Where Are We?: A Look at Global Positioning Systems on the
Market Today The global positioning system (GPS) was developed
by the U.S. Department of Defense to provide information about
location, such as the coordinates of a military target. It is
now available for public use and has been incorporated into many
products, including boats, cars, planes, laptop computers, and
even telephones. GPS technology is especially useful for anyone
who travels a lot and knows the feeling of getting lost. How
Does It Work? The Department of Defense launched 24 satellites
into orbit, and using signals from these satellites, a GPS
receiver can calculate such information as altitude, longitude,
and latitude. A GPS receiver needs to be in the view of at least
three of these satellites to provide accurate data. Depending on
the location of the GPS receiver, precision can be down to a few
feet. The ideal conditions for GPS are a large open space with a
direct view of the sky. Unfortunately, the signal is less than
optimal in a ci