Using a combination of GPS and the Internet, clocks anywhere on Earth can be set to within 10ns of one another, claim US researchers.
The method makes use of a common-view disciplined oscillator (CVDO) - a device "whose frequency and time are tightly controlled to agree with a reference clock at another location, if both clocks are connected to the Internet and if both clocks are being compared to GPS satellites," said Michael Lombardi, a metrology engineer with the US National Institute of Standards and Technology (NIST).
The significance of the CVDO, said Lombardi, "is simply that you don't have to depend on GPS time."
While there is no shortage of GPS disciplined oscillators, hundreds of thousands of them according to NIST, "a CVDO potentially provides more versatility. It would allow a telecommunications network to synchronise all of its clocks to a different reference than GPS", Lombardi said. "If GPS time is wrong, the CVDO will still be correct as long as its reference clock is right."
The team has published the method in A common-view disciplined oscillator, a paper in the Review of Scientific Instruments, published by the American Institute of Physics.