  GPS satellite and earth images courtesy of NASA |
How does GPS work?
Vehicle tracking systems supplied by Pathfinder Vehicle Systems provides customers with a vehicle location accuracy down to between 3 and 5 metres!
The first experimental Global Positioning System satellite was launched in 1978 and GPS has now become indispensable for navigation around the world.
With atomic clocks on board the satellites accurate to within one microsecond, they also provide a precise time reference used in many applications including scientific study of earthquakes and synchronization of telecommunications networks.
The satellites also carry detectors as part of the United States Nuclear Detonation Detection System.
The system is named NAVSTAR GPS (Navigation Signal Timing and Ranging Global Positioning System). The satellite system is managed by the United States Air Force 50th Space Wing based at Schriever Air Force Base in California. Although the system is maintained by the USAF, it is free for public use.
At an altitude of 12,600 statute miles, each satellite passes over the same location on Earth twice a day. With 30 actively broadcasting satellites, orbits are arranged so that up to 10 satellites are within line of sight from almost anywhere on Earth.
The GPS receiver calculates its position by measuring the distance between itself and three or more GPS satellites. Measuring the time delay between transmission and reception of each GPS radio signal gives the distance to each satellite. The signals also carry information about the satellites' location. By determining the position of and distance to at least three satellites, the receiver can calculate its location.
The first experimental Global Positioning System satellite was launched in 1978 and GPS has now become indispensable for navigation around the world.
With atomic clocks on board the satellites accurate to within one microsecond, they also provide a precise time reference used in many applications including scientific study of earthquakes and synchronization of telecommunications networks.
The satellites also carry detectors as part of the United States Nuclear Detonation Detection System.
The system is named NAVSTAR GPS (Navigation Signal Timing and Ranging Global Positioning System). The satellite system is managed by the United States Air Force 50th Space Wing based at Schriever Air Force Base in California. Although the system is maintained by the USAF, it is free for public use.
At an altitude of 12,600 statute miles, each satellite passes over the same location on Earth twice a day. With 30 actively broadcasting satellites, orbits are arranged so that up to 10 satellites are within line of sight from almost anywhere on Earth.
The GPS receiver calculates its position by measuring the distance between itself and three or more GPS satellites. Measuring the time delay between transmission and reception of each GPS radio signal gives the distance to each satellite. The signals also carry information about the satellites' location. By determining the position of and distance to at least three satellites, the receiver can calculate its location.
 GPS satellite on public display at San Diego Aerospace Museum, California, USA |
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