Normal Gravity Field Computation for the Evaluation of Terrestrial Reference Systems for the Modeling of Gravity Anomalies in Cameroon

The choice of a terrestrial reference model over another in view of the duplicity of reference systems within a single territory is discussed. To do this the calculation of the normal gravity fields of the GRS 80 and WGS 84 reference systems was performed in order to evaluate the accuracy of the two models on Cameroon. The study was done by descriptive statistical analysis using regional modeling and local modeling of the normal gravity field. The examination of some results shows an equivalence of some parameters for the two reference systems, notably the normal gravity averages estimated at 978121 19.1 mGal for regional modeling and 978043 0.13 mGal for local modeling. The standard error value of the normal gravity field difference between the two reference systems is evaluated to 0.0000007 mGal, which suggests that there is little difference between the GRS 80 and WGS 84 reference systems. Gravity anomalies calculated for the different reference systems at the local level reveal a minimum deviation for the WGS-84 reference, which is therefore the best formula of normal gravity in the territory.