U.S. and Canada: The augmentation to global positioning system (GPS) to meet en route and terminal navigation, non-precision approach and precision approach CAT I accuracy, integrity, continuity and availability requirements. The ground system comprises a sparse network of ground reference stations and a master station linked by terrestrial communications. In the space system, an uplink from the master station provides information to geostationary satellites that transmit an integrity message, corrections and a GPS ranging signal to user avionics. abbreviation: WAAS see also: local area augmentation system (LAAS) Fr: système de renforcement à couverture étendue
A system of satellites and ground stations that provide GPS signal corrections for better position accuracy. A WAAS-capable receiver can give you a position accuracy of better than three meters, 95 percent of the time. (At this time, the system is still in the development stage and is not fully operational.) WAAS consists of approximately 25 ground reference stations positioned across the United States that monitor GPS satellite data. Two master stations, located on either coast, collect data from the reference stations and create a GPS correction message. For more information, see What is WAAS?, or visit the FAA's website.
A system of satellites and ground stations that provide GPS signal corrections for better position accuracy. A WAAS-capable receiver can give you a position accuracy of better than three meters, 95 percent of the time. WAAS consists of approximately 25 ground reference stations positioned across the United States that monitor GPS satellite data. Two master stations, located on either coast, collect data from the reference stations and create a GPS correction message. This correction accounts for GPS satellite orbit and clock drift plus signal delays caused by the atmosphere and ionosphere. The corrected differential message is then broadcast through one of two geostationary satellites, or satellites with a fixed position over the equator. The information is compatible with the basic GPS signal structure, which means any WAAS-enabled GPS receiver can read the signal.
A U.S. Federal Aviation Authority (FAA) system of equipment and software that supplements GPS accuracy, availability and integrity. The WAAS provides a satellite signal for WAAS users to support enroute and precision approach aircraft navigation.
The Wide Area Augmentation System (WAAS) is an extremely accurate 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.Federal Aviation Administration (FAA), http://gps.faa.gov/FAQ/faq-waas.htm FAQ for WAAS 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.