The Global Positioning System (GPS) is a constellation of 27
Earth-orbiting satellites (24 in operation + 3 extras)
The US military developed it as a military navigation system,
later opened up for everybody
Each satellite circles the globe at about 19,300 km, making two
complete rotations everyday
The orbits: at any time, anywhere on Earth, there are at least
four satellites visible in the sky
GPS receivers locate at least four satellites, figure the distance
to each, and use this information to deduce its own location.
This operation is based on a simple math principle called
trilateration
The Global Positioning System (GPS) is a constellation of 27Earth-orbiting satellites (24 in operation + 3 extras)The US military developed it as a military navigation system,later opened up for everybodyEach satellite circles the globe at about 19,300 km, making twocomplete rotations everydayThe orbits: at any time, anywhere on Earth, there are at leastfour satellites visible in the skyGPS receivers locate at least four satellites, figure the distanceto each, and use this information to deduce its own location.This operation is based on a simple math principle calledtrilateration
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