About Gps; Introduction/Features - Bushnell Yardage Pro Yardage Pro Owner's Manual

About GPS

GPS stands for "Global Positioning System". launched by
the United States Department of Defense, GPS consists of
a constellation of 32 satellites orbiting the earth at nearly
11,000 miles. These satellites are traveling at a speed
that allows them to circle the earth twice each day while
emitting a very low power signal. The signals are timed by
clocks that are highly accurate and are received by one of
5 ground stations. These ground stations use the precisely
timed signal to determine each satellite's exact position in
orbit. your GPS receiver can "hear" the signal sent by the
satellite. By calculating the position and distance of at least
4 satellites, accurate latitude, longitude and altitude location
information can be determined. wAAS adds to your GPS's
accuracy. wAAS stands for wide Area Augmentation System.
wAAS was designed by the United States federal Aviation
Administration, primarily to add in the accuracy of GPS for
planes. wAAS consists of the group of additional ground
stations placed at known and precisely located spots. These
ground stations then work with a master station to correct
the satellite signals improving accuracy to within nearly 3
meters.
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