On 31 October 2020, anonymous ftp access will officially be discontinued at CDDIS. Beginning October 1, 2020, CDDIS will bandwidth limit ALL IPs using anonymous ftp to just 50KB/s and will limit simultaneous downloads to only 3 per IP address. CDDIS is STRONGLY recommending all users begin to transition to using alternate method of access to the CDDIS archive. Examples of alternate methods can be found at: https://cddis.nasa.gov/Data_and_Derived_Products/CDDIS_Archive_Access.html.

close window
IERS Rapid Service/Prediction Center for Earth Orientation Parameters


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.


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.

IERS Rapid Service/Prediction Center files at CDDIS

The CDDIS is providing a backup mirror of the IERS Rapid Service / Prediction Center (RS/PC) daily and Bulletin A EOP solutions and other Earth orientation results. The starting directory for these files is:


Daily EOP solutions (including finals.daily, finals2000A.daily and gpsrapid.daily) should be uploaded here at 18:00 UTC each day, and Bulletin A EOP data should by available by 20:00 UTC on Thursdays. Three subdirectories, eop0300utc, eop0900utc, and eop2100utc, are updated daily with intermediate, sub-daily versions of these files, finals.daily, final2000A.daily, and gpsrapid.daily.

This backup mirror can be used in cases when the primary servers ftp://maia.usno.navy.mil/ser7, http://maia.usno.navy.mil/ser7, ftp://toshi.nofs.navy.mil/ser7, and http://toshi.nofs.navy.mil/ser7 are not accessible.

Contact information (USNO)