A Global Positioning System or GPS is a technological innovation that uses a number of satellites in the earth’s orbit, to transmit signals back to earth enabling GPS receivers to calculate and identify the exact location, time information and speed to the user. The GPS receivers can be able to pinpoint the person’s location at anytime using signals from either three or more satellites. Originally, the GPS was created by the US Department of Defense to be used for military purposes. Though the system started being used in the 1980’s it became available to public use in the 1990’s. The main advantage of the GPS is that it can be able to function even in all weather condition any time, day or night.

GPS receivers operate using clocks that are less accurate while the satellites use accurate atomic clocks. Because of this, there is a timing error when the GPS receiver gets the satellite signals. Since the signals arriving to the receiver from the three satellites are measured simultaneously, the distance measurements are falsified by the receiver’s clock error. Therefore, to accurately measure the position of the receiver, four unknowns are required namely; the three satellite coordinates and the receivers clock error. To solve the four unknowns at least four satellites are required. The use of four satellites allows the GPS to determine the location with a pinpoint accuracy. With the four satellites, the receiver can now be able to calculate accurate estimates of the receiver’s clock and its location. The functioning of the Global Positioning System may sound quite complicated but it is simple if followed keenly.