGM to the local geoid have also been investigated. The comparison of The GGMs and GPS-levelling showed that the EGM2008 gave best results with the mean difference value of 0.99 and 0.701, absolutely and relatively, and also shows consistency over the distance. The effect of degree and order of EGM2008 to the accuracy of the local geoid model ranged from 0.706 to 0.596 m from degree 2190 and 750. Finally, the local geoid model derived using the full resolution of EGM2008 has been fitted to the local reference, in this case, the GPS-levelling data with an accuracy of 0.204m.