New method developed for synchronizing clocks

July 20, 2010

Maintaining the correct time is no longer just a matter of keeping your watch wound -- especially when it comes to computers, telecommunications, and other complex systems. The clocks in these devices must stay accurate to within nanoseconds because their oscillators -- objects, like quartz crystals, which repeat the same motion over and over again -- are synchronized to agree with the clocks on board Global Positioning System (GPS) satellites.

In the journal Review of Scientific Instruments, which is published by the American Institute of Physics, researchers report on a new way to accurately synchronize clocks. The new method uses both GPS and the Internet to set clocks within 10 nanoseconds of a reference clock located anywhere on Earth.

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," says Michael Lombardi, a metrology engineer with the National Institute of Standards and Technology (NIST), and coauthor of the paper along with Aaron Dahlen of the United States Coast Guard.

The significance of the CVDO, says Lombardi, "is simply that you don't have to depend on GPS time." While there is no shortage of GPS disciplined oscillators -- "the in North America probably owns several hundred thousand of them," Lombardi says -- "a CVDO potentially provides more versatility. It would allow a telecommunications network to synchronize all of its clocks to a different reference than GPS, such as the NIST standard" -- the that keeps the official time for the United States. "If GPS time is wrong, the CVDO will still be correct as long as its reference clock is right."

Explore further: Chip-scale atomic clock

More information: The article, "A common-view disciplined oscillator" by Michael A. Lombardi and Aaron P. Dahlen was published online in the journal Review of Scientific Instruments on May 2, 2010. See: rsi.aip.org/rsinak/v81/i5/p055110_s1

Related Stories

Chip-scale atomic clock

August 28, 2004

The heart of a minuscule atomic clock---believed to be 100 times smaller than any other atomic clock---has been demonstrated by scientists at the Commerce Department's National Institute of Standards and Technology (NIST), ...

Atomic clock signals may be best shared by fiber-optics

March 2, 2007

Time and frequency information can be transferred between laboratories or to other users in several ways, often using the Global Positioning System (GPS). But today's best atomic clocks are so accurate—neither gaining nor ...

Galileo rubidium clocks – a year of in-orbit experience

May 21, 2007

Europe’s first satellite-borne rubidium clocks have been in orbit for over a year. There is good news for the building of the Galileo system: the results obtained from GIOVE-A’s first year of operations show performance ...

Time is money: SIM time network has far-reaching benefits

May 28, 2010

Clocks in the Americas and the Caribbean Islands are now ticking in unison thanks to the work of the Sistema Interamericano de Metrologia (SIM), a regional metrology organization that works to promote accurate measurements ...

Recommended for you

Seeing quantum motion

August 28, 2015

Consider the pendulum of a grandfather clock. If you forget to wind it, you will eventually find the pendulum at rest, unmoving. However, this simple observation is only valid at the level of classical physics—the laws ...

A little light interaction leaves quantum physicists beaming

August 24, 2015

A team of physicists at the University of Toronto (U of T) have taken a step toward making the essential building block of quantum computers out of pure light. Their advance, described in a paper published this week in Nature ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.