Plain English Meaning

A helper system that makes GPS more accurate and trustworthy for flying. It watches the GPS satellites from the ground, figures out the small errors, and beams corrections back up to the aircraft through another satellite, so the pilot's GPS position is good enough to fly approaches with.

Full Definition

A system that improves the accuracy, integrity, and availability of GPS signals by using a network of ground reference stations to monitor satellite errors and broadcasting correction data through geostationary satellites to suitably equipped aircraft receivers. In the , the SBAS implementation is the ), which enables GPS to be used for such as .