AN EVALUATION STUDY OF THE CORRECT COMPUTATIONAL APPROACH FOR THE CONVERSION OF GRAVIMETRIC DATA FROM ONE REFERENCE DATUM TO ANOTHER

Abstract

The major deficiencies besetting most gravimetric networks as a result of non-adherence to the use of the correct computational approach for the conversion of the gravity data from one reference datum to another are discussed. In order to evaluate the computational models developed for the correct conversion, a typical gravity network was used as a case study. Field observations were carried out at the same sites as had been used initially in observing the typical gravity network. Observations were tied to the nearby standard gravity network so as to calibrate and monitor the behaviour of the gravimeter used for the survey. Analysis of the data shows that there are flaws in the original data set. Typical values of corrections required at each site to convert the network to the IGSN 71 standard using the GRS 67 are obtained. Some recommendations that will aid the proper harmonisation of gravimetric data are given. It is concluded that gravimetric work of reasonable size should always be referred to a common datum via a standard reference gravity network. Whenever it is desirable to convert gravity data from one reference datum to another, the correct computational approach should be used.