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International Earth Rotation and Reference Systems Service (IERS)


Chair of the Directing Board: Brian Luzum (USA) 
Director of the Central Bureau: Daniela Thaller (Germany)


The IERS was established as the International Earth Rotation Service in 1987 by the International Astronomical Union and the International Union of Geodesy and Geophysics, and it began operation on 1 January 1988. Since 2001, the IERS works in a new organizational structure; in 2003, the new name of the Service, without changing its abbreviation, was adopted. The IERS is a member of the Federation of Astronomical and Geophysical Data Analysis Services (FAGS).

see also: http://www.iers.org/IERS/EN/Organization/About/History/history.html


The primary objectives of the IERS are to serve the astronomical, geodetic and geophysical communities by providing the following:

  • The International Celestial Reference System (ICRS) and its realization, the International Celestial Reference Frame (ICRF)
  • The International Terrestrial Reference System (ITRS) and its realization, the International Terrestrial Reference Frame (ITRF)
  • Earth orientation parameters required to study earth orientation variations and to transform between the ICRF and the ITRF
  • Geophysical data to interpret time/space variations in the ICRF, ITRF or earth orientation parameters, and model such variations
  • Standards, constants and models (i.e., conventions) encouraging international adherence



IERS collects, archives and distributes products to satisfy the objectives of a wide range of applications, research and experimentation. These products include the following:

  • International Celestial Reference Frame
  • International Terrestrial Reference Frame
  • Monthly earth orientation data
  • Daily rapid service estimates of near real-time earth orientation data and their predictions
  • Announcements of the differences between astronomical and civil time for time distribution by radio stations
  • Leap second announcements
  • Products related to global geophysical fluids such as mass and angular momentum distribution
  • Annual report and technical notes on conventions and other topics
  • Long-term earth orientation information


The accuracies of these products are sufficient to support current scientific and technical objectives including the following:

  • Fundamental astronomical and geodetic reference systems
  • Monitoring and modelling earth rotation/orientation
  • Monitoring and modelling deformations of the solid earth
  • Monitoring mass variations in the geophysical fluids, including the atmosphere and the hydrosphere
  • Artificial satellite orbit determination
  • Geophysical and atmospheric research, studies of dynamical interactions between geophysical fluids and the solid earth
  • Space navigation.

see also: http://www.iers.org/IERS/EN/DataProducts/data.html



The IERS accomplishes its mission through the following components:

  • Technique Centers: International GNSS Service, International Laser Ranging Service, International VLBI Service, and International DORIS Service
  • Product Centers: Earth Orientation Center, Rapid Service/Prediction Center, Conventions Center, ICRS Center, ITRS Center, and Global Geophysical Fluids Center with Special Bureaus for the Atmosphere, for the Oceans, for Tides, for Hydrology, for Mantle, for the Core, for Gravity/Geocentre, and for Loading
  • ITRS Combination Centers at Deutsches Geodätisches Forschungsinstitut (DGFI), Geomatics Canada/Geodetic Survey Division, Institut Géographique National (IGN)
  • Combination Research Centers at Agenzia Spaziale Italiana (ASI), Astronomical Institute, Academy of Sciences of the Czech Republic, and Department of Geodesy, Czech Technical University, Prague, Deutsches Geodätisches Forschungsinstitut (DGFI), Forsvarets forskningsinstitutt (FFI, Norwegian Defence Research Establishment), GeoForschungsZentrum Potsdam (GFZ), Geodätisches Institut der Universität Bonn (GIUB), Groupe de Recherches de Géodésie Spatiale (GRGS), Institut Géographique National (IGN), Ecole Nationale des Sciences Géographiques (ENSG), Laboratoire de Recherche en Géodésie (LAREG), Jet Propulsion Laboratory (JPL)
  • Analysis Coordinator
  • Central Bureau
  • Directing Board
  • Working Groups: WG on Combination, WG on Prediction, IERS/IVS WG on the Second Realization of the ICRF.

Some of these components (e.g., Technique Centers) may be autonomous operations, structurally independent from IERS, but which cooperate with the IERS. A participating organization may also function as one or several of these components (except as a Directing Board).

see also: http://www.iers.org/IERS/EN/Organization/organization.html


IERS Directing Board

visit the IERS homepage for a list of current members

Content of this contribution provided by Bernd Richter.

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