ERP

Earth Rotation Parameters (ERP) files

Earth Rotation Parameters (ERPs) are the key conversion parameters between the International Terrestrial Reference Frame (ITRF) and International Celestial Reference Frame (ICRF). ERP files provide information on the variations in the Earth’s rotation rate, i.e., universal time (UT1-UTC) or length of day (LOD); as well as on the variations in the position of the Earth’s axis, i.e., the polar motion (PMX, PMY).