EUREF and the EUREF Permanent Network closely work with several other organizations:
The International GNSS Service (IGS)
The EUREF Permanent GPS Network is the European densification of the Global
Network of the International GNSS Service (IGS).
In January 1996 the International GNSS Service distributed a "CALL FOR PARTICIPATION AS IGS REGIONAL NETWORK ASSOCIATE ANALYSIS CENTRES (RNAAC) FOR REGIONAL STATION POSITION ANALYSES" (IGS-Mail No 1178) with as principal goal the implementation of the regional densification of the IGS network.
The EUREF Subcommission has responded to this call for participation and has expressed its willingness to act as IGS Regional Associate Analysis Centre who delivers weekly free-network solutions for the European region to the IGS Global Network Associate Analysis Centres.
The free-network solutions delivered by EUREF to the IGS are obtained by combining the weekly solutions from the EUREF Local Analysis Centres. In this way the EUREF permanent network fulfills one of its principal goals, which is to be considered as a true densification of the IGS network.
In May 1996, the IGS has officially accepted the EUREF proposal.
In a spirit of cross-fertilization, EUREF members are participating to e.g. the IGS real-time and multi-GNSS activities, the IGS antenna Working Group and the IGS Infrastructure Committee. In addition, IGS standards are used for the routine EPN operations.
The Network of European Meteorological Services (EUMETNET)
Memorandum of Understanding between EUMETNET and EUREF (Aug. 2007).
During the EUREF Symposium 2007 in London a Memorandum of Understanding between EUREF and EUMETNET was signed to facilitate data exchange and to promote increased of cooperation between the geodetic and meteorological communities in Europe. The meteorological interest in GNSS measurements is due to their sensitivity to water vapour. Water vapour is a key element in the hydrological cycle, not only related to rain, but also as a main contributor of the energy that drives atmospheric dynamics. Further it is an important greenhouse gas. The very inhomogeneous and highly variable distribution of water vapour makes it difficult to observe; the relation to heavy rain and flooding makes it an important variable in weather forecasting. Humidity observations are under sampled by the current meteorological observing system, usage of ground based GNSS data is an elegant and efficient way to improve this. Ground-based GNSS provides continuous, high temporal resolution measurements of the Zenith Total Delay (ZTD), from which Integrated Water Vapour (IWV) can be derived. The vast majority of high quality permanent GNSS sites are installed for positioning purposes, by geodetic institutions and private companies. To them the atmospheric delay is a noise term. The meteorological observing networks and computer models contain useful information about these fields, superior to climatological data, which can help geodesists to determine positions faster and/or more precisely.
The work in European GNSS meteorology is organized in a EUMETNET program called E-GVAP (EUMETNET GPS Water Vapour Programme) whose main purpose is to provide quality checked, ground based GNSS ZTD and IWV in Near Real Time (NRT) for use in operational Numerical Weather Prediction (NWP) models and in now-casting to the participating EUMETNET members. The core of E-GVAP is a close collaboration between geodesy and meteorology. With the MoU signed in London, EUREF provides to E-GVAP/EUMETNET free access to GNSS RINEX data of the EPN sites (EUREF Permanent Network), primarily established to define, realize, maintain and provide access to the European Reference Frame, for the determination of ZTDand IWV for meteorological applications. On the other hand, EUMETNET provides to the EPN troposphere coordinator access to the radiosonde data from more than 100 stations which could be used for an inter-technique comparison with GNSS-derived ZTD at co-colated sites.
The EPN runs almost 250 GNSS stations in a well-organized environment. With its hourly network serves as the backbone for the E-GVAP Network, made up of more than 1800 sites in Europe, and foreseen to further increase in future.
The state-of-the-art in GNSS data processing for meteorology is based on hourly updated NRT ZTD parameters, currently estimated from GPS observations only, forwarded to a data server for distribution to meteorological institutes. The data processing is carried out by operational E-GVAP Analysis Centers (AC), plus additional centers being still in a test phase and one AC acting as a combination center. A subset of the operational E-GVAP ACs are EUREF LACs as well. Using the expertise developed in the EUREF framework, they set up a NRT processing for ZTD estimations which follows the meteorological requirements. On the other hand, with the increasing demand on accuracy of positioning and navigation and with the increasing quality and resolution of NWP models the use of meteorological data might become more beneficial in space geodetic techniques and the EUREF community can play a leading role in the exploitation of meteorological data in the GNSS processing.
In meteorology observing sites have unique names. It is therefore important that GNSS sites being included in the EUREF - EUMETNET data exchange adhere to the guidelines regarding 4 character naming and DOMES number reported in the "Procedure for Becoming an EPN Station" document.
The Central European GPS Geodynamic Reference Network Consortium (CEGRN)
Memorandum of Understanding between CEGRN and EUREF (May 2011).
CEGRN is a scientific Consortium of Research Institutions committed to a coordinated program of measurements, technical developments for long-term international access to monitoring geodetic and geodynamic processes in Central Europe. The objective of the CEGRN-EUREF MoU is, in general, to facilitate the data exchange and promote the increase in the co-operation between the two parties, and in particular, to facilitate the densification of the European GNSS network for reference frame definition and geokinematical applications, and to support the ECGN (European Combined Geodetic Network) project. It is expected that a closer co-operation between EUREF and CEGRN will increase the support to the IAG Working Group "Integration of Dense Velocity Fields in the ITRF", and the availability of a combined solution with respect to a denser network.
The European Position Determination System (EUPOS)
Memorandum of Understanding between EUPOS and EUREF (June 2014).
EUPOS is an organisation of the European national dense GNSS networks and services. The contributing national services - at the moment mostly covering Central and Eastern Europe - are providing correction data for real time positioning and navigation, and observation data for geodetic post-processing fulfilling all positioning requirements. EUPOS acts to homogenize the national positioning services providing unified, well determined, commonly agreed standards and also support countries, where such services are under preparation providing elaborated standards and expertise. EUPOS represents the GNSS service providers in international bodies like UN OOSA, and RTCM 104.
The MoU between EUPOS and EUREF aims at facilitating the multifunctional use of the data and results stemming from the dense GNSS networks.