DESC: The ultimate in GPS spy and surveillance equipment. This GPS vehicle tracking system allows you to monitor where a car or vehicle has been, the speed that it traveled, and start and stop times. All of this information is tracked right down to useable street level detail. These units are perfect for monitoring the activity of personal vehicles, company cars and fleet vehicles. The Global Positioning System (GPS) is a worldwide radio-navigation system formed of 24 orbiting satellites and their ground stations. Launched and maintained by the U.S. Department of Defense, these satellites send a stream of signals to the earth's surface enabling a GPS receiver to calculate accurate positions within about 10 feet or less.