Test of GPS on the CERN-LEP Control Network

des Instituts für Geodäsie

Heft 20-2/1985

Test of GPS on the CERN-LEP Control Network

European Organization for Nuclear Research - CERN,
Geneva / Switzerland

Gerhard BEUTLER / Werner GURTNER
University of Bern / Switzerland


In: WELSCH, Walter M. / LAPINE, Lewis A. (Hrsg.) [1985]:
International Federation of Surveyors - FIG -
Proceedings Inertial, Doppler and GPS Measurements for National and Engineering Surveys
Joint Meeting of Study Groups 5B and 5C, July 1-3, 1985

Schriftenreihe Universitärer Studiengang Vermessungswesen, Universität der Bundeswehr München, Heft 20-2, Neubiberg, S. 337-358.


The installation and the alignment of a particle accelerator require a very high accuracy. For the new CERN project, the Large Electron Positron ring (LEP) fo 27 km circumference, a reliable control network has been created. Measurements have been made with the two-colour Terrameter, giving an accuracy of 10-7, and precision levelling. Computations took into account a very fine assessment of the Geoid, through collocation on a large mass model and astro-geodetic measurements with a zenithal camera. Resulting local coordinates were good to σ ≤ 1.5 mm for planimetry and σ < 5 mm for altimetry above a local ellipsoid.

In December 1984, seven points of this network were observed using GPS (Global Positioning System) satellite receivers. The measurements were carried out by GEO-HYDRO Inc. with three Macrometer V-1000 Surveyor instruments. Six independent baselines of this GPS network were measured twice during three consecutive days. Although the observation (with the Bernese GPS Software Package) gave rms-errors of roughly 1 - 2 mm per coordinate, showing an excellent internal consistency of the GPS solution. The comparison with the terrestrial solution was established through a Helmert-transformation. The overall rms error of the transformation is 4 mm.

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