Commission 1 – Reference Frames

President: Christopher Kotsakis (Greece)
Vice President: Jean-Paul Boy (France)

Terms of Reference

Reference systems and frames are of primary importance for Earth science based research and applications, satellite navigation and orbit determination as well as for practical applications in positioning, mapping and geo-information related fields. A precisely defined reference frame is needed for an improved understanding of the Earth system, including its rotation and gravity field, sea level change with time, tectonic plate motion and deformation, glacial isostatic adjustment, geocentre motion, deformation due to earthquakes, local subsidence, and other crustal displacements. Commission 1 activities and objectives deal with the theoretical and operational aspects of how best to define reference systems and how reference systems can be used for practical and scientific applications at different spatio-temporal scales on the deformable Earth. Commission 1 will closely interact with the other IAG Commissions and Services, the ICCT, the newly established ICCC, and the GGOS components where reference system aspects are of concern, to address related problems for the realization of celestial and terrestrial reference systems in conformity with present and future accuracy needs. Commission 1 is also linked with the IUGG/COSPAR joint Sub-Commission B2 (International Coordination of Space Techniques for Geodesy) under the aim to develop links and coordinate the work between various groups engaged in the field of space geodesy and geodynamics.


The main objectives of Commission 1 are as listed in the IAG by-laws:

  • Definition, establishment, maintenance and improvement of the geodetic reference frames;
  • Advanced terrestrial and space observation technique development for the above purposes;
  • nternational collaboration for the definition and deployment of networks of terrestrially-
  • based space geodetic observatories;
  • Theory and coordination of astrometric observation for reference frame purposes;
  • Collaboration with space geodesy/reference frame related international services, agencies and organizations;
  • Promote the definition and establishment of vertical reference systems at global level, considering the advances in the regional sub-commissions;
  • Work to maintain a reference frame that is valuable for global change studies.

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