WAAS (Wide Area Augmentation System) is an integrated system of ground based
reference stations and two geo stationary satellites broadcasting precision
differential GPS corrections to specialized GPS receivers. WAAS provides
enhanced accuracy via augmented GPS satellite signals, the next generation of
GPS accuracy. The WAAS augmented GPS signal corrects GPS signal errors caused by
ionosphere disturbances, timing and satellite orbit errors. In near continuous
broadcast since December of 1999, the WAAS system was developed for the FAA for
commercial aircraft precision approach landings. The WAAS signal is now
available for civilian use, offering extended coverage both inland and offshore
in comparison to land based DGPS systems.
