Austrian Positioning Service
The Austrian Positioning Service ( APOS ) is the GNSS satellite positioning service of the Federal Office for Metrology and Surveying (BEV) which uses GNSS signals, processes them centrally and uses parameters derived from them, e.g. B. in the form of the "Virtual Reference Station - VRS" to improve the accuracy of satellite-based measurements.
Suitability / use
- Basic, cadastral and scientific surveys
- Agriculture and Forestry
- Construction and engineering surveying
- Measurement recordings with aircraft
- geological and geophysical point surveys
- GIS surveys
- Staking out and routing
- Machine controls
Development and national / international cooperation
The decision to set up APOS was taken by the BEV in 2002. This was followed in 2003 by the signing of a cooperation agreement between the national surveying authorities of Bavaria , Baden-Württemberg , Switzerland and Austria for the cross-border networking of reference stations that exclusively use GPS signals. The establishment of the first GPS substation networks finally began in Vorarlberg and Upper Austria .
The APOS products became official BEV products in 2006 after a test phase of around one year.
The further consolidation of the APOS-GNSS reference station network in Austria, with additional use of the Russian GLONASS system , took place over the years through the integration of the reference stations of the Austrian Academy of Sciences / Institute for Space Research (ÖAW / IWF), the Carinthian Electricity Corporation KELAG and through the establishment of further reference stations distributed all over Austria by the BEV. The integration of the border GNSS reference stations of the national surveying administrations of the other neighboring countries by the BEV took place gradually on the basis of the conclusion of bilateral cooperation agreements.
Since May 28, 2019, the data from GALILEO satellites has also been integrated into the state positioning service APOS. This made APOS the first Austrian positioning service to also provide GALILEO correction data for satellite-based surveying and positioning for the whole of Germany. 37 GNSS reference stations are currently operated permanently by the BEV, one of them in cooperation with the Leopold-Franzens-University Innsbruck (LFUI) .
APOS reference stations represent the top level of the Austrian 3D reference frame and correspond to the Class A - EUREF specification (1 cm - repeatability).
Products and their accuracies
APOS Real Time
Within the Austrian national territory, a comprehensive provision of homogeneous 3D coordinates in the European Terrestrial Reference System ETRS89 with either dm or cm accuracy is guaranteed in real time . APOS Real Time enables real-time positioning either according to the concept of the “Virtual Reference Station - VRS” or the “Master Auxiliary Concept - MAC”. The distance-dependent influences are recorded and taken into account centrally, which ensures homogeneous accuracy across the board. The data is provided exclusively via mobile internet via packet-switched data transmission using the NTRIP protocol. In addition, there is the option of using a comprehensive 3D online transformation from ETRS89 to the MGI system of the Austrian land surveying system with dm accuracy based on grid technology with the help of the GIS grid of the BEV.
GIS-Grid: Online transformation from the ETRS89 system to the state MGI system
On the basis of a close-knit, interpolated grid (mesh size 30 ″ × 45 ″), which describes the deviations (inhomogeneities) between the European system ETRS89 and the Austrian system of national surveying MGI, APOS Real Time (RTK) can be used for a uniform online -Transformation from the ETRS89 system into the state system MGI can be carried out with dm accuracy in real time . This GIS grid was made up of approx. 28,000 identification points from the state control point field 1. – 5. Order derived.
APOS postprocessing
For post-processing applications via "BEV Store APOS" on the website of the BEV the observation data of all Austrian APOS be GNSS reference stations in format RINEX for evaluations with centimeter accuracy in the intervals 1, 5, 15 and 30 seconds available. The data are available up to 60 days from the date of recording, whereby the 30 second data is also archived for longer periods and is available on request.