Originally developed in the 1970s for use by US armed forces, the Global Positioning System (GPS) network of 30-plus satellites has since found uses in everything from archaeological surveys to self-driving cars.
In 2003, physicist Dr Ivan Getting and engineer Col Bradford Parkinson were awarded the prestigious Draper Prize by the US National Academy of Engineering for making GPS a reality. But while no one disputes the importance of their role, neither were responsible for the key to the success of GPS: fitting each satellite with an incredibly accurate ‘atomic clock’, enabling locations to be pinned down to a few centimetres.
In the late 1950s, Getting and his team were working on Transit, a satellite network whose radio transmissions could be used to fix locations on Earth. The technique needed accurate timekeeping, but the quartz clocks being used weren’t reliable enough.
In 1964 the US Navy began work on the Timation programme, based on the radical concept of a network of orbiting atomic clocks, which keep time using more stable quantum effects. The Timation programme was masterminded by Dr Roger Easton at the Naval Research Laboratory, and Parkinson led the drive to get the technology out of the lab and into orbit. But not until 2010 did Easton join the others in the US National Inventors Hall of Fame.
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