IERS Rapid Service / Prediction Center

The IERS Rapid Service/Prediction Center (RS/PC) is a product center of the International Earth Rotation and Reference Systems Service (IERS), responsible for providing daily Earth Orientation Parameters (EOPs) to the International community.

This service is primarily intended for real-time users and others needing the highest quality EOP information prior to the availability of the IERS final series, Bulletin B, published by the IERS Earth Orientation Center based at the Observatoire de Paris.

The RS/PC 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 Earth Orientation Department 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), and celestial pole offsets (also known as nutation offsets). 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.