GrazLGM300a - an improved lunar gravity field model using the short-arc integral equation technique

Abstract:

We present an updated version of the lunar gravity field model GrazLGM200a (Klinger et al. 2014; doi: 10.1016/j.pss.2013.12.001) derived from inter-satellite observations collected by the Gravity Recovery And Interior Laboratory (GRAIL) mission. We exploit the ranging measurements by an integral equation approach using short orbital arcs. The basic idea of the technique is to reformulate Newton's equation of motion as a boundary value problem. This method has already been successfully applied for the recovery of the Earth's gravity field from data provided by the Gravity Recovery And Climate Experiment (GRACE) project. For the compilation of our new Graz Lunar Gravity Model, GrazLGM300a, we refined modeling and parameterization. Particular attention is paid to processing details associated with the error structure of the observations (covariance functions) and the incorporation of non-gravitational forces acting on the spacecraft. We validate our results against recent GRAIL models computed at NASA-GSFC and NASA-JPL.