Satellite Based Augmentation System ( SBAS; German satellite-based augmentation systems ) are satellite navigation systems, the other existing satellite navigation systems, especially GPS or GNSS general support. SBAS provides additional information that is broadcast by geosynchronous (usually geostationary ) satellites and increase reliability, accuracy and availability of position determination.
The following SBAS systems exist or are under construction, which are primarily intended for application in the air navigation field, but are also widely used beyond:
These systems use the same data format and similar signals so that SBAS -enabled receivers are suitable for all these systems. The recipient will receive the following information:
- Plausibility of the GNSS signals,
- Corrections for GNSS satellite clocks and railways,
- Corrections for ionospheric propagation delays related based on a data grid.
Using this information, the receiver can improve on to its effective position accuracy significantly from about 10 meters one meter. In addition, the signals that use the GPS L1 frequency and have GPS-C/A-Code-ähnliche properties, are used for pseudorange measurements, ie directly improve the availability of GNSS by imitating an additional system satellites.
There are other, mainly commercial services that could be described in a broader sense than SBAS:
- Starfix the company Fugro,
- OmniSTAR the company Trimble,
- Starfire the company John Deere,
- Various services of the company Veripos.
These services use geostationary satellites to send out supplementary information. But use other signals and data formats so that these services are not accessible and also the additional pseudorange measurements can be performed. Therefore, the achievable accuracy of position determination are partly significantly higher ( decimeter range).