Numerical Investigation of Different Gravity Models in Orbit Propagation of Two Short CHAMP and GRACE-A Arcs

Dynamic orbit determination is based on the solution of the equation of motion and the accurate modeling of all forces acting on the satellite. The present contribution aims at investigating the role of a geopotential model which is used to evaluate the Earth’s gravitational component in the procedure of dynamic orbit determination. For this reason we focus on the results obtained from the use of different available Earth gravity models in orbit propagation of current Low Earth Orbiters (LEOs). The obtained short arcs are compared with the corresponding Rapid Science Orbit (RSO) datasets. For the contribution of the dynamic component the gravity models JGM-3, EGM96, EIGEN-CHAMP03S, EIGEN-GRACE02S, EIGEN-CG03C, EIGEN-GL04C, EIGEN-GL04S1, EGM2008 and EIGEN-5C are used, while for the RSO information data from the CHAMP (CHAllenging Mini-satellite Payload) and GRACE (Gravity Recovery And Climate Experiment) satellites are applied. Orbit propagation is based on numerical integration of the equation of motion according to the 7th order Runge–Kutta–Nyström method. Differences between the two orbit types attempt to indicate the band-limited behaviour of the Earth’s gravity model.