The realization and maintenance of a Galileo Terrestrial Reference Frame (GTRF) is one of the components contributing to the system performance of Europes Global Navigation Satellite System Galileo. The GTRF shall be compatible with the latest International Terrestrial Reference Frame (ITRF) within a precision level of 3 cm (2 sigma). To achieve this, a Galileo Geodetic Service Provider (GGSP) has been defined by the project already in the early stages of the programme.
A prototype system, funded within the sixth framework program of the European Union, has been established from 2005 to 2009 by a consortium of geodetic institutions:
- Helmholtz-Zentrum Potsdam, Deutsches GeoForschungsZentrum (GFZ), Potsdam, Germany (Coordinator)
- European Space Operations Centre (ESA/ESOC), Darmstadt, Germany
- Astronomisches Institut der Universität Bern (AIUB), Berne, Switzerland
- Bundesamt für Kartographie und Geodäsie (BKG), Frankfurt/Main, Germany
- Institut National de l'Information Géographique et Forestière (IGN), Paris, France
These facilities are processing data from the Galileo Experimental Sensor Stations (GESS) and stations of the International GNSS Service (IGS) to obtain precise coordinates. To get a full and unlimited access to the GTRF additional products are generated like high-precision orbit and clock solutions and other key products like Earth orientation parameters, ionospheric corrections and system biases.
Only with such a complete and consistent set of high precision products the GGSP can truly fulfil its prime task of providing a reference frame to the various user communities. In addition, these high precision products will be extremely valuable for the validation of the operational products generated by Galileo Ground Mission Segment (GMS).
The prototype system was later incorporated in the Galileo ‘Time and Geodetic Validation Facility (TGVF)’and renamed the ‘Orbit Validation Facility (OVF)’. It has routinely processed data from GPS, the two experimental Giove satellites and also the first Galileo IOV satellites since 2011 based on state of the art standards and conventions. Finally it has been demonstrated that the GTRF produced by the TGVF-OVF can be maintained once Galileo reaches its operational stage.
- Gendt, G.; Altamimi, Z.; Dach, R.; Söhne, W.; Springer, T. (2011): GGSP: Realisation and maintenance of the Galileo Terrestrial Reference Frame. Advances in Space Research, 47, 2, 174-185.