History
Initially designed for U.S. military navigational purposes, the government made GPS available for civilian use in the 1980s.
How GPS Works
GPS receivers use signals from satellites and reference systems throughout the U.S. to triangulate the geographic position of the user.
Function
A hiker checks his location on a GPS unit.
According to REI, basic GPS units provide the following functions: give your location in latitude and longitude, allow for point-to-point navigation, assist with route navigation and keep track of your route taken.
Features
GPS units come in a variety of models, from hand-held devices to in-car units. GPS models differ on screen size, number of internal maps, illumination options, antenna configurations and add-ons such as additional altimeter functions.
Warning
A GPS should not be solely relied upon in the wilderness. A GPS is an electronic device and can malfunction or run out of battery power. Pack a map and compass and know how to use them.
