Government Funded Atomic Clock On a Chip 134
An anonymous reader writes "Today most applications that require accurate atomic clock readings — from sorting separately routed telecommunications packets to timing simultaneous demolition charges — usually refer to signals from global positioning systems (GPS). For applications where GPS is unavailable, such as indoors, underground, undersea or on the battlefield where electronic jamming is present, large, heavy, power hungry hardware atomic clocks were needed. Now an atomic clock-on-a-chip is available that is the result of 10 years of government-funded research and development. The chip is not cheap — $1,500 — but it costs less than conventional atomic clocks and the price is sure to go down as manufacturing gears up to meet demand from military applications."
frequency hopping and better navigation. (Score:5, Interesting)
I can think of two to uses off the top of my head. The first is for really fast frequency hopping radios. The rate at which they can hop from one to the next has got to be in some measure limited to how accurate the clock they use is.
And the next one would be improved navigation. You could use these with ground stations and provide extremely accurate navigation and you could use more powerful transmitters so they would be harder to jam.
Now if they could uses these to put a time signature on every radio, tv, and cell tower You could improve navigation in areas where GPS doesn't work so well. Like in buildings. cites with lots of tall buildings, or areas with lots of tree cover.
No! not Symmetricon! (Score:4, Interesting)
Re:frequency hopping and better navigation. (Score:4, Interesting)
Yup. One of the barriers to postprocessing is local clock inaccuracy - so having a local atomic clock would be great for survey-grade GPS units.
And as you stated - if receiver clock offset is 0, then you don't need to solve for it, and can get 3D position with 3 sats instead of 4. The actual effect of an inaccurate clock on the error is harder to determine - I have a feeling that with a reasonable quality local crystal oscillator (good enough not to cause cycle slips in the measured carrier phase, etc.) it's insignificant compared to ionospheric error and RF noise in the pseudoranges, along with multipath. The new L2C civilian signal will help some of these issues.
A highly accurate local clock might also make dead reckoning in a blockage situation (urban canyons, tunnels, etc) and signal reacquisition after blockage goes away faster.