Modeling and analysis of gravity and gravity gradient based on terrain anomaly

Gravity map or gravity gradient map is one of three elements of aided navigation based on the gravity field. The characteristics of the gravity map or gravity gradient map is one of the keys to gravity field aided navigation. In this paper, the integral range is determined under the condition of guaranteeing accuracy, the gravity map and gravity gradient map are calculated by the terrain anomaly body, and the statistical characteristics of gravity map and gravity gradient map at different grid spacing are analyzed. The simulation results show that the gravity gradient contains more high frequency information, and the gravity map contains more low frequency information in the same grid spacing. When the grid spacing is 50m, 100m and 200m, the variation of the standard deviation of gravity gradient is less than 1E, when the spacing is 400m, the variation of the standard deviation of gravity gradient is greater than 1E. If the accuracy of gravity gradiometer is less than 1E, the accuracy of navigation by gravity gradient under this terrain is less than 200m. When the grid spacing is 50m, 100m, 200m, 400m, the change of gravity standard deviation is less than 0.2mGal. If the accuracy of the gravimeter is less than 0.2mGal, the accuracy of navigation by gravity under this terrain is less than 400m.