|What is GPS?|
The Global Positioning System (GPS) is a group of 27 Earth-orbiting satellites (24 in operation and three extras in case one fails). When people talk about a "GPS," they usually mean a GPS receiver. The U.S. military developed and implemented this satellite network as a military navigation system but now lets everyone use the signals. Contrary to some press reports they have no intention of stopping this service as they use it for device location and missile tracking.