International Association of Geodesy

  International Earth Rotation and Reference Systems Service IERS
Chair: Jan Vondrak



The IERS is a service under the Federation of Astronomical and Geophysical Data Analysis Services (FAGS) and established by the International Astronomical Union and the International Union of Geodesy and Geophysics. 

Directing Board

Jan Vondrak (Chair), Bernd Richter (Central Bureau), Markus Rothacher, Daniel Gambis, William Wooden, Dennis D. McCarthy, Jean Souchay, Claude Boucher, Benjamin F. Chao, Sheng Yuan Zhu, Carine Bruyninx, Ron Noomen, Chopo Ma, Pascal Willis, Clark R. Wilson, David Pugh, Axel Nothnagel, Gerd Gendt, Peter Shelus, and Bob Schutz.

Terms of Reference 

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 modeling earth rotation/orientation;
  • Monitoring and modeling 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. 


Structure

The IERS accomplishes its mission through the following components: 

  • Technique Centers; 
  • Product Centers;
  • Combination Center(s);
  • Analysis Coordinator;
  • Central Bureau;
  • Directing Board;
  • Working Groups.

 
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).

For further information see other components of IAG.

Activity Report for 1999-2000 of the International Earth Rotation Service (IERS)
Activity Report for 1999-2003 of the International Earth Rotation Service (IERS)