How Does a Garmin GPS System Work?
Garmin Global Positioning System receivers work by using GPS satellites that orbit the Earth. These satellites circle the Earth twice each day and transmit signals back. There are 24 GPS satellites in orbit as of 2008. The orbits have been arranged so that there are at least four satellites visible to GPS receivers at any one time. The Garmin GPS receiver picks up the satellite signals and uses them to triangulate the user’s location through a process called trilateration. If you know you are 15 miles away from satellite A, you could be anywhere in a sphere with a 15-mile radius. But if you know that you are 10 miles from satellite B, you now have a second sphere that must converge with satellite A’s sphere. To further triangulate, you add a third sphere that says that you are 10 miles from satellite C. You now know that you are anywhere within that small area where those three spheres converge. When the Garmin GPS receives the information from the satellites, it compares both the time
