The
Global Positioning System (GPS) is made up of 24 satellites orbiting the
globe at an altitude of 28,000 km. The GPS system is handled by the US
Department of Defense and was basically built to give moving subs an
exact position when firing missiles at small specific targets like
Al-Qaeda midgets (just kidding).
To prevent the location data from being used by the
enemy, the GPS gave an intentional error of around 50 meters/150ft when introduced to the public.
However, since May 200, that error has been removed.
A small handheld GPS unit typically gives the position with an accuracy of
15 meter/50 ft, and when using DGPS (Differential GPS), sailors have
an accuracy of 3 meter/10 ft - or less than the width of the yacht.
Satellites are transmitting radio signals to GPS receivers with the
speed of light. Receiving signals from 3 satellites simultaneously, the
GPS receiver calculates the position by triangulation. The accuracy is
expected to rise even further with signals generated by increasingly more
satellites.
The
Global Positioning System (GPS) is made up of 24 satellites orbiting the
globe at an altitude of 28,000 km. The GPS system is handled by the US
Department of Defense and was basically built to give moving subs an
exact position when firing missiles at small specific targets like
Al-Qaeda midgets (just kidding).