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Article: It's GREAT to TRIANGULATE.(Brief Article)
- Article from:
- Science World
- Article date:
- March 26, 2001
CopyrightCOPYRIGHT 2001 Scholastic, Inc. 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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Three GPS satellites are used to pinpoint your exact location on Earth. The method is an easy mathematical principle called triangulation. It states that an unknown point can be located if you know how far that point is from three known points.
You're looking down on Earth from the viewpoint of three satellites, above. Each of the satellites sends out radio waves in all directions. Grab a compass to find the location of your mystery point on Earth's surface.
1. Your Earth-bound GPS receiver indicates that Satellite 1 is 18,000 km (11,185 mi) away from the mystery point. Let's call that 2.5 cm (1 in.) on the small map above. Set your compass with ...