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.
A GPS system will work efficiently in any place where you have access to the open sky. By pointing the GPS receiver towards the sky, you have a better chance of picking up numerous satellite signals. This does not mean that a GPS receiver will not work inside homes, in the forests, or where there are no open skies. It is just that in such locations, it may be difficult to pick up satellite signals, thus making it impossible to pinpoint your location.
Although the GPS system was initially created for use by the defense forces, it is now available to anyone. However, civilians can only make use of the Course Acquisition Signal, and not the Precision Signal that is restricted to military use. Both the signals will help to determine your location, but a Precision Signal is far more superior and accurate.
A GPS system is an alternative for those hard to understand maps and area guides. It can be used while traveling so that you need not refer to those navigation maps, can keep you from getting lost while trekking and hunting, and can also be used by anglers to mark a hot fishing spot!