M3G: an expanding catalogue of permanently tracking GNSS stations in Europe

The Metadata Management and Distribution System for Multiple GNSS Networks (M³G, https://gnss-metadata.eu), hosted by the Royal Observatory of Belgium, is one of the services of the European Plate Observing System (EPOS, https://www.epos-eu.org) and EUREF (http://euref.eu).

M³G provides the scientific as well as the non-scientific community with a state-of-the-art archive of information on permanently tracking GNSS stations in Europe, including the station description, the GNSS networks the stations contribute to, whether station observation data are publicly available, and how to access them. 

Since its first public release (2018), M³G has been under continuous development, to respond to the evolving needs of the GNSS community, to progress towards FAIR data principles and comply with GDPR. 

M³G offers APIs and an interactive user interface where any GNSS station manager, after registration, can insert all information relative to its GNSS stations and make this information publicly available. Consequently, the commitment of station managers to insert GNSS station metadata in M³G and their willingness to keep the information up to date is crucial for the success of M³G.

At the moment, M³G is used by 127 GNSS agencies and includes data from more than 2500 GNSS stations all over Europe, and more still in the process of being collected.

We will illustrate the rationale underlying M³G, the data that it provides and how these data can be accessed.