TEST GEOID COMPUTATIONS IN PENINSULAR MALAYSIA

Precise geoid undulations information is required for the conversion of ellipsoidal heights to orthometric heights. Computation of the gravimetric geoid in the selected test areas in the region of Peninsular Aifalaysiahave been carried out using the latest compilation of available gravity data and the OSU91A gravity model. Three computational techniques namely numerical Stoke's integration, Fast Fourier Transform and Least Squares Collocation were used in the test. The data handling and computational strategies employed by the three techniques are described together with their comparison of results. The existing GPS network with stations at levelling benchmarks was chosen to test the accuracy of the computed gravimetric geoid. Results of the comparisons with GPS/levelling derived undulation differences indicate that it is possible to obtain relative geoid heights to a precision of ±20 cm or better after the removal of a systematic bias.