GPS stands for Global Positioning System and was initially designed to be used by the U.S. military and is operated by the U.S. Defense Department. This system consists of 24 satellites, these satellites are 12,000 miles above us, are constantly moving in a precise orbit, have an atomic clock, and are solar powered. They do have a battery backup so they will continue to run in the event of a solar eclipse, and each satellites has a small rocket booster to maintain their orbit. The first satellite was launched in 1978 and it wasn’t until 1994 when there were a total of 24 satellites. Each satellite has a life expectancy of about 10 years, so new satellites are constantly being built and launched. Each satellite weighs about 2,000 pounds and is approximately 17 feet in width when the solar panels are extended. In the 1980s the GPS became available to the public, and although it is still maintain by the U.S. Defense Department there is no charge for its usage by the public.


These 24 satellites orbit the earth twice a day and continuously sends the location of the satellite. A GPS system can tell how far a satellite is away by comparing the time difference between the time a signal was transmitted and the time it was received, the longer it takes the signal to be received by a receiver, the farther away the satellite is. If a GPS is receiving signals from three satellites it can calculate latitude and longitude. Altitude can …