World Geodetic Datum 2000

  • E. W. Grafarend
  • A. A. Ardalan
Conference paper
Part of the International Association of Geodesy Symposia book series (IAG SYMPOSIA, volume 120)


Based on the current best estimates of the fundamental geodetic parameters, i.e., W 0 (Grafarend and Ardalan, Journal of Geodesy 71 (1997) 673-679), GM (Ries et al, Geophys. Res. Letters 19 (1992) 529-531), J 2 (Lemoine et al, GRAGEO-MAR 1996, International Association of Geodesy, Symposia 117, (1996) 461-469) and Ω (given in Internal Communications of IAG/IUGG Special Commission 3, Darmstadt (1997)), the form parameters of a Somigliana-Pizetti level ellipsoid, namely the semi-major axis a and semi-minor axis b (or equivalents the linear eccentricity ɛ = √a 2 - b 2 ) are computed. There are six parameters namely the four fundamental geodetic parameters {W 0 , GM, J 2 , Ω} and the two form parameters {a, b} or {a, ɛ}, which determine the ellipsoidal reference gravity field of Somigliana-Pizetti type constraint to two nonlinear condition equations. Their iterative solution leads to best estimates a = (6378136.572 ±0.053)m, b = (6356751.920 ±0.052)m, ɛ= (521853.580 ±0.013)m for the tide-free geoid of reference and a = (6378136.602 ±0.053)m, b = (6356751.860 ± 0.052)m, ɛ= (521854.674 ±0.015)m for the zero-frequency tide geoid of reference. The best estimates of the form parameters of a Somigliana-Pizetti level ellipsoid, {a, b}, differ significantly by -0.398m, -0.454m, respectively, from the data of the Geodetic Reference System 1980.


Form Parameter Geodetic Reference System Error Propagation Relation Level Ellipsoid Stud Geoph Geod 
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Copyright information

© Springer-Verlag Berlin · Heidelberg 2000

Authors and Affiliations

  • E. W. Grafarend
    • 1
  • A. A. Ardalan
    • 1
  1. 1.Department of Geodesy and GeoinformaticsStuttgart UniversityStuttgartGermany

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