Abstract

Determination of the First Precise Geoid Model in the United Arab Emirates (UAE)

Dr. Shahrum Ses
Centre for Geodetic and Geodynamic Studies (CGGS)
shahrum@fksg.utm.my

Adel Khaleefh Alshamsi
Military Survey Department of the United Arab Emirates (UAE) Armed forces.
alshamsi@uaesurvey.ae

Abstract
This paper describes the computation of a gravimetric and a GPS-fitted geoid for the United Arab Emirates. The geoid computations are based on a new country-wide helicopter gravity survey at 5 km spacing of the entire U.A.E., as well as recompiled older oil company onshore and offshore gravity data.
The geoid computations are based on FFT and terrain reduction, using gravity field and topography results from the satellite missions GRACE and SRTM. The topographic from the Satellite Radar Topography Mission have been quality controlled in the eastern mountains of the UAE.
The computed gravimetric geoid is based on gravity and satellite data only, and is estimated by collocation to have a relative accuracy of 3-5 cm over most of the UAE.
To improve the systematic errors a geoid model fitted to GPS on leveling benchmarks is obtained from the gravimetric geoid by least-squares collocation fitting of residuals. The final geoid is to be used to determine orthometric heights H from GPS ellipsoidal heights h .The final GPS-fitted geoid is estimated to have 5 cm accuracy over most of the UAE.