DGPS (Differential GPS)
General term for a GPS measurement procedures with less accuracy using simultaneously at least 2 GNSS receivers for post processing or Real Time applications.
Real Time Application
All satellite-based measurement methods that use mobile equipment for quick data transfer.
ETRS89 (European Terrestrial Reference System 1989)
European reference system that was defined by the European sub-commission of the IAG (EUREF) and that is explicitly acknowledged as the binding coordinate reference system in the INSPIRE Directive. In Austria ETRS89 is realized by ETRS89 / Austria 2002, the official Austrian datum based on a EUREF measurement campaign in Austria in 2002.
EUREF (European Reference Frame)
The IAG Reference Frame Sub-Commission for Europe which deals with the definition, realization and maintenance of the European Reference System in 3-D and 1-D.
The space-based satellite navigation system of the European Union.
The space-based satellite navigation systems of Russia and the USA.
GNSS (Global Navigation Satellite System)
General term for a space-based satellite navigation system (GPS, GLONASS, GALILEO, etc.) and its augmentation system (WAAS, EGNOS, etc.).
GNSS Reference Station
In case of APOS a station based on the criteria of EUREF (mm-accuracy, high stability, high data availability) with the infrastructure for the permanent data transfer (permanent station) to a computer centre.
Directive for the establishing of a geodata infrastructure for the European Community. In Austria it is implemented within the frame of the Geodateninfrastrukturgesetzes - GeoDIG.
Network messages based on the concept developed by LEICA Geosystems.
Describes the provision of an internet connection on mobile devices via different access technologies (as of 2G).
NMEA (National Marine Electronics Association)
NMEA 0813 is an international standard format derived from marine communication for the transmission of position data.
NTRIP (Networked Transport of RTCM via Internet Protocol)
A procedure developed by the German Federal Agency for Cartography and Geodesy (BKG) and the Dortmund University Department of Computer Science for streaming differential GPS (DGPS) data over the internet in accordance with specification published by RTCM.
Subsequent calculation of baselines with the help of recorded respectively converted raw data (e.g. in RINEX format).
RINEX (Receiver Independent Exchange Format)
Receiver-neutral, international and standardised data exchange format for GNSS measurement data.
RTCM – SC104
(Radio Technical Commission for Maritime Services - Special Committee Number 104)
Standard for the transmission of corrections and raw data.
RTK (Real Time Kinematik)
A DGPS measurement method of high accuracy (also "PDGPS - Precise DGPS") based on the data transfer (correction or raw data) from a reference station to a rover (user) in real time. The term is originally derived from the highly accurate positioning of objects in motion.
UTC (Universal Time Coordinated)
The primary time standard by which the world regulates clocks and time. For Austria: summer time minus 2 hours / winter time minus 1 hour.
VRS (Virtual Reference Station)
Synthetic (virtual) reference station that is generated by the central networking software exactly for the approximate position transmitted by the rover in NMEA format and that can be directly processed by the rover; the provision of virtuel GNSS measurement data and of distance-dependant model parameters for satellite orbits, troposphere and ionosphere in RTCM format make short measurement periods (short baselines) possible.