Atomic Clocks?

[YT2095]

I watched a program that other day that explained how the GPS network operates. and the sat array that we have up there (20+ birds) each has an onboard atomic clock.

 

now since Weight is an issue and Very costly, I`m curious as to how big these clocks are?

 

I have in my head that atomic clocks are like huge fridge/freezers in size, I expect that I`m probably wrong though.

 

also, how much would a "small" atomic clock cost to buy?

[insane_alien]

according to ikipedia that have made chip scale atomic clocks, there is a picture of one here

http://en.wikipedia.org/wiki/Atomic_clock

 

not sure how much it would cost but i imagine it would be pretty pricey.

[swansont]

Chipscale clocks are still in the development phase. Their precision isn't up to the level that they'd be useful on GPS satellites; they are more for a person in the field. Having a decent idea of your time reduces the acquisition time of GPS signals, since the receiver knows what part of the code to look at. Small in this case is important so you can carry it, and so it doesn't draw much power.

 

The GPS clocks can be both cesium and rubidium clocks, or in the case of the Galileo system, they will be rubidium clocks and a hydrogen maser.

 

Picture of a space-qualified cesium clock

http://www.symmsda.com/products/4415.asp

 

and another (this may be a rubidium clock)

http://www.kowoma.de/en/gps/satellites.htm

 

A new non-space qualified cesium clock is about $30k - $50k. I strongly suspect smaller and/or space qualified would be significantly more expensive, since you pay extra for those features.

[Pangloss]

I sense a new purchase in YT's future.

[the tree]

Sawnsont, IIRC from your blog you said that "light" clocks that are in development are well, better. Are they (in the near future) going to be more cost (and weight) effective?

[swansont]

Sawnsont, IIRC from your blog you said that "light" clocks that are in development are well, better. Are they (in the near future) going to be more cost (and weight) effective?

 

More cost, yes. Right now they are "boutique" items; more-or-less hand-crafted in the sense that while many of the parts are commercially available, the combination of them is not, and lots of work has to go into getting everything to work. Much like the case with atomic fountains, you have to make specialized circuitry and components. And there is a lot of specialized care and feeding.

 

In a couple of years I should be in a position to estimate how much an optical clock costs, but I think the laser that gets you started is a couple hundred thousand dollars.