GPS System Basics

GPS is an acronym for the Global Positioning System. The GPS system constitutes a group of 27 satellites that orbit the Earth. Of these, 24 are active satellites, whereas the remaining 3 are back up satellites. The GPS system is the brain child of the U.S. Department of Defense and was first invented to assist the operations of the United States Air Force.

The principles of Triangulation are what the GPS system is based on. The 24 active satellites relay signals to the earth's surface, which are then triangulated by a device known as a GPS receiver. On the basis of these signals, a person can pinpoint their exact location on the Earth. To pinpoint your specific location, your GPS receiver should be able to pick up a minimum of 3 signals from 3 different satellites. These signals are used to calculate the distance of each satellite from the other, as well as the distance of each satellite from the GPS receiver (in other words, you). These distances are then extrapolated, and your exact location is determined.

Obviously, the more satellite signals that you can pick up with your GPS receiver, the more specific a location you can identify. It is not uncommon to be able to determine a location right down to a street number if your GPS receiver is picking up enough number of active satellite signals.