The mount Cameroon height determined from ground gravity data, global navigation satellite system observations and global geopotential models

AbstractThis paper deals with the accurate determination of mount Cameroon orthometric height, by combining ground gravity data, global navigation satellite system (GNSS) observations and global geopotential models. The elevation of the highest point (Fako) is computed above the WGS84 reference ellipsoid. The geoid undulation and the height of Fako above mean sea level were also determined. Ground data consist of a sparse gravity net recorded around 1950, densified with recent data collected on and around the mountain. GNSS data consist of ellipsoidal elevations and precise horizontal point coordinates computed from GPS satellites observations, and those of other systems orbiting around the Earth. Global geopotential models involved are a hybrid model EGM-GGM and the recent Earth Gravity Model EGM2008. The method used appears more flexible than spirit leveling, which is too expensive, time consuming, difficult and of very low accuracy in mountainous areas, where the topography is very rough. Mount Cameroon, which is the highest summit in central and western Africa, is now known to culminate at 4037.7 ± 0.7 m above sea level. This height is nearly 60 m less than the approximate value of 4095 m published by the National Institute of Cartography.