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GPS-Reference Frame Land Surveyor Corporation

Caused by the growing practical usage of satellite-methods, the expectations put upon the geodetical network of fiducial points keep raising. The main subject is to adjust the existing networks of fiducial points to the modern demands on quality and quantity. The homogenization of the network of fiducial points location will give the user the ability to use new surveying methods like GPS economically and without the loss of precision. At the same time a reduction of density of the fiducial points may be accomplished. In cooperation of the Federal Office for Calibration and Measurement (BEV) and the GPS-Netz Ziviltechniker GmbH (GPS-Work Cooperation for Surveying), the existing GPS-Net AGREF (approximately 80 points) is expanded by another 250 points to an Austrian GPS-Geodetical Reference Frame AREF-1. Differentiated out of the AREF-1, the 3-dimensional coordinates of the international frame ITRF94 form the basis for a modern, user-orientated network of fiducial points.  


Ä The GPS-Reference Frame Land Surveyor Corporation was established through an initiative of the Federal Chamber of Architects and Consulting Engineers. For public offices (Federal Government, states, communities) as well as energy supply company’s, a corporation-like status about special contracts is provided.

Ä The main focus of the corporation is the creation of a "high precision GPS-Reference Frame for Austria" and the realization of such a frame with the main focus on "nation-wide DGPS - Reference Frames."

Ä The GPS-Reference Frame Land Surveyor Corporation is the biggest and most effective grouping with GPS/GLONASS Know-how in Austria. 112 consulting engineers for land surveying are associates. The corporation is able to involve the associates and therefore has a capacity of more than 1000 employees (including 200 academics) and 50 two-frequency-receivers. In Combination with the agreement with the Federal Office of Metrology and Surveying (BEV) and the Austrian Academy of the Sciences (ÖAW), consensus about the quality and the officiality  of the evaluations is given.

Ä AREF-1 :Das Konzept zur Schaffung diese Netzes ist in der Dichte und Genauigkeit bisher einzigartig. Es wurde in Abstimmung mit der Österreichischen Akademie der Wissenschaft (Subgruppe: Österreichische geodätische Kommission - GPS) sowie den Universitäten wissenschaftlich entwickelt und geprüft. Durch laufend Beratungen und Arbeitssitzungen mit dieser Kommission ist eine fundierte Begleitung des Projektes nach dem Stande der technischen Wissenschaften gesichert.

Ä AREF-1 is a GPS-Basic Reference Frame of highest precision. The average precision of the points in all of Austria in location is +/- 8 mm, in height +/- 13 mm. This frame is the requirement and basis for applications with high precision and reliability in surveying, GIS, navigation, and other DGPS-realtime-applications. 

Ä Especially the necessity for example to offer homogeneous data for GIS-projects Austria-wide, lead to the foundation of the corporation. From a geodetical point of view it is not justifiable, for GIS-projects or line surveyings, not to have a standardized and absolutly correct reference frame. With a long-term coordinated procedure, a homogeneous quality of data is reached and a data-chaos is avoided. Nationwide projects and positionized telematics applications also require a standardized Geo-referencing.

Ä The GPS-Corporation also has come to an agreement with Univ.-Prof. Dr. Sünkel which results in a new evaluation of Austria's Geoids using the additional executed precision levelling of the GPS-Reference Frame Land Surveyor Corporation. Initial estimates expect an accuracy of +/- 1 cm at a length of 15 km.

ÄTransformations between WGS84-coordinates and the used frame are part of the services of the GPS-corporation. With entering in the agreement, you get a corporation-like status and take part of the Know-How-Transfer within our corporation.

ÄAREF-1 will be densified with smaller projects AREF-2 to -n. That way, the homogenization process of the network of control stations will be pushed and at the same time an oversurveying and insurance of AREF-1 is reached.

Ä AREF-1 is the introduction and pre-requirement for professional appliance of DGPS-solutions in realtime. The GPS-corporation, as the organisation of the corporation of the group surveying - Federal Office of Metrology and Surveying, Austrian Academy of the Sciences - has come to a pre-agreement with ORF (Austria's main TV station) about the introduction of a DGPS-service for all accuracy areas.

ÄDARC distribution through Ö1: DARC (Data Radio Channel) is a sub-bearer-modulation on a sound-broadcasting-signal similar to the RDS-Technology. However with this, data rates from up to 10 kBaud can be realized. Therefore RTCM Reference data V2.1 (ff), including bearer phases, can be transfered. Within a six month testing period the functionality of this DGPS data transfer method with the Ö1- bearer was tested. The positive solutions of the test users, as well as the promising statements of an extensive market research promise an enormous market potential. Since Mai 15, 1998 the DARC - DGPS - Service is in operating mode.

Ä DGPS Service – DARC: The first expansion includes 7 GPS- and 1-2 GLONASS reference stations. All 18 main transmitters of the ORF-net are sending RTCM corrections. The Data is controlled and supervised by the state of the technology. There are three accuracy-classes available for the user:

  • Sub Ten-meter
  • Sub Meter
  • Sub Decimeter

The next expansion will include 15 reference stations.

Ä With AREF-1 and DARC, the geodetical requirements for technical unobjectionable and reliable applications of GPS was created.

AREF is the reference frame –
DARC the telematic implementation method