Frank G. Lemoine coauthored a high-resolution lunar gravity solution from GRAIL spacecraft tracking. The GRGM900C model represents the field using spherical harmonics and compares it with the gravity predicted from lunar surface topography.[ref]
GRGM900C: A degree 900 lunar gravity model from GRAIL primary and extended mission data by Frank G. Lemoine and others. Abstract and sections 4.2–4.3: tracking solution and gravity/topography comparison
Higher harmonic degree resolves shorter spatial scales, but useful resolution also depends on orbit geometry and measurement uncertainty. Residual gravity after topographic correction helps investigate subsurface density structure.
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