GPS Satellites ExplainedLocation, Speed, Direction, Altitude
What is GPS?
The Global Positioning System (GPS) is currently the only fully functional Global Navigation Satellite System (GNSS). More than two dozen GPS satellites are in medium Earth orbit, transmitting signals allowing GPS receivers to determine the receiver’s location, speed and direction.
The Global Positioning System (GPS) is a U.S.-owned utility that provides users with positioning, navigation, and timing (PNT) services. This system consists of three segments: the space segment, the control segment, and the user segment. The U.S. Air Force develops, maintains, and operates the space and control segments. View GPS.gov
Developed by the United States Department of Defense, it was officially named NAVSTAR GPS (NAVigation Satellite Timing and Ranging Global Positioning System). The United States Air Force 50th Space Wing manages the satellite constellation. The cost of maintaining the system is approximately US$750 million per year, which includes the replacement of aging satellites and research and development. Despite this fact, GPS is free for civilian use as a public good.
How GPS Works
A GPS receiver calculates its position by measuring the distance between itself and three or more GPS satellites. Since the signal travels at a known speed, measuring the time delay between transmission and reception of each GPS radio signal gives the distance to each satellite.
Read more info at GPS.gov.