The **International Earth Rotation and Reference Systems Service (IERS)**, established in 1987 by the International Astronomical Union (IAU) and the International Union of Geodesy and Geophysics (IUGG), is a global scientific organization dedicated to providing precise data and standards on Earth rotation and reference frames essential for astronomy, geodesy, and geophysics[1][2][3][6]. It began operations on January 1, 1988, replacing earlier services like the International Polar Motion Service and the Earth Rotation Section of the Bureau International de l’Heure. In 2003, the organization adopted its current name to better reflect its expanded responsibilities[3]. IERS provides the **International Celestial Reference System (ICRS)** and its realization, the **International Celestial Reference Frame (ICRF)**, as well as the **International Terrestrial Reference System (ITRS)** and its realization, the **International Terrestrial Reference Frame (ITRF)**. These reference frames are fundamental for accurately determining Earth orientation parameters (EOP), which describe Earth's rotation and orientation changes in space and link the celestial and terrestrial coordinate systems[2][3]. Such data enable precise satellite navigation, space missions, and Earth observation technologies. A key role of IERS is maintaining global standards and conventions to ensure international consistency in measurements and models related to Earth rotation, geophysical variations, and timekeeping, including leap seconds. It serves as a scientific service under the International Association of Geodesy (IAG) and is a member of bodies like the International Committee on Global Navigation Satellite Systems (ICG)[2][6]. IERS collaborates with autonomous technical centers such as IDS, IGS, ILRS, and IVS, and institutions like the GFZ Potsdam, contributing to the Global Geophysical Fluid Center. It also manages precise local tie surveys at co-location sites worldwide to enhance reference frame accuracy[1][5]. Notably,