The Role of Position Information for the Analysis of K-Band Data: Experiences from GRACE and GOCE for GRAIL Gravity Field Recovery

Abstract

The Gravity Recovery And Interior Laboratory (GRAIL) mission orbiting the Moon and the Gravity Recovery And Climate Experiment (GRACE) mission orbiting the Earth share many conceptual commonalities. Major differences reside, however, in the absolute positioning of the spacecraft, which is accomplished by Doppler tracking from NASA’s Deep Space Network (DSN) for GRAIL and by the Global Positioning System (GPS) for GRACE. Data from GRACE and from the Gravity and steady-state Ocean Circulation Explorer (GOCE) are used to investigate the role of position information. Artificially degrading either the geographical coverage or the accuracy of kinematic positions serving as input data together with continuously available K-Band inter-satellite data is shown not to be a limiting factor for gravity field recovery using the Celestial Mechanics Approach (CMA). Eventually, the CMA is applied to Level-1B data of the GRAIL mission to derive first Bernese lunar gravity field solutions.