Global Unification of Height Systems and GOCE

Abstract

Two alternative approaches are available for the global unification of height systems. Either one connects the datum points, usually associated to tide gauges, directly by ocean levelling or indirectly by a combination of space positioning, geodetic levelling and the solution of a modified version of the geodetic boundary value problem (GBVP). In both cases a significant improvement will result from the gravity and geoid model produced by the Gravity and steady-state Ocean Circulation Explorer (GOCE) mission of ESA. For the direct method the GOCE-geoid will be combined with satellite altimetry to give a global map of dynamic ocean topography, for the indirect method it serves the computation of reference geoid height differences. In both cases the off-sets between height datums will become estimable with a precision of a few centimetres.