Global Navigation Satellite Systems (GNSS) permit the worldwide positioning with appropriate receiving systems, which process the microwave signals of the navigation satellites. Currently operating systems are the US Global Positioning System (GPS) and the Russian Glonass system. The European Galileo system will be operated in the near future.
In geodesy special satellite receiver are used, which observe at least on two different satellite frequencies. The delayed processing and the use of precise Earth orientation parameters from VLBI-observations and the use of improved orbit parameters leads to a precision of a few millimetre in point positioning. The flexible and the small dimensions of the receivers enable the easy setup of networks of permanent operating GNSS stations, which provide a frame of further densifications e.g. in the national land survey.
TIGO operates a hybrid GPS/Glonass Javad-receiver as a permanent station. The special constructed monument contains an inclinometer for the observation of its longterm stability. The monument allows also to perform the local tie measurements without removing the GPS/Glonass antenna.
The GPS/Glonass data are available through the International GPS Service (IGS) and serve primarily for the realization of the global terrestrial reference system.
TIGO owns four additional Ashtec Z12 receivers, which are used in a regional GPS-network in order to achieve knowledge about the regional stability of the TIGO-site.
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