Research Projects

The height of a point on Earth's surface can be defined as ellipsoidal or orthometric height. The geoid is an equipotential surface of Earth's gravity field, while the ellipsoid is a mathematical surface best fitting the geoid. GNSS observation provides ellipsoidal height, but it is purely geometrical and may not account for water flow. Orthometric heights are used in engineering, especially hydrology projects. Two widely used approaches are leveling and undulation. Gravimetric geoid modeling is used to estimate geoid undulations using Earth Gravitational Models (EGM). This project aims to develop a hybrid routine combining spatial and spectral techniques for faster computation time and accurate processing. The algorithm will use three data sources: EGM2008 gravity anomaly and geoid undulation, NOAA GRAV-D project airborne gravity data, and National Centre for Geodesy terrestrial gravity data.