Satellite Navigation Augmentation Systems

Satellite-Based Augmentation Systems (SBAS) are networks of ground relay stations and geostatic satellites designed to receive satellite navigation signals and transmit corrected time and distance measurements that greatly improve accuracy. Observation and relay stations have been set at known positions all over the world, while their geostatic satellites continuously maintain a fixed position above the Earth. Using these known values for distance, SBAS corrects satellite navigation signals for atmospheric delays, incorrect satellite positioning and poor geometry, sometimes caused by inline or close alignment of satellites, increasing accuracy in specific regions. SBAS is vital to providing the reliability and precision required by aviation and other precision-critical applications. Using the same signal frequencies as satellite navigation, SBAS-enabled receivers are inter-compatible. Three augmentation systems are currently in varying stages of operation and development covering North America, Europe and Asia. Already the incredibly accurate positioning capabilities of SBAS are being used in agriculture, development, mining and many other industries as well as hiking, boating, hunting, travel and an expanse of other leisure and business activities.

WAAS (Wide Area Augmentation System)
In North America, WAAS provides satellite navigation correction and validation, making WAAS-enabled receivers at least five times more accurate than standard devices. WAAS relay stations have been set at known positions throughout North America.

SBAS-enabled receivers do not require any additional equipment to use WAAS correction signals and, as with satellite navigation signals, there are no setup or subscription fees. WAAS is accurate to within three meters or less. System upgrades are being developed which will soon provide accuracy to well within one meter.

In 2003, the FAA (Federal Aviation Administration) plans to certify WAAS for use in low-altitude maneuvering, instrument approach and other sensitive aviation applications.

EGNOS (European Geostationary Navigation Overlay System)
EGNOS provides satellite navigation correction and validation throughout Europe, making EGNOS-enabled receivers at least three times more accurate than standard devices. EGNOS relay stations have been set at known positions throughout Europe.

SBAS-enabled receivers do not require any additional equipment to use EGNOS correction signals and, as with satellite navigation signals, there are no setup or subscription fees. Providing accuracy to within five meters or less, EGNOS is scheduled for full operation in 2004 and represents the first step toward Europe's GALILEO global satellite navigation system.

More about EGNOS.

MSAS (Multifunctional Transport Satellite-based Augmentation System)
Throughout Asia, MSAS provides satellite navigation correction and validation, making SBAS-enabled receivers at least three times more accurate than standard devices. MSAS relay stations have been set at known positions throughout Asia.

SBAS-enabled receivers do not require any additional equipment to use MSAS correction signals and, as with satellite navigation signals, there are no setup or subscription fees. Providing accuracy to within 5 meters or less, MSAS is scheduled for full operation in 2005 and will expand safety and air-traffic capacity in the Asia pacific regions.