How does a global positioning system (GPS) WORK?
The basic principle of operation of GPS is that any point on Earth can be found if it is controlled from four different places. For that reason, the GPS uses 24 satellites in six different orbits at an altitude of 18,000 kms. So, at any time any place is guarded by four different satellites. The GPS device sends a signal to the four satellites. These satellites have a database that contains information of all places on earth. These four satellites, in turn, return the latitude, longitude and altitude of that particular location by referring to its database. • WHAT IS FM? FM is frequency modulation. Attach to a carrier wave in the transmitted radio frequency sound signal. The frequency of the radio wave is varied or adjusted properly. When the modulated wave is received by a radio, radio waves are filtered to reproduce audio signal. FM is less susceptible to noise compared with AM or amplitude modulation where the mixing is carried out by varying the amplitude. At the traffic signals TV
