The Region of Friuli Venezia Giulia and the Centre for Seismological Research (CRS) of the National Institute of Oceanography and Experimental Geophysics (OGS), are present in the territory of Friuli Venezia Giulia with two networks of permanent GNSS stations: the “A. Marussi” network and the FReDNet network (Friuli Regional Deformation Network). These entities, thanks to the abovementioned infrastructure, provide two services of differential correction for real-time precise positioning in the territory of the region.
The Region FVG initiated the “A. Marussi” GPS Network in 1997 in order to realise a geodetic infrastructure able to provide technological support to topographic and cadastral survey operations and for the use of advanced systems in the determination of geographical elements for automatic placement on regional cartography. The GPS network has represented from the outset, an essential instrument for all regional and private technicians whose responsibility is to carry out urgent and expeditious topographic measurements or, more simply, to localise relevant elements for the management and planning of the territory. It is also found and still is fundamental in the creation and continuous updating of the Regional Technical Map (CTRN).
The OGS, thanks to the data provided by the FReDNet network, proposes to develop scientific research aimed at improving the geodynamic model of the regional area for the characterisation of the tectonic processes of the region and of certain areas that are more critical from the seismic point of view. One of the objectives of FReDNet is that of supplying soil deformation data of a high quality and, for this reason, the permanent sites of this network satisfy specific requirements relating to visibility of the satellite constellation, installation of the GPS antenna (generally on rock outcrops), and geology. In the field of applied research, FReDNet has as its objective the experimentation, development, and distribution, on the regional territory, of real-time positioning services based on GNSS satellite technology (GPS and GLONASS) according to the most widely used modes of differential correction.

The Region of Friuli Venezia Giulia and the OGS have, pursuant to Regional Law no. 63 of 27th December 1991, signed a convention for the free exchange of cartographic and territorial data, not for profit and for the purpose of public interest.
That Convention was integrated with an Addendum in which the entities commit to:

- collaborate in the field of the exchange of GPS/GNSS data registered by the respective GPS/GNSS permanent networks, in the maintenance of the functionality of the networks and their respective services, and in the improvement of the GPS/GNSS monitoring infrastructure managed by them;
- define and implement a protocol of exchange for GPS/GNSS data distribution in real-time (differential corrections) for the provision of real-time precise positioning services, following the modality of GPS RTK and VRS, or equivalent, in the territory of the Friuli Venezia Giulia region;
- collaborate for maintaining or improving the positioning services already realised within the territory of the Friuli Venezia Giulia region, following the modality of GPS-RTK and VRS, or equivalent.

In order to achieve an integrated GNSS positioning service in the region, currently the calculation centres of the Region FVG and OGS acquire and distribute, via the internet using the Ntrip protocol, all the differential corrections in RTK single base mode, for both networks (“A. Marussi” and FReDNet).

The network solutions, such as VRS and FKP, are instead generated and distributed separately from any calculation centre on the basis of data from the user’s network. In this way, the network user is guaranteed a support that is reliable (redundancy of services and servers of calculation and distribution) and efficient (extensive coverage of the territory even with the service of single stations).
The real-time services provided by the FReDNet network are distributed following the new reference system ETRF2000 (2008.0) adopted by the Military Geographic Institute (IGM) for the framing of the Italian National Dynamic Network (RDN). This system will soon also be adopted in the real-time services distributed by the “A. Marussi” network although, currently, the system in use is ETRF89 of which the IGM95 network is a densification.

The real-time services provided by the two networks ( "A. Marussi" and "FReDNet") are distributed with respect to the reference system adopted the Military Geographic Institute (IGM) for the framing of the National Network Dynamics (RDN). The GNSS Network of the Autonomous Region Friuli Venezia Giulia "A. Marussi "is framed in the national geodetic system called RDN ETRS89-ETRF2000 the day February 24, 2017.

The Ntrip caster App for accessing the real-time positioning services of the “A. Marussi” network can be found at http://gnsscaster.regione.fvg.it:8080 or http://193.43.178.173:8080.
In addition to the mountpoints that refer to GNSS stations owned by the Region, which are summarised on the differential corrections in real-time page, there are also the mountpoints listed below that are linked to the stations of the FReDNet network:
 

Mountpoint Tipo di soluzione Formato
OGS_ACOM Singola Base - RTK RTCM 2.3
OGS_AFAL Singola Base - RTK  RTCM 2.3
OGS_CODR Singola Base - RTK  RTCM 2.3
OGS_FUSE Singola Base - RTK  RTCM 2.3
OGS_JOAN Singola Base - RTK  RTCM 2.3
OGS_MDEA Singola Base - RTK  RTCM 2.3
OGS_MPRA Singola Base - RTK  RTCM 2.3
OGS_NOVE Singola Base - RTK  RTCM 2.3
OGS_PAZO Singola Base - RTK  RTCM 2.3
OGS_TRIE Singola Base - RTK  RTCM 2.3
OGS_UDI1 Singola Base - RTK  RTCM 2.3
OGS_ZOUF Singola Base - RTK  RTCM 2.3
 

For free access to the service in real-time it is necessary to request access credentials (username and password) by emailing the application form, duly completed, which can be downloaded from the Forms section of the Differential Corrections in real-time page.

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