External validation of the GRACE GGM01C gravity field using GPS and DORIS positioning results

[1] We have used the new gravity field model GGM01C derived from GRACE data to reanalyze DORIS data from 1993.0 to 2003.2 using the Gipsy/Oasis software and a free-network approach. We have estimated the position and velocity of each DORIS station in ITRF2000. In order to test the accuracy of these results, we have compared them to the positions and velocities of 43 collocated GPS stations using local ties and covariance information. DORIS results computed using the GGM01C gravity field instead of the EGM96 gravity field show a significantly improved external agreement with GPS. Position agreement of 12–26 mm was reduced to 10–13 mm and velocity agreement of 3.3–3.7 mm/yr was reduced to 2.4–3.3 mm/yr. This can be interpreted as an external test of the accuracy of the new GGM01C gravity field.

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