Transverse thematic action SI-GNSS – GNSS information system


The ATT SI-GNSS brings together several French GNSS networks or observation systems, including those of the AS members of the GT Géodésie GNSS. It aims to federate these networks or observation systems to develop common GNSS data and metadata dissemination systems, and manages the resulting dissemination infrastructure.

At the launch of the Epos-France IR, the most advanced common dissemination system set up as part of the ATT SI-GNSS is the system developed as part of the European Epos-GNSS infrastructure. The ATT SI-GNSS is involved in its implementation at European level, building a node architecture (thematic, national and European portal) and managing these different nodes. By 2023, this infrastructure will be the main data distribution system for the permanent SNO Rénag and SNO Volcanologie GNSS networks. The French GNSS data produced by the partners in the ATT SI-GNSS will be integrated in full or, depending on the conditions imposed or for technical reasons, only partially. For the latter, other solutions will have to be considered.

The partners of the ATT SI-GNSS are :

  • Permanent national GNSS network – AS Rénag
  • SNOV permanent GNSS networks
  • RGP (AS RGP)
  • SONEL system data center
  • REGINA (for Europe stations)
  • GPSmob (AS GPSmob)

The SI-GNSS Transverse Action is attached to the Epos-France GNSS Geodesy Thematic Group.


The ATT SI-GNSS aims to federate the distribution of GNSS data from multiple organizations, to find the minimum number of solutions and to promote data visibility through the IR EPOS-France. Each partner retains its independence and autonomy to carry out the missions dictated by its reference institution(s), and can thus maintain, in parallel, its own distribution infrastructure, best meeting the needs of its specific users.

The main objectives of the SI-GNSS transverse thematic action are to ensure the continuity of GNSS observations produced by the academic community and its partners, to distribute them to as many people as possible, and to ensure their quality and reusability, particularly for academic research purposes.

Research topics that can benefit from these data include, but are not limited to: measurement of tectonic and volcanic deformations, sea level measurement, measurement of the water vapor content of the troposphere, measurement of overloads associated with oceans, the atmosphere or hydrological loads in general, measurement of the electronic content of the ionosphere, or the creation of a geodetic reference frame.

In brief

  • Thematic Group: geodesy GNSS
  • Type: Système d’information
  • Supervisor and web contact:  Mathilde Vergnolle, OCA (Géoazur)
  • Participating partners: CNES, DT CNRS-Insu, IGN, IPGP, OCA
  • Other participants: ENS, OASU,  Oreme, OSUL