Test of GOCE EGG data for spacecraft positioning

Abstract : Consisting of three pairs of accelerometers, the gradiometer is an ideal sensor for passive navigation. This paper proposes the use of gravity gradients for spacecraft positioning and the real-world GOCE EGG data are tested to investigate the feasibility. The basic observation equation is first formulated by considering white noise only, and a Least-Square position searching method is developed. The raw GGT measurements are preprocessed before the test in order to remove the low-frequency errors. By using a 120-degree EGM2008 gravity model as a reference map, position solutions with an accuracy of hundreds of meters are obtained. A further semi-simulation study shows that an accuracy of tens of meters could be achieved with a better gradiometer.