Spectra Precision Survey Pro v4.6 Recon and Nomad User Manual - Manual (Page 236)

User’s Manual – GPS Mode
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these corrections, such as Trimble VRS. A detailed description of
these technologies is beyond the scope of this manual. Please see
the end of this manual for references to more information.
Network Transfer of RTCM via Internet Protocol
(NTRIP)
The Network Transfer of RTCM via Internet Protocol (NTRIP) is a
standard established by the Radio Technical Commission for
Maritime Services (RTCM). The NTRIP specification describes a
standard for transferring satellite observation data over the Internet
in different correction formats (RTCM, CMR…) The NTRIP
specification also describes a standardized way for logging on to a
server and selecting a specific service to use, plus establishing a
method to use passwords and user names to access the service.
In Survey Pro, the term NTRIP is used to refer only to the method of
logging onto a GPS server to select a service and possibly enter a user
name and password. It is important to note that not all network GPS
systems have an NTRIP log on procedure, even if they use NTRIP as
a means of sending data over the Internet.
Virtual Reference Station (VRS)
Virtual Reference Station (VRS) GPS is a type of Networked RTK
solution. In VRS GPS, the server software calculates corrections to
the GPS observations based on the data from multiple continuously
operating base stations in the network. Then, when the user connects
to the network, the server software calculates observations for a
single base point that is close to the rover’s location. Although this
virtual base point does not actually exist on the ground, it is still
considered close to the rover’s location, so the rover RTK engine will
calculate base lines with precisions similar to base lines to a physical
base that is located close to the rover. For more information on VRS
and other networked RTK technologies, please see the references
section.