WAAS is a wide area augmentation system belonging to SBAS. The full name of WAAS is Wide Area Augmentation System, translated as Wide Area Augmentation System. It is a system jointly developed by the US Department of Transportation (DOT) and the Federal Aviation Administration (FAA). Its main application is In the aviation field, such as aircraft GPS navigation.
The emergence of WAAS is to solve the problem that GPS cannot provide aircraft with very accurate altitude information and heading guidance, the distance from the runway, and the elevation information of all points along the approach. Prior to this, the US air traffic control system mainly used ILS (Instrument Landing System) and MLS (Microwave Landing System). The former was difficult and troublesome to implement, and during the development of the latter, GPS receivers began to appear again.
WAAS consists of three main parts: the ground part, the space part and the user part. The ground part of the reference station receives and monitors the GPS signals, makes corrections, and then sends them to the satellites in the space segment for rebroadcasting to the user segment.
The emergence of WAAS has improved the positioning accuracy of aircraft navigation, while also reducing the cost of airport navigation facilities and the cost of a single receiver installed on the aircraft.