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Definition of a Terrestrial Reference Frame using IRIS VLBI Observations; Approaching Millimeter Accuracy

  • W. E. Carter
  • D. S. Robertson
Part of the International Association of Geodesy Symposia book series (IAG SYMPOSIA, volume 105)

Abstract

The data now available from space-based geodetic observing techniques, especially Very- Long-Baseline Interferometry and Satellite Laser ranging, presently allow us to define a terrestrial reference frame with an accuracy of better than two centimeters. Improvements to the observing systems over the next few years may allow accuracies approaching a few millimeters. These unprecedented accuracy levels raise a number of interesting technical and scientific questions concerning the accuracy of the Earth models used to reduce the data. For example, observations of the changes in the lengths of baselines from North America to Europe show 25 to 30% discrepancies from the values given by the Minster- Jordan AMO-2 plate motion model, which is now uniformly adopted for processing the new data. Also, vertical crustal motions expected from glacial rebound not presently included in the data reduction can exceed 1 cm per year at some sites. Existing VLBI observing networks lack the global coverage necessary to realize the potential of the present accuracy levels. In the next few years much effort will need to be directed toward establishing observatories in under-represented portions of the globe, especially the southern hemisphere and the central Asia-Indian ocean regions.

Keywords

Global Position System Terrestrial Reference Frame VLBI Observation Vertical Crustal Motion National Geodetic Survey 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag New York Inc. 1990

Authors and Affiliations

  • W. E. Carter
    • 1
  • D. S. Robertson
    • 1
  1. 1.National Geodetic Survey, Charting and Geodetic ServicesNational Ocean Service, NOAARockvilleUSA

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