WAAS at 15.

The Wide Area Augmentation System (WAAS) achieved Initial Operating Capability (IOC) in July 2003. At IOC, WAAS had 25 reference stations in the Conterminous United States, Hawaii, Alaska, and San Juan, Puerto Rico, two master stations, and four uplink stations supporting two narrowband L1 only Geostationary Earth Orbit (GEO) satellites. Today, WAAS has 38 reference stations including four in Canada and five in Mexico, three master stations, and six uplink stations supporting three wide band L1/L5 GEO satellites. In addition to the architectural expansion, the Federal Aviation Administration (FAA) continued to evolve and maintain the algorithms, hardware, and software. With WAAS now turning 15 years of age, this paper takes stock of these modifications and details the improved service and integrity that has occurred since 2003. [ABSTRACT FROM AUTHOR]