Navigational Devices

What is GPS?

The Global Positioning System (GPS) is a satellite-based navigation system made up of at least 24 satellites. GPS works in any weather conditions, anywhere in the world, 24 hours a day, with no subscription fees or setup charges. The U.S. Department of Defense originally put the satellites into orbit for military use, but they were made available for civilian use in the 1980s.

How GPS works

GPS satellites circle the Earth twice a day in a precise orbit. Each satellite transmits a unique signal and orbital parameters that allow GPS devices to decode and compute the precise location of the satellite. GPS receivers use this information and trilateration to calculate a user's exact location. Essentially, the GPS receiver measures the distance to each satellite by the amount of time it takes to receive a transmitted signal. With distance measurements from a few more satellites, the receiver can determine a user's position and display it electronically to measure your running route with a GPS Watch, find a way home with a Car GPS or adventure anywhere with a Handheld GPS.

Once your position has been determined, the GPS unit can calculate other information, such as:

• Speed
• Bearing
• Track
• Trip distance
• Distance to destination
• Sunrise and sunset time
• And more