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Article: Local, global positioning: aircraft navigation.(Differential Global Positioning System)(Brief Article)
- Article from:
- The Economist (US)
- Article date:
- September 26, 1998
CopyrightCOPYRIGHT 1998 Economist Newspaper Ltd. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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WHEN American mail planes wanted to fly at night in the 1920s, they used to get farmers to light bonfires to help them find their way. In-flight navigation has moved on since then. With the aid of the Global Positioning System (GPS)-a network of 24 satellites maintained by America's defence department-modern aircraft know their location to within a few tens of metres. But even GPS is too inaccurate, and thus too risky, for use during take-off and landing-the critical minutes in which 50% of all aircraft accidents occur.
Until now. On September 21st, a Continental Airlines Boeing MD-80 flew from Washington, DC, to Newark, New Jersey, and then on to Minneapolis, ...