World Height System Definition and Implementation
Final rept. 9 Sep 1992-11 Dec 1993
OHIO STATE UNIV COLUMBUS DEPT OF GEODETIC SCIENCE AND SURVEYING
Pagination or Media Count:
Height systems of the world are inconsistent at the or - 1 m level of accuracy. This report discusses two procedures that attempt to determine an ideal equipotential surface for heights and the connection of regional vertical datums. One method uses 18 stations whose precise geocentric coordinates are known along with the orthometric or mean sea level height with respect to a regional vertical datum. This information is combined with gravity data for geoid undulation determination in a general least squares adjustment. The results include the separation between a reference ellipsoid and the ideal geoid surface as well as the connection of the regional datums to the geoid. One finds, for example, the origin of the NAVD88 system U.S. is 40 or - 4 cm below the geoid while the ODN Newlyn England is 26 or - 23 cm below the geoid. A second procedure to examine the difference between vertical datums used Doppler positioned stations on various vertical drums. Using a degree 360 potential coefficient model, for geoid undulation determination, the separation between several datums was determined. For example, the NN datum used in Germany appears to be 91 cm higher than the reference surface of the ODN Newlyn datum used in England. The methods and results described in this report form a foundation for the development of a world height system.