Global Positioning System
The Global Positioning System (GPS) is a worldwide satellite-based navigation system formed from the constellation of 24 satellites placed into orbit by the U.S. Department of Defense. The system was initially designed for the operation of U.S. military, but in the 1980s, the government made the system available for civilian use. Today’s GPS System is composed of 31 satellites; these satellites are spaced in orbit so that at any time a minimum of six satellites will be in view to users anywhere in the world. There are no subscription fees, setup charges or restrictions to use GPS.
How it works
GPS satellites circle the earth twice a day in a very precise orbit and transmit signal information to earth. These satellites continuously broadcast position and time data to users throughout the world. Using a fixed or portable receiver unit that receives data from the closest satellites, the GPS unit triangulates the data to determine the unit’s exact location (typically in latitude and longitude), elevation, speed, and time. This information is available around-the-clock anywhere in the world and is not dependent on weather.