The EPN (EUREF Permanent GNSS Network) is part of the IAG (International Association of Geodesy) defining the European reference framework. The basic task and goal of this organization is to define and maintain the ETRS89 reference system with its products, reference frameworks. EPN is the organization responsible for the implementation of the reference frameworks over the territory of Europe. The primary goal of many EPN activities is to ensure the homogeneity of coordinates throughout Europe. Under various projects of EuroGeographics and INSPIRE, the homogeneity of coordinates is a major issued due to the rapid increase in the amount of GIS data and the necessity of their interoperability and exchange between the European countries.
The European Permanent Network (EPN) is a reference scientific and research basis composed of 266 continuously operating GNSS monitoring stations, whose precise coordinates are calculated on a weekly basis, used by the EUREF subcommittee of the International Geodetic Association (IAG) for the purposes of the realization and maintenance of the European terrestrial reference system, ETRS89. Institutionally supported by EuroGeographics and approved by the European Union as an integral part of the INSPIRE Directive, this reference system represents the backbone for all geographic, geodetic and geodynamic projects carried out over the territory of Europe, both nationally and internationally. All contributions to the EPN network are voluntary, with more than 100 European agencies, institutes and universities involved in the GNSS globalization project itself, and the high reliability of such a network is based on redundancy and uniform rules that guarantee the quality of raw GPS data and the resulting positions of base station. In addition to its key role in defining the ETRS89 geodetic datum, data from the EPN network are also used for a wide range of scientific applications such as monitoring deformation of Earth's crust surface layers, monitoring and modeling of the world sea and ocean levels, prediction.