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Regional Models

Great Britain (OSGM15)

  Authors: Ordnance Survey and LPS     Created: 2015    Resp: C. Fane  
      Status: PUBLIC    
The OSGM15 model is a hybrid geoid derived from precise gravity surveys across UK, Ireland, and surrounding waters; additionally, the model includes data from the global geopotential model (EGM96) and the GRACE gravity mission (GGM02). A spherical FFT approach with modified Stokes kernels is used for the computation of the gravimetric geoid. Then the alignment to each regional vertical datum is based on precise GNSS observations at bench marks. Within Great Britain these include the Ordnance Survey fundamental bench mark (FBM) network. The resulting hybrid geoids are referred to ETRS89. The estimated accuracy is of 1 cm rms for Mainland GB, Outer Hebrides and Scilly Isles, 2 cm for Orkney and Shetland, and 3 cm for Isle of Man, while it is 2.3 cm std for Republic of Ireland and 1.4 cm std for Northern Ireland.

M. Greaves, P. Downie, K. Fitzpatrick (2016). OSGM15 and OSTN15: Updated transformations for UK and Ireland. Geomatics World, July/August 2016, pp. 18-21.

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Great Britain (OSGM15)