Determination of the Orthometric Height inside Mosul University campus by using GPS data and EGM96 Geoid Model

ABSTRACT In the geodesy science, the heights determined by Global Positioning System (GPS) measurements are related to the perpendicular distance above the reference ellipsoid, while heights of Mean Sea Level (MSL) are determined with respect to geoid. The datum that defines the MSL (also called the geoid) is a complex surface that requires dense and accurate gravity data to define its shape. Determining the geoid in Iraq is not an easy matter, mainly because of the lack of necessary data at the present time. In the present simple study, ellipsoidal heights were derived from GPS measurements) with respect to WGS84 reference ellipsoid) at specific locations inside the campus of Mosul University. Orthometric heights (MSL) data of the test locations were then obtained according to geoid undulation (geoid height) given by the global model of the geoid (The Earth Gravitational Model 1996: EGM96). From the result of the measurements, a geoid map was produced for the study area. This study is being considered as primary attempt, so later in the future the whole geoid separation of Iraq can be measure or part of Iraq, I hope so.