Interpolating Surface Gravity Data for Assessing the Accuracy of a Ground Inertial Navigation System/Global Positioning System Gravimetric System

Abstract

High-resolution gravity data are efficiently collected by using a ground-vehicle-based inertial navigation system/global positioning system (INS/GPS) gravimetric system due to its closeness to the terrain and relatively speedy process. Previous studies have shown that this system has better than 1 mGal repeatability. However, the validation of the absolute precision is limited by the availability of ground control data and the selected interpolation method. Careful comparisons of the gravity estimates with independent ground control are necessary to arrive at a better knowledge of the system’s precision. First, several interpolation schemes are designed to interpolate the control data to known values along the ground tracks. The computation results show that the least square collocation method provides the most accurate interpolates of the surface data set, while the three-dimensional multi-quadrics method works well after applying the terrain correction. The best-estimated control data used have better than 3 mGal precision agreement with the wave-correlated gravity estimates obtained at the tracks of the INS/GPS gravimetric system.