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Regional Models

Great Britain (OSGM02)


  Authors: J.C. Iliffe, et al.     Created: 2002    Resp: C. Fane  
      Status: PUBLIC    
Description:
The OSGM02 model is a hybrid geoid covering all the land areas and inshore waters of the United Kingdom, the Republic of Ireland and the Isle of Man. A gravimetric geoid model has been computed by spherical FFT in the framework of a remove-restore technique, using gravity data spaced approximately at 1.5 km, EGM96 as reference global model and 100 m spaced DEM data. The gravimetric geoid was computed rigorously as a quasi-geoid, then converted to a classical geoid consistent with the use of Helmert orthometric heights. After that the gravimetric model has been fitted to GPS/levelling data by least-squares collocation. The fitting has been performed over patches corresponding to the different vertical datums (Newlyn, Malin Head, Belfast and minor island datums). The resulting hybrid geoids are referred to ETRS89. The overall error of the patched final OSGM02 geoid surface is estimated at 2 cm r.m.s. in the UK and 3-4 cm r.m.s. in other areas.


References:
J.C. Iliffe, M. Ziebart, P.A. Cross, R. Forsberg, G. Strykowski, C.C. Tscherning (2003). OSGM02: A new model for converting GPS-derived heights to local height datums in Great Britain and Ireland. Survey Review, 37(290), pp. 276-293.

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