Multimedia Gallery
The shape of the Earth, known as a geoid, is shown here with colors and exaggerated heights from multiple points of view.
This is the master clock used at the Goldstone, California, Deep Space Network station from about 1983 to 2006.
Aircraft equipment interprets time signals received from a network of satellites.
The image shows accuracy to within a radius of about 20 feet (6 meters).
The image shows accuracy to within a radius of about 148 feet (45 meters).
This artist's rendition of a new generation of GPS satellites.
GPS satellites are positioned in precise, circular orbits 18,000 kilometers (11,000 miles) above the Earth. They orbit once every 12 hours.
Length: 7 Minutes, 3 Seconds
The first military GPS five-channel receiver, weighing 270 pounds.
