Error Analyses for a Gravity Gradiometer Mission

This paper addresses the usefulness of an orbiting gravity gradiometer as a sensor for mapping the fine structure of the Earth gravity field. The exact knowledge of this field is essential for studies of the solid Earth and the dynamics of the oceans. Although the Earth gravity tensor, measured by a gradiometer assembly, has nine components, only five components are independent. This latter fact is as a consequence of the symmetry and conservative nature of the Earth's gravity field. The most dominant component is the radial one. The error analyses considered here are therefore based only upon a single axis gradiometer sensing this radial component. The expected global gravity and geoid errors for a 50 x 50-km (1/2° x 1/2°) area utilizing a space-borne gradiometer with a precision of 10-3 EU in a 160-km circular polar orbit are about 3 mGAL and 5 cm, respectively.