HOW GPS WORKS The GPS consists of three main segments: space, control, and user. Satellites, which are launched into specific orbits and monitored by ground station, transmit information in form of radio signals. Ground stations update the information from satellites and send update signals back to satellites. Users with GPS receivers can decode satellite signals to find helpful information such as a location in a desert. Space Segment The space segment includes 24 satellites that are …showed first 75 words of 807 total…

…showed last 75 words of 807 total…calculate the position. In addition, other factors need to be considered in getting a precise position. For example, the atmosphere can cause a change in the speed of light and creates an error. Another inaccuracy source is Selective Availability (SA), which is an intentional error caused by the U.S. Department of Defense. The purpose of SA is to prevent hostile forces or terrorist groups from taking advantage of GPS for producing precise lethal weapons.