Garmin GPS 90 - Manual (Page 10)

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What is GPS?
GPS (Global Positioning System) is a satellite-based navigation system developed
by the U. S. Department of Defense to provide a consistent, accurate method of
simplifying navigation. Originally designed for military applications, it also pro-
vides commercial and recreational users with 24-hour, worldwide navigation cover-
age with accuracy to 15 meters (49 feet).
How Does GPS Work?
GPS navigation uses satellite ranging to determine your position in relation to a
set of satellites orbiting the earth. The GPS constellation is made up of 24 satellites,
which continuously send radio signals containing precise position and time infor-
mation for each satellite back to earth.
By knowing the position of any 3 or 4 of these satellites and calculating various
time differences between the transmitted signals, your GPS receiver can determine
its present position anywhere on earth. And once you’re under way, your GPS con-
tinuously updates your position and provides speed and track information.
What are the Advantages of GPS Navigation?
The GPS system provides pilots with a highly efficient, reliable system for point-
to-point navigation without total reliance on traditional ground-based navigation
aids. GPS takes navigation to a higher level by providing accurate position and
course information, anywhere in the world, regardless of the weather or your prox-
imity to traditional navaids. The accuracy and coverage of GPS navigation can help
make your flying safer, smarter and more efficient wherever you may travel.
Introduction
GPS Overview
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