GNCASTER

The NTRIP Protocol

NTRIP is the abbreviation for Network Transport of RTCM via Internet Protocol and has been developed by the German Bundesamt für Kartographie und Geodäsie (BKG) and the University of Dortmund/Germany for the real-time collection and exchange of GNSS data (see http://igs.ifag.de/pdf/NtripPaper.pdf).
NTRIP is a protocol similar to internet's http to transport RTCM or other GNSS data over internet. The NTRIP protocol specification (e.g. http://igs.ifag.de/pdf/NtripDocumentation.pdf) provides a complete description of NTRIP.

Since September 2004, NRIP 1.0 is part of the official RTCM standard.

NTRIP Concepts and Definitions

The Caster reads data streams from an arbitrary number of data Sources and provides the data streams to an arbitrary number of Users. See the following chart.

NTRIP Concept

The data stream may contain any type of streamable GPS data, but typically consists of periodic RTCM corrections for code and/or carrier phases. All communication is done through internet protocol (IP). The Caster makes copies of tha data as appropriate, in order to reduce the bandwidth between Source and Caster. A data stream can be identified by its so called mount point, which typically represents a reference station and/or service name.

The Caster can check the authentication of Sourcesand Users to allow only authorized connections. This allows in particular to control the access to the services provided by the caster, and to log the consumed resources for each user.