| GPS stands for Global Positioning System and was | | | | received by a receiver, the farther away the |
| initially designed to be used by the U.S. military and | | | | satellite is. If a GPS is receiving signals from three |
| is operated by the U.S. Defense Department. This | | | | satellites it can calculate latitude and longitude. |
| system consists of 24 satellites, these satellites | | | | Altitude can be determined if the GPS is receiving |
| are 12,000 miles above us, are constantly moving | | | | signals from four satellites. |
| in a precise orbit, have an atomic clock, and are | | | | GPS can be used for navigating your car through |
| solar powered. They do have a battery backup | | | | traffic day-to-day or tracking a fleet of vehicles. |
| so they will continue to run in the event of a solar | | | | Not only can a driver use a GPS for directions the |
| eclipse, and each satellites has a small rocket | | | | main office knows where that vehicle is and the |
| booster to maintain their orbit. The first satellite | | | | speed of the vehicle. GPS can be used while on |
| was launched in 1978 and it wasn't until 1994 | | | | vacation for activities such as hiking, camping, or |
| when there were a total of 24 satellites. Each | | | | hunting. Is your passion fishing but get frustrated |
| satellite has a life expectancy of about 10 years, | | | | trying to find the fish? With a fish finder which |
| so new satellites are constantly being built and | | | | uses both GPS technology and sonar you'll know |
| launched. Each satellite weighs about 2,000 pounds | | | | exactly where to go to find those fish. GPS |
| and is approximately 17 feet in width when the | | | | technology is also being used as a way to track |
| solar panels are extended. In the 1980s the GPS | | | | your pet if he wanders off or to safeguard a pet |
| became available to the public, and although it is | | | | from being stolen. |
| still maintain by the U.S. Defense Department | | | | Another use for GPS is as a child finder with a |
| there is no charge for its usage by the public. | | | | receiver in a child's cell phone or wristwatch to |
| These 24 satellites orbit the earth twice a day | | | | ensure a child's safety. It can be used in a |
| and continuously sends the location of the satellite. | | | | teenager's car in order to both know where they |
| A GPS system can tell how far a satellite is away | | | | and how fast they are driving. This could also be |
| by comparing the time difference between the | | | | used to keep track of someone who tends to |
| time a signal was transmitted and the time it was | | | | 'roam' but is not capable enough to find there |
| received, the longer it takes the signal to be | | | | way back; i.e. someone with Alzheimer's disease. |