NASA NASA Science GSFC Science Directorate GSFC Geodesy and Geophysics Laboratory (61A) International Association of Geodesy (IAG) Global Geodetic Observing System (GGOS) International Center for Earth Tides (ICET) International Centre for Global Earth Models (ICGEM) International DEM Service (IDEMS) International DORIS Service (IDS) International Earth Rotation and Reference Systems Service (IERS) International Service for the Geoid International GNSS Service (IGS) International Gravity Field Service (IGFS) International Laser Ranging Service (ILRS) International Terrestrial Reference Frame (ITRF) International VLBI Service for Geodesy and Astrometry (IVS) Permanent Service for Mean Sea Level (PMSL) Time Section of the International Bureau of Weights and Measures (BIPM) Other Norwegian Mapping Authority MIT Haystack Observatory
