Simply put, GBAS provides a satellite-based GPS alternative to the Instrument Landing System (ILS). The U.S. version of GBAS was initially referred to as the Local Area Augmentation System (LAAS). For more details, visit the Navigation Program website that describes GBAS: How it works.
 

If your company is considering selling GBAS to airports in the national airspace system, contact the Non-Federal Program.

If your airport is considering buying a GBAS, contact the Non-Federal Program.

GBAS has many benefits. For example, a single GBAS can support multiple runway ends. To Illustrate: If an airport has six runway ends and each has its own ILS, a single GBAS can replace (or supplement) all six of those ILS. Further details are available at Satellite Navigation - GBAS - Benefits.

A GBAS ground facility typically has a small building to shelter its computer, four reference-receiver antennas, and a VHF Data Broadcast (VDB) transmitter.

The list is growing, and includes Newark Liberty International Airport (EWR), George Bush Intercontinental Airport (HOU), and San Francisco International Airport (SFO).