Plain English Meaning

A helper system that watches GPS for errors and sends out corrections through a satellite, so the GPS in your aircraft becomes accurate and trustworthy enough to fly approaches down to low minimums.

Full Definition

A system that improves the accuracy, integrity, and availability of basic GPS signals by using a network of ground reference stations to measure GPS errors, then broadcasting correction and integrity data to aircraft via geostationary satellites. In the United States, the SBAS implementation is the Wide Area Augmentation System (WAAS), which enables GPS to be used for precision-like with .