31 August 2020
The SNO includes 2 main components : 1) a contribution to international scientific services of IAG (International Association of Geodesy) including the Bureau Gravimétrique International (BGI) and the International Geodynamics and Earth Tide Service (IGETS), and 2) a contribution to the monitoring of temporal gravity variations performed from a set of permanent observatories hosting superconducting gravimeters and from repeated absolute gravity measurements in about 15 sites in France and worldwide. The SNO is coordinated by the Ecole et Observatoire des Sciences de la Terre (EOST) in Strasbourg and its other partners are the Observatoire Midi Pyrénées Toulouse (OMP), the Observatoire de Recherche Méditerranéen de l’Environnement (OREME) and the Observatoire de la Côte d’Azur (OCA).
LNE-SYRTE is responsible for the primary metrology missions of gravimetry in France. The gravimetry laboratory is located 30 km west of Paris in the French National Metrology Institute LNE-Trappes. It was designed to accommodate other gravimeters for metrological comparison tests and calibrations and is located close to the LNE kibble balance for which an absolute value of g is required. An absolute quantum gravimeter has been developed for this purpose. To evaluate its long-term sensitivity, ensure redundancy and guarantee the continuity of the gravitational signal in case of displacement of the reference gravimeter, a superconducting gravimeter, iGrav#005, was installed in the gravimetry laboratory in early 2013. Together with the quantum gravimeter, it allows the determination of the Planck constant and now the implementation of the new definition of the kilogram.
The International Geodynamics and Earth Tide Service (IGETS) was established in 2015 by the International Association of Geodesy. IGETS continues the activities of the Global Geodynamics Project (GGP) between 1997 and 2015 to support geodetic and geophysical research activities using data from superconducting gravimeters data within the context of an international network. In the framework of this network, the Trappes station (code TR) was created in 2013 by LNE-SYRTE (DOI tr005: http://doi.org/10.5880/igets.tr.l1.001).
Gravimetric data from LNE-SYRTE are accessible on the national SNO database (http://igets.u-strasbg.fr/SG_france.php) and the international IGETS database (http://isdc.gfz-potsdam.de/igets-data-base/) hosted by the ISDC (Information System and Data Centre) at the GFZ in Germany.
In addition, the laboratory is also equipped with a permanent LNE1 GNSS (Global Navigation Satellite Systems) antenna belonging to the RENAG network (RESIF-RENAG French National Geodetic Network, RESIF - Réseau Sismologique et Géodésique Français, https://doi.org/10.15778/resif.rg, 2017) which is the French contribution to EPOS for the Seismology and Geodesy components.
Contact : Sébastien Merlet