In 2008, the National Geospatial-Intelligence Agency [NGA] officially released its latest Earth Gravity Model [EGM], designated Earth Gravitational Model 2008 [EGM2008]. EGM2008 is a state-of-the-art spherical harmonic model of the Earth's external gravitational field. It incorporates spherical coefficients for harmonic degrees 2 to 2190, which provide a nominal spatial resolution of approximately 9.3 km at the Equator. This means that EGM2008 (in conjunction with its ancillary topographic models and in regions where quality data was made available to the EGM2008 project) is the first global EGM capable of supporting geoidal (N) transformations between purely GPS-derived geodetic heights (h) and orthometric heights (H), without the need for augmentation from local high-resolution data. In comparisons with independent GPS/Leveling data, EGM2008 outperformed the aging gravimetric geoid models for Australia (AusGeoid98 - now 11 years old), and the USA (G99SSS - now 10 years old). Both AusGeoid98 and G99SSS are to be retired and replaced in 2009.

In the United States, the National Geodetic Survey [NGS] holds the official charter to maintain the vertical datum for the USA and its territories. This includes the responsibility to maintain a current geoid model for transforming between orthometric (H) and geodetic (h) heights. The new (2009) NGS geoid model will benefit greatly from the prior release of EGM2008, which served as a computational reference field for the new geoid, but was also particularly useful for identifying and removing corrupted data from the NGS gravimetry database. The new NGS geoid model will also incorporate: the latest GRACE-based satellite-only geopotential solutions; new aero-gravimetry, particularly along coastal regions; very-high-resolution digital elevation models [DEMs] derived from the Shuttle Radar Topography Mission [SRTM], and other additional data and processing improvements.

Looking forwards, NGS intends to increase its efforts to refine and improve its future national geoid models. To this end, their ambitious "Gravity for the Re-definition of the American Datum" [GRAV-D] project aims to update the NGS gravimetry holdings by flying new aero-gravity surveys over a large fraction of the USA and it territories. Concurrent efforts will focus on developing new processing techniques for optimally incorporating improved topographic, gravimetric and satellite data into the final geoid solution.