International Journal of Science and Technology (IJST)

Determination of Gravity Potential Differences and Height Systems for Survey Control on KNUST Campus, Ghana

Traditional spirit leveling remains the primary method for establishing height control in engineering and geodetic work. However, its results are affected by the specific path taken and are not purely determined by physics. Heights obtained solely through geometric leveling depend on the chosen route and cannot be directly integrated into global or regional height systems based on gravity potential. This study measures gravity potential differences between survey control stations on the KNUST campus in Kumasi, Ghana, and calculates orthometric, dynamic, and normal heights in accordance with physical height theory. Precise leveling was carried out among 16 existing control stations using a digital level and invar bar-coded staff. At the midpoint of each segment, ground gravity measurements were taken with a LaCoste & Romberg G-944 gravimeter. These gravity data were corrected for drift and tides using Geosoft, and geopotential numbers were computed from the segment height differences and average gravity values. From these geopotential numbers, orthometric, dynamic, and normal heights were derived for all stations. The results confirm that leveled heights are not unique and demonstrate that geopotential numbers offer a path-independent method to define height on campus. This study presents a practical approach to improve gravity-based vertical control in a local network, providing a foundation for future integration into national and global height systems.