Evaluation of Global Gravitational Models Based on DGPS/leveling Data over Baghdad University (IRAQ)

Abstract

GPS becomes one of the most technical favorite geodesy methods. A major dilemma in GPS survey lies in oval-based elevations, while orthometric heights are commonly used in engineering practice. Converting GPS heights into orthometric heights by applying a precise geode model is therefore necessary. This paper aims to model the local geoid in the using study region (h-H). Compared with many global gravitational models (GGMs) and three of them were selected, namely EGM96, EGM84, and EGM2008. The evaluations of the accuracy of these models and then choose the most accurate and closer to the local geode In the field of work, which is mounted on the campus of the University of Baghdad in the capital of Iraq. Techniques require the use of GGM to represent global differences or long wavelengths of The gravity field of the Earth; the gravitational field of the Earth takes into account much of the direct information about the distributions of mass density in the Earth. It then provides the basis for exploring oil and gas in this respect, and the detection of geodesics forms the basis for exploring minerals. The EGM08 is the closer GGMs to the observed local geodetic dataset, in terms of the difference of geoid undulation that have a maximum of) 0.4011m), a minimum of) 0.3996m), an average of [-0.111256m], and a standard deviation of[ ±0.152859m].