Global Gravity Field Models from different GOCE Orbit Products

Abstract

With GOCE, for the first time in history, a Gravity Gradiometer has been used in space to recover the Earth’s gravity field. Based on the gravity gradiometer observations, the short wavelength part of the Earth gravity field can be determined accurately. The lower frequency part (i.e. the long wavelength) of the Earth gravity field can be extracted from high-low Satellite to Satellite Tracking (hl-SST) data which are observed by the GNSS receiver onboard GOCE. Based on the high-low SST observations, kinematical precise orbit of GOCE can be determined. The kinematical precise orbit of GOCE, which either is estimated with an in-house developed software or supplied as the precise science orbit (PSO) by the European Space Agency (ESA), are used to estimate the Earth gravity field. The physical model of the applied gravity field recovery technique is based on Newton’s equation of motion, formulated as a boundary value problem in the form of a Fredholm's type integral equation. In this paper, the precise orbit product of the GOCE will be validated and the amount of gravity field information within the different orbit products will be compared in a validation step.