NIST Unveils Chip-scale Atomic Clock

grumling writes "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), opening the door to atomically precise timekeeping in portable, battery-powered devices for secure wireless communications, more precise navigation and other applications. "

Comments

OK, so when do I get one in my PC...

[Atrax]

... so my clock doesn't drift by like five minutes a day, necessitating a daily ping to the USNO time servers? anyone?

Great for GPS

[DustMagnet]

With a atomic clock in a GPS you no longer need to solve for time, so you can get the same quality position with one less satellite. There are times where this could make a huge difference.

Re:Great for GPS

[Detritus]

The Navy has been using atomic clocks for decades. Much of the technology in GPS can be traced back to early Navy programs for satellite assisted navigation. When you launch an ICBM from a submarine, you need a very accurate fix on the position of the submarine. Atomic clocks are also as timing references for secure communications links.

Re:Great for GPS

[Rich0]

Ok, first a clarification, and then a possible alternative implementation of GPS with fewer limitations if you can assume the receiver knows the time:

First - if you have only two satellites in the present system, the solution to the distance equation is approximately a hyperbola (it would be exactly one for a flat earth). Three satellites gives you three hyperbolas, which intersect at one point. (Remember, a hyberbola is the set of points where the difference between the distance from the point to two foci is a constant.)

However, you don't have to use difference in time to implement a GPS-like system. A more direct solution is measuring absolute time to arrival for each satellite signal. This requires an atomic clock in the receiver - which is why they don't generally do it this way. If you measure absolute time to arrival you get a sphere around each satellite you receive signal from. With two satellites the intersection is a circle, but only two points of that circle lie on the surface of the earth. If you have even a remote idea of where you are (within 1000 miles or so), you should be able to figure out which one you're at. since the two points might literally be separated by more than 1000-2000 miles.

So, the two satellite system might have some use - especially if the software is smart and keeps track of state. For instance, if you are a bomb decending to a target you would use as many satellites as you can - probably 3-4 most of the time. However, if you lost all but 2 as you got close to the ground and some jamming, you can probably bet that you didn't change position much, and so you can pick the closest solution and still have some useful guidance data. So, an atomic clock would be useful for more accurate GPS...

Could this be the end of NTP?

[feronti]

I mean, if every device has its own atomic clock, the only time you'd have to synchronize them would be when you bring them up, unless you were doing some kind of scientific work that requires ultra-accurate timekeeping. Most other applications (I'm thinking Kerberos, remote logging, etc) would only need to be synchronized to the second (or even less) to be useful.

Another interesting home networking gadget

[starbird]

When can I buy a netgear networkable home atomic clock box? Plug it in to your network, and use it to update the times on all your systems, instead of pinging NTP servers.

Or put it on a pci card, I can just put it in my router box.

Gravity

[Anonymous Writer]

Since atomic clocks can be used to measure effects of gravity, it would be interesting to see how mass producing atomic clock chips could be used to create maps of gravity, seeing how they can be used to reveal geological information.