augmentation system

augmentation system

[‚ȯg·mən′tā·shən ‚sis·təm]
(aerospace engineering)
An electronic servomechanism or feedback control system which provides improvements in aircraft performance or pilot handling characteristics over that of the basic unaugmented aircraft.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

GPS augmentation system

A system that improves the accuracy of the GPS satellite navigation system. A satellite's positioning accuracy is impeded by errors in its clock and signal delays caused by atmospheric conditions. Also called a "differential GPS" (DGPS), an augmentation system compensates for those discrepancies by transmitting corrections to the GPS receivers either via satellite or terrestrial radio. Instead of the normal GPS accuracy, which is approximately 15 to 70 feet, augmented systems pinpoint a location within a range of two to 10 feet, depending on the system, and as little as four inches in the case of commercial systems.

They Work Because of Known Locations
An augmentation system uses earth stations that have been very carefully surveyed, and their exact locations are known with great precision. As they receive signals from the GPS satellites, they are compared with the values they should be receiving, and the differences are used to calculate corrections. The corrections are transmitted either to the GPS receivers via geostationary satellites or terrestrial radio.

Space Based vs. Ground Based
A space-based augmentation system (SBAS), also called a "wide area augmentation system," transmits corrections to one or more geostationary satellites, which have a wide footprint on earth. The augmentation satellites rotate with the earth and are always in a fixed location above the earth, unlike the GPS satellites, which revolve around the earth. The predominant space-based systems are WAAS in the U.S., CDGPS in Canada, EGNOS in Europe and MSAS in Japan (see WAAS, CDGPS, EGNOS and MSAS).

There are also commercial space-based systems such as OmniSTAR (, Fugro ( and StarFire (, which can pinpoint a location with extreme accuracy. Used in the oil, gas, mining and construction industries as well as agriculture, such systems require specialized receivers, not the in-dash navigation systems found in automobiles.

A ground-based augmentation system (GBAS) uses radio towers to transmit corrections to the GPS receiver. There are hundreds of ground-based augmentation systems around the world transmitting in a wide variety of frequencies, from 162.5 kHz to 2.95 MHz. In the U.S., the Nationwide Differential GPS ( NDGPS) system is a major example. See GPS, LORAN, Galileo and Selective Availability.

GPS Augmentation
A GPS receiver can obtain corrections from space-based or ground-based augmentation systems. The receivers must be specialized for each type of correction service, and many earlier receivers used only the GPS signals. This illustration highlights only the receiver signal paths. Each system comprises numerous earth stations and terrestrial processing centers.
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References in periodicals archive ?
EGNOS is a satellite-based augmentation system that improves the precision of satellite navigation signals in Europe.
Trimble's Condor GPS module is capable of receiving Satellite Based Augmentation System (SBAS) corrections, including the US Wide Area Augmentation System (WAAS) and the European Geostationary Overlay Service (EGNOS).
A national team led by Lockheed Martin has been selected by the Federal Aviation Administration (FAA) to provide ground stations and broadcast services that will support satellite navigation signals for aviation use in the Wide Area Augmentation System (WAAS).
The receiver also has a variety of features that promote exceptional position accuracy, including a Wide Area Augmentation System (WAAS) and Coast Guard Beacon Support (DGPS).
The focus of the update is the Maneuvering Characteristics Augmentation System, which was chiefly designed to counter the MAX's tendency to pitch up at high angles of attack while being hand flown and push the nose over in the case of an impending stall.
CEO Dennis Muilenberg tweeted a video where he said the test flight was carried out on Tuesday, adding that test pilots have completed 120 flights totaling more than 203 hours of airtime with the software fix for the Maneuvering Characteristics Augmentation System (MCAS).
The aircraft manufacturer's CEO Dennis Muilenburg was on board Wednesday's 737 MAX 7 demo flight which was upgraded with the new Maneuvering Characteristics Augmentation System (MCAS) software update, according to Boeing.
From an investor perspective, the worst case would be that the Ethiopian crash was caused by a totally new flight control system problem unrelated to the Maneuvering Characteristics Augmentation System, the analyst adds.
"There are no details" about the Maneuvering Characteristics Augmentation System in Boeing's latest manual updates, said Zwingly Silalahi.
The Raytheon-developed system is a key element of the Federal Aviation Administration's wide area augmentation system (WAAS), which offers commercial airline and general aviation pilots more direct flight paths, greater runway capability, precision approaches to airports and remote landing sites without dependence on local ground-based landing systems.
This is a ground based augmentation system that allows aircraft to navigate via satellite technology marking a departure from the use of radio-based instruments for landing.

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