Director
Geodion Ltd
Nadim Dayoub is a geodesist with a PhD in Physical Geodesy from Newcastle University and over 20 years of experience in GNSS positioning, satellite altimetry, gravity-field modelling, geoid computation, and geodetic reference systems. His research includes contributions to the determination of the Gauss–Listing geopotential value W0 and its role in global height reference systems. He has worked across academic research, Earth observation, offshore positioning, and geospatial engineering, and currently focuses on updated W0 realisations and best-fitting reference ellipsoids for modern reference systems.
Datum
This presentation introduces an updated determination of the Gauss–Listing geopotential value W0, a fundamental quantity for the realisation of global vertical reference systems and modern height datums. The study revisits earlier methodology using contemporary global datasets, including recent mean sea surface models, ocean dynamic topography information, and a high-resolution global gravity field model, all treated consistently within the same tide system.
An independent normal-gravity formulation is also used to define a new best-fitting global reference ellipsoid satisfying U0 = W0 The presentation discusses how the updated W0 realisation and associated ellipsoid contribute to a physically consistent reference surface for geoid computation, gravity-field modelling, and the unification of vertical height systems.