Modeling gravity gradient data for gravity gradient aided navigation system

Nowadays, a completely self contained, passive navigation system that relies on gravity gradient instrument for INS aiding within non-GNSS(Global Navigation Satellite System) environments has been widespread concern. In order to research this system, a high accuracy and resolution gravity gradient data is what you should first gain. This paper presents the model used to simulate the gravity gradient for this passive navigation system. First describe how the gravity gradient is typically modeled using spherical harmonic and local terrain models. Then we will combine these two models to gain a more realistic representation of the earth´s gravity gradient. To verify the gradient modeling techniques and obtain the performance in different scenarios, we choose two different terrain variation areas and do the simulation respectively. High resolution full-tensor disturbance gradient data in these two areas were gained. Simulation test show that the method is feasible and effective.