The subcommission of the International Association of Geodesy (IAG) for the European reference frame (EUREF), in accordance with the first resolution made in Florence in 1990, recommends that European countries adopt the ETRS89 (European Terrestrial Reference System 1989). The EU (European Union), EuroControl (European Organisation for the Safety of Air Navigation), and EuroGraphics (European Association for Computer Graphics), as well as other national and European entities, recommend the transition to this system. The ETRS89 is currently used as a base to develop cartographic work and for all kinds of Earth observation sciences.
ETRS89 is a three-dimensional geodetic reference system, used as standard for highly accurate GPS georeferencing in Europe. It coincides with the ITRS in the ITRF89 1989.0 frame, which is equivalent to the ETRF89 frame, from where the ETRS89 system gets its name, and is based on the GRS80 reference ellipsoid. It is slightly different from the ellipsoid that the WGS84 currently uses. It is a reference system connected to the stable part of the European plate and moves together with the Eurasian Plate.
Even though the ETRS89 European reference system moves constantly like the global ITRSs, the relationship between them is known, and therefore, the coordinates of any georeferenced element can be transferred to an ITRS without losing accuracy.
As an example of the benefited systems, we can mention the real-time positioning system, RTKAT, that the Institut Cartogrà fic i Geològic de Catalunya offers users as part of the Integrated Geodetic Positioning System of Catalonia (SPGIC). This system works as a method to increase accuracy of global positioning systems such as GPS, which allows positioning with an accuracy of a few centimetres, consistently with the ETRS89 reference system.