Density compensation to reference map of gravity navigation

The current method of gravity gradient maps modeling is based on digital elevation model, the effects of isostasy in gravity gradient map modeling are researched and analyzed in this paper, and a novel method of modeling gravity gradient maps was presented. The current isostasy theory shows that the density of crust changes with elevation, so assigning a constant value to terrain´s density is not accurate enough. At first, two kinds of isostasy model are analyzed, and on the basis of isostasy model, the gravity gradient map is modeled by using improved terrain density model. Then experimental results shows that Pratt model impose much more effects on gravity gradient map than Airy model. Consider the two models´ effects in gravity gradient map modeling, Pratt Model has a great performance in the sea area, and Airy Model can be ignored the impact in the land area.