U.S. Naval Observatory | Earth Orientation Department |
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The IERS Rapid Service/Prediction Center is the product center of the International Earth Rotation and Reference Systems Service responsible for providing Earth orientation parameters (EOPs) on a rapid turnaround basis. This service is primarily intended for real-time users and others needing the highest quality EOP information sooner than is available in the IERS final series (Bulletin B) published by the IERS Earth Orientation Center, which is based at the Observatoire de Paris. |
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This Center is an activity of the Earth Orientation (EO) Department at the U.S. Naval Observatory (USNO). The mission of the USNO includes determining the positions and motions of celestial bodies, measuring the Earth's rotation and orientation, maintaining the master clock for the U.S., and disseminating precise time (atomic and astronomical). The EO Dept. contributes to this mission by collecting suitable observations and performing data analyses to determine and predict the time-varying orientation of the terrestrial reference frame within the quasi-inertial celestial reference frame. The key parameters determined and disseminated are polar motion coordinates, Universal Time (UT1), precession, and nutation. The user community is very broadly based, the main applications involving principally high-accuracy navigation and positioning, particularly in real-time and near real-time modes. |
2004 IERS Bulletin A Vol. XVII Website
Bulletin A now contains dX & dY with respect to IAU2000A Nutation/Precession
General Information about Earth Orientation
The last leap second was positive and was introduced in UTC at the end of December 1998.
No leap second was introduced at the end of December 2003.
(see IERS Bulletin C 23)
IERS Bulletin A -- Rapid
Service/Prediction of Earth Orientation
Additional information concerning IERS Bulletin A:
Publications about IERS Bulletin A:
Standard data files available by anonymous ftp -- now updated weekly (Thursday), prior to 1 July 2002 (Tuesday and Thursday):
Daily data files available by anonymous ftp -- updated daily (normally about 17:05 UTC), for highest accuracy real-time applications
Discontinued data files -- no longer available:
IERS Bulletin B ("Final" EOP values)
IERS Bulletin C (Leap Second Announcements)
IERS Bulletin D (Announcements of DUT1)
General Publications
Document Request Form
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U.S. Naval Observtory, EO Dept. Attn: ser7 | |
3450 Massachusetts Avenue NW | |
Washington, DC 20392-5420 | last updated 21 Jul 2004 |