GPS stands for Global Positioning System. Typically, we use it to mean both a GPS receivers- or small units that transmit directions, coordinates, and time- and the large network of satellites that orbit Earth and transmit signals to those receivers. The Global Positioning System was originally conceived and operated by the United States military. It used encrypted signals to broadcast location. It was employed extensively during the Persian Gulf War in 1991. Then in 1995, the U.S. government opened up the Global Positioning System for civilians’ use. This move allowed nonmilitary people to find directions and locations.
The United States government owns a constellation of 27 satellites that orbit Earth, making up the Global Positioning System. Of this number, 24 satellites are actually in use, while the rest are held back just in case the system fails.
These satellites weigh about 2,000 pounds each. They orbit Earth at a rate of 7,000 miles an hour, which allows each satellite to completely circle the Earth twice in a 24 hour period. Each of the 24 satellites move in a mixed orbit so that it keeps it from crashing into another satellite and allows its position to be known at all times.
What is a Trilateration?
The method of identification, known as trilateration, is very similar to the way that GPS maps locations- although the satellite system works much more quickly. The biggest difference between the map method and the way the GPS works is that the map method is 2 dimensional, trilateration. This means that you are working with flat surfaces rather than with solid and objects that have some solidness in its properties. GPS receivers use 3 dimensional trilateration to find people or objects.
3-D trilateration works very similarly to the 2-D trilateration. However, instead of just using circles, they use spheres, the 3-D way of circles with more texture. Just like how you determine the lateration of the map, you have to draw out circles or spheres and have to line up and to find the lateration, find where all the circles/spheres meet and that is where they determine the location of the place or the person
