Network RTK can be used by RTK enabled VBOX 3i, VBOX 3iS, VBOX Touch and VBOX Sigma units as an alternative to a Static Base Station to receive RTK correction messages. It is particularly useful in situations where setting up a base station is not possible, for example if the roving vehicle must travel tens of kilometres away from the base station.
The most common method of Network RTK involves a two-way communication link which allows the roving vehicle to send its position to a service provider that is monitoring satellite observations from several reference stations around a country. The service provider will then calculate the appropriate corrections for the rovers location based on the data from nearby reference stations. This correction information is then returned to the rover in the same RTCM format as is used for a single fixed base station.
Most network RTK systems are internet based and utilise a protocol called NTRIP (Networked Transport of RTCM via Internet Protocol), this requires that the user maintains a constant internet connection in order to receive corrections, normally this is done via a cellular modem or smart phone.
The current VBOX firmware does not support NTRIP directly, however cellular modems with built in support are available, as are smartphone and desktop applications.
There are several Network RTK providers around the world, popular companies in the UK for example are Topnet Live and SmartNet. These providers can offer a subscription service to Racelogic VBOX RTK customers, who can then use these corrections directly into their units with the necessary intermediary hardware mentioned above.
Racelogic do provide an NTRIP Cellular Modem solution, more information on this is available here.
NTRIP Modem connected to VBOX Touch RTK