Garmin GPS 90, Руководство пользователя и справочник

Страница: 10 / 92

2
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
gps 90 manual 8/6/98 9:57 AM Page 2