[G02-4] Gravity field modelling and applications

[G02-4-01] NGS Annual GRAV-D enhanced Geoid Models – xGEID2017: What is new and the results

^○Yan Ming Wang¹, Simon Holmes², Xiaopeng Li³, Kevin Ahlgren¹ (1.National Oceanic and Atmospheric Administration, Silver Spring MD USA, 2.SGT Inc. Greenbelt MD USA, 3.DST Inc. Silver Spring MD USA)

The United States National Geodetic Survey [NGS] has been computing experimental gravimetric geoid models annually. For these models, the latest satellite gravity models are combined with terrestrial gravity data, and with airborne gravity data collected through the “Gravity for the Redefinition of the American Vertical Datum" [GRAV-D] effort over the USA and its territories. To date, over 50% of this area has been flown. Both the airborne and terrestrial gravity data are cleaned and their accuracies are estimated for combination in the least squares sense. This paper outlines the methods used for data cleaning, editing and error estimation, and the data combination. Results from using independent data sets to validate the geoid models are also presented.