Chapter 4: Terrestrial reference sytems and frames

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All content in the updated pages should be considered under development and are not definitive nor officially approved as a registered edition. For the official IERS Conventions (2010), please download the packaged v 1.0.0.


  • 1 April 2019:
    • Chapter 4 has been re-written to accommodate the following updates:
      • A description of ITRF2014, with its associated equations, to model the nonlinear station motions due to seasonal signals and post-seismic deformation of stations subject to major earthquakes.
      • A description of the mathematical model used in the ITRF combination.
      • A revision of Table 4.1, listing the transformation parameters relating ITRF2014 to previous ITRFs.
      • Improvements in wording and the removal of unnecessary paragraphs.


  • GCONV2.F - Transforms from cartesian to geographic coordinates

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