GGOs

Global Geodetic Observing System (GGOS) is an international framework established by the International Association of Geodesy (IAG) to coordinate geodetic observations and information. Its aim is to provide a consistent, accurate, and sustainable view of the Earth’s geometry, gravity field, and rotation, through integrated observations and data products.

GGOS seeks to unify the world’s geodetic networks and data streams to produce long-term, stable reference frames and Earth orientation parameters that support monitoring of Earth system changes. This includes applications such as plate tectonics, sea level rise, mass redistribution, and climate-related processes, as well as navigation, surveying, and geodetic research.

The GGOS structure rests on three pillars. The observing system brings together space-based and terrestrial measurement techniques, notably the main geodetic methods: GNSS (Global Navigation Satellite System), SLR (Satellite Laser Ranging), VLBI (Very Long Baseline Interferometry), and DORIS, along with gravity field and altimetry data from dedicated missions. The data, standards, and products pillar covers data management, metadata and quality control, archiving, and the production of key products such as the International Terrestrial Reference Frame (ITRF) and Earth Orientation Parameters (EOP). The infrastructure pillar ensures the sustained operation and accessibility of data and products, including governance, regional networks, and agreed procedures.

GGOS is implemented under the IAG with participation from major space agencies, national geodetic institutes, and international organizations. Its outputs underpin scientific research in geodesy, geophysics, and climate science, and support precise navigation, hazard assessment, and policy-relevant monitoring of Earth changes.