Satellite-Based Augmentation System

The Global Navigation Satellite System (GNSS) is the foundation of modern aeronautical navigation and consists of core satellite networks, being the United States of America Global Position System (GPS), Russian Federation Global Navigation Satellite System (GLONASS), European Galileo and China’s BeiDou Navigation Satellite System (BDS). The core satellite constellations do not meet civil aviation performance objectives and require augmentation in the form of aircraft-based augmentation system (ABAS), ground-based augmentation system (GBAS) or satellite-based augmentation system (SBAS).

ABAS is contained within the aircraft and achieves integrity by comparison of multiple position solutions and is suitable for two-dimensional navigation such as enroute and non-precision approach.

GBAS is a local area solution, typically at an aerodrome which monitors core constellation satellites from a closely spaced network of receivers to provide integrity alerting and improved accuracy to support three-dimensional navigation comparable to instrument landing systems (ILS) for precision-approach operations to decision heights as low as 200ft. GBAS has a future capability to support precision approach and landing operations without decision height.

SBAS is a wide-area system consisting of a network of ground reference stations that observe the core constellation satellites. The observations from the reference stations are processed at a central facility to develop an integrity message and corrections for satellite clock, ephemerous and propagation path. Observation from multiple reference stations is required to formulate a correction grid so that a user can apply the correction applicable to their location with the service area. The integrity and correction grid information are transmitted to users via geostationary satellites.

The aircraft user with the appropriate avionic receiver will benefit from enhanced navigation capability enabling 3D approaches and greater availability. Operational benefits include safety improvements, regularity of service and reduced disruptions due weather-related diversions. As a wide-area system, these capabilities can be realised without the need for installation and maintenance of location dedicated radio navigation aids.


The Southern Positioning Augmentation Network (SouthPAN) is a joint initiative of the Australia and New Zealand Governments to provide satellite-based augmentation system (SBAS) services for Australia and New Zealand. Geoscience Australia is the Australian Government lead agency, working in collaboration with Toitū Te Whenua Land Information New Zealand, which is responsible for the development, deployment and operation of SouthPAN.

SouthPAN will be certified for aviation use against the International Civil Aviation Organisation standards for safety, integrity, continuity of service and availability. It will be interoperable with avionics used for the United States Wide Area Augmentation System (WAAS) and European EGNOS.

See Geoscience Australia Southern Positioning Augmentation Network (SouthPAN) portal for additional SouthPAN information.