Never Get Lost Again

Global Positioning System (GPS) is a navigational aid originally developed for the military. The system simply receives signals. It is the applied technology that gives the GPS its versatility.

{mosgoogle}If you have ever used map and compass, you will understand a little about how the GPS works. In order to find your position on a map, you need to have three points of reference. The intersecting line from the reference points is where you are. Map and compass work uses triangulation (bearings), GPS uses trilateration (distances) to calculate location. Satellites orbiting the earth emit unique signals that can be received by a GPS. The GPS software interprets the signal, identifying the satellite that it came from, where it was located, and the time that it took for the signal to reach the system. Once the receiver has both time and distance it begins to determine position.

Three satellites provide the intersection point and the fourth is used to check that the positioning is accurate. Accuracy depends upon the synchronization of atomic clocks in the satellites with the clock in the GPS system. Although the clock in the GPS is not atomic, utilizing the fourth satellite gives it that functionality as the internal clock adjusts itself to correct any discrepancy discovered.

GPS has gone far beyond its initial military application. Drivers can find their way through city streets, long distance trekkers use the technology to cross unfamiliar terrain, mariners and pilots use GPS enhanced data to cross the seas and skies.