About Gps - Navibe Back Track User Manual

About GPS

GPS (Global Positioning System) is a satellite navigation system developed by the U.S. Department of
Defense. GPS consists of 32 satellites orbiting around 11,000 miles above the surface of the Earth.
These satellites travel at speeds that allow them to orbit the planet twice a day and emit a low-powered
radio signal. These signals are received and recorded using five ground stations with extremely accurate
clocks. By using these extremely accurate clocks, the ground stations can determine with great precision
the position of every satellite in their orbit. Your GPS receiver is capable of "reading" the signals
transmitted by these satellites. By knowing the position and distance of al least 4 satellites, it's possible to
accurately calculate the receiver's current latitude, longitude and elevation.
WAAS enhances the accuracy of your GPS. WAAS stands for Wide Area Augmentation System and was
developed by the Federal Aviation Administration to augment the accuracy of GPS for aviation use. It
consists of additional ground stations that are placed at specific locations where the exact coordinates
are known. When used with a master station, the accuracy of satellite positioning signals can be
improved to almost three meters.
The Back Track must scan and detect signals from at least 3 such satellites in order to calculate your
current location and movement. The Back Track is designed for recreational use only. Please do not use
this product for industrial or professional surveying.
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