Modelling the vertical gravity gradient for gravity measurements reduction

Abstract

When establishing the gravity network, precise values of the vertical gravity gradient are needed to reduce measurements at the level of benchmarks. As the determination of the gradient is time-consuming and expensive, this article presents the first effort of modelling it within the scope of the new French gravity network. Some existing mathe-matical models based upon derivation of geoid undulation or gravity anomalies integration are listed and commented. Variants using terrain information are also tested. Gradients measured and modelled by several methods are compared, leading to a standard deviation of the differences of 14.5x$10^{-8}S^{-2}$ 145(E)with the best method.