NTRIP

(Accessible text version)

Transmission of GNSS Real-Time Data via Mobile Internet

Task

The Bundesamt für Kartographie und Geodä sie (Federal Agency for Cartography and Geodesy, BKG) is responsible for the realization and provision of standard geodetic reference networks for the territory of the Federal Republic of Germany.

To provide real-time users access to a uniform three-dimensional reference system BKG performs the following tasks:

Operation of the Geodetic Reference Network GREF as a real-time data acquisition system
Further development of the Internet transport technique NTRIP for the transmission of GNSS real-time data to the respective users
Standardization of NTRIP within the frame of the Radio Technical Commission for Maritime Services (RTCM)
Participation in the development of internetbased real-time positioning services
Embedding of the activities into the context of a European and world-wide distribution of data of Global Navigation Satellite System (GNSS) via Internet (EUREF-IP and Real-time IGS)

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NTRIP Internet Broadcaster
Modified “Internet Radio” Technology under Linux operating system
Simultaneous distribution of many GNSS realtime data streams in support of simultaneously listening clients

Standard TCP/IP/HTTP protocol for data dissemination
Remote operation and maintenance via TELNET, FTP and HTTP
Modern client-server architecture with maximum operational reliability and security
Interruption-free configuration during the operation
Complex authentication, authorization and billing procedures

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NTRIP Real-Time Services
Positioning in real-time with meter accuracy up to centimetre accuracy
Correction data reception, e.g. by means of pocket PC and mobile telephone
GNSS correction data reception and user application on one device
Use of GPRS/UMTS mobile radio technology
Use of satellite clock corrections estimated from large-scale networks

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NTRIP Data Streams
Presently approximately 2000 real-time GNSS globally available data streams
Different data formats: RTCM, RTCA, raw data, et al.
Contributions from different networks: IGS, EUREF, GREF, SAPOS, ascos, et al.

Reception of the data by means of the program “GNSS Internet Radio” (Linux, Windows 2000/NT/XP, Windows CE)
Decoding, conversion and synchronization by means of the programs (Linux, Windows, Solaris, Mac)

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