These can help against GPS spoofing / jamming by identifying false signals and allowing rapid resynchronization:<p><a href="https://www.army.mil/article/88361/Miniaturized_atomic_clock_to_support_Soldiers_in_absence_of_GPS/" rel="nofollow">https://www.army.mil/article/88361/Miniaturized_atomic_clock...</a><p>Also related, NASA has a spaceborne atomic clock in testing that, if it works, will make space navigation much more efficient:
<a href="https://www.nasa.gov/mission_pages/tdm/clock/index.html" rel="nofollow">https://www.nasa.gov/mission_pages/tdm/clock/index.html</a>
Here it is, next to a coin, for scale:<p><a href="https://www.microchip.com/en-us/products/clock-and-timing/atomic-clocks/_jcr_content/root/responsivegrid/container/cardgrid/card1/image.coreimg.png/1606931390716/r1-v1-200106-ftd-graph-csac-fig1.png" rel="nofollow">https://www.microchip.com/en-us/products/clock-and-timing/at...</a>
Instead of a beam of Cesium atoms being sensed with microwaves, this has a vapor cell sensed with microwave modulated light. This eliminates the finite lifespan previously associated with Cesium Beam atomic clocks.<p>Unlike Rubidium references, the light is supplied by a solid state laser, eliminating another huge power sink.<p>I expect these devices have a practically infinite life. What an amazing set of innovations.
If someone had a celestial database, and a telescope, how accurately could one determine their position on earth using this device? Assuming no GPS satellites are available.
We looked at using these in a previous job that had a very tight tolerance on RF frequency tolerance. Vibration tolerance makes the use of crystals difficult.
Unfortunately, the phase noise of this device wasn't good enough to be the frequency source for the radio itself, so we would have had to use the CSAC to discipline a tcxo. By the time we did that, it really wasn't that advantageous.
It looks like they have a low-noise option that includes a tcxo now, but (no surprise), it doesn't appear to have a operating vibration spec.
If there are any current (or ex-) Symmetricom employees reading this, then I'd love to hear about your work. I have a profound interest in the domain of high-precision timekeeping.