The use of real-time differential correction is the most convenient and productive method for operating GPS\GNSS surveys, as it allows the accuracy of measurements to be quickly and directly improved in the field.
The real-time positioning service provided by the FVG network distributes differential corrections both of code for navigation with a precision of metres (DGPS) and of phase for positioning with a precision of a few centimetres (RTK). The differential corrections are available both from the network and referred to the single master station.

The network solutions are built with the following systems:

- VRS (Virtual Reference Station): the user sends the control centre their approximate location. Based on the data of the surrounding permanent stations, the network generates a virtual station next to the rover and sends them a personalised correction.

- MAC (Master Auxiliary Concept): the network processing consists of estimating the differences between the data of one station (Master) and those of the others (Auxiliary), reducing all the observations to the same level of overall ambiguity. The information is packaged compactly and sent to the receiver rover without performing any spatial modelling. The user can choose the most appropriate manner to process the data received. The MAC mode requires the use of RTCM format in version 3.0 and later.

- I-MAC (Individualised MAC): is a method similar to VRS, but the corrections are referred to a real, non-virtual station.

- Nearest: the user is sent the correction coming from the nearest permanent station to the rover.

The characteristics of the differential corrections of the distributed network are summarised in the following table:

 
Mountpoint Tipo di Soluzione Formato
SingleBase_RTCM23 Nearest – RTK RTCM 2.3
SingleBase_RTCM31 Nearest  – RTK RTCM 3.0
VRS_RTCM23 VRS – RTK RTCM 2.3
VRS_RTCM31 VRS – RTK RTCM 3.1
VRS_CMR VRS – RTK CMR
MAC_RTCM31 MAC – RTK RTCM 3.1
IMAC_RTCM3 IMAC – RTK RTCM 3.1
 

All the mountpoints listed above require the rover receiver to send an NMEA string (GGA position) to identify its position. The “SingleBase” mountpoints do not provide a network solution but are able, through the NMEA string provided by the rover, to pinpoint its position and transmit the differential correction referred to the nearest permanent station (Nearest) to the rover at that moment.
The mountpoints listed below refer to the single permanent stations, and provide solutions for both DGPS and RTK: :

 
Mountpoint Tipo di Soluzione Formato
Ampezzo_DGPS Singola Base – DGPS RTCM 2.1
Ampezzo_RTK Singola Base – RTK RTCM 2.3
Bevazzana_DGPS Singola Base – DGPS RTCM 2.1
Bevazzana _RTK Singola Base – RTK RTCM 2.3
Barcis_DGPS Singola Base – DGPS RTCM 2.1
Barcis _RTK Singola Base – RTK RTCM 2.3
Cervignano_DGPS Singola Base – DGPS RTCM 2.1
Cervignano_RTK Singola Base – RTK RTCM 2.3
Gorizia_DGPS Singola Base – DGPS RTCM 2.1
Gorizia _RTK Singola Base – RTK RTCM 2.3
Pordenone_DGPS Singola Base – DGPS RTCM 2.1
Pordenone _RTK Singola Base – RTK RTCM 2.3
MoggioUdinese_DGPS Singola Base – DGPS RTCM 2.1
MoggioUdinese_RTK Singola Base – RTK RTCM 2.3
Tarvisio_DGPS Singola Base – DGPS RTCM 2.1
Tarvisio_RTK Singola Base – RTK RTCM 2.3
Trieste_DGPS Singola Base – DGPS RTCM 2.1
Trieste_RTK Singola Base – RTK RTCM 2.3
Udine_DGPS Singola Base – DGPS RTCM 2.1
Udine_RTK Singola Base – RTK RTCM 2.3

 
Access to real-time positioning is realised via internet through an Ntrip caster (Networked Transport of RTCM via Internet Protocol) accessible at http://gnsscaster.regione.fvg.it:8080 or http://193.43.178.173:8080

Access to the real-time service is free, but is regulated through access credentials (username and password) that can be requested by emailing the duly completed application form, which can be downloaded from the Forms section of this site.

It is advisable to refer to the operation manual of your rover or to your dealer, for the correct configuration of your receiver for the utilisation of differential corrections in real time via Ntrip.
Ntrip account request form
The form should be sent to the following e-mail:
rete.gnss.marussi@regione.fvg.it

Access to the archive of the "historical data" network "A. Marussi" (when available) can be done by written and reasoned request by e-mail to rete.gnss.marussi@regione.fvg.it and depending on the load the work of the relevant departments.

It is hoped that there will be active collaboration with neighbouring operators of similar networks in the search for an ever better satisfaction of the expectations of respective users, for the harmonious and peaceful development of our communities.

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