Science Background
Earth Rotation
The parameters to describe the Earth's rotation and how its irregularities are measured.
The ICRS
The International Celestial Reference System and its realization, the International Celestial Reference Frame.
The ITRS
The International Terrestrial Reference System and its realization, the International Terrestrial Reference Frame.
Recommendations
IAU and IUGG resolutions and recommendations on reference systems and on the IERS.
Observation techniques
The observation techniques for earth rotation and reference systems: GPS, SLR, LLR, VLBI, and DORIS.
References
Publications on earth rotation, reference systems, geophysical fluids and on the IERS.