The Global Positioning System (GPS) Analysis Program produces high-quality estimates of polar motion and UT1-like variations, GPS satellite orbits, clocks for the tracking station and satellites, and other quantities from observations of the GPS satellites. This work is done in close conjunction with the International GNSS Service (IGS) and relies upon the IGS global tracking network. The IGS polar motion results dominate in the IERS Bulletin A combination due to their high accuracy, reliability, and rapid availability. The GPS-based UT1-like results, while lacking a direct or absolute link to the celestial reference frame, are very useful for interpolating UT1 information when none is available from VLBI and for extrapolating to the most recent times after the latest VLBI observing session.
Together with several other Analysis Centers, the Earth Orientation Department serves as an IGS Analysis Center. As such, orbit, clock, and EOP estimates and predictions are submitted multiple times per day to the IGS Analysis Center Coordinator for combination into the IGS Rapid and IGS Ultra products. In addition, daily troposphere estimates are submitted as the IGS Final Troposphere product. To obtain these results, please refer to the IGS Data and Products web site. A summary of current analysis procedures is also available.