WAAS

The Wide Area Augmentation System (WAAS) is an elevated-accuracy navigation system developed for civil aviation by the Federal Aviation Administration (FAA), a division of the United States Department of Transportation (DOT). The system augments the Global Positioning System (or GPS) to provide the additional accuracy, integrity, and availability necessary to enable users to rely on GPS for all phases of flight, from en route through GLS approach for all qualified airports within the WAAS coverage area. Before WAAS, the U.S. National Airspace System (NAS) did not have the ability to provide horizontal and vertical navigation for precision approaches for all locations, as ground-based systems are quite expensive.
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n. haze, mist, gauze, shroud, bloom, patina, film, fluff

Wide Area Augmentation System
  

(See WIDE-AREA AUGMENTATION SYSTEM.)

 

WIDE AREA AUGMENTATION SYSTEM. WAAS