The International GNSS Service (IGS) is a service of the International Association of Geodesy (IAG), officially established in August 1993 at the IUGG General Assembly in Beijing, China. It provides freely and openly available high-precision GNSS data and products. The foundation of the IGS is a global network of over 400 permanent, continuously operating, geodetic-quality stations tracking GPS (USA), GLONASS (Russia), Galileo (EU), BeiDou (China), QZSS (Japan), and regional SBAS systems.
Within the framework of the IERS, the IGS contributes to the realization and maintenance of the International Terrestrial Reference Frame (ITRF) and to the determination of Earth Orientation Parameters (EOPs).
