[time-nuts] Chip-scale Atomic Clock !

[Brooks Shera]

The excerpt  below from GPS World refers to a Chip-scale atomic clock being developed by DARPA.  

Does anyone know what technology they might be using for such a clock?

"Atomic Clock Synchronization 
The U.S. Navy Space and Naval Warfare Systems Center San Diego is incorporating a chip-scale atomic clock into a new GPS receiver design, the Navigation Nugget. read more»The Nugget fuses a GPS software-defined receiver with an inertial measurement unit (IMU), synchronized by an onboard atomic clock, to create a positioning, navigation, and timing-sensor suite capable of withstanding impaired and threatened GPS environments. The chip-scale atomic clock is being developed by Defense Advanced Research Projects Agency. Adding an atomic clock to the GPS/IMU combination will help ground forces in canopy or jammed environments and improve vertical accuracy. A large-scale prototype Navigation Nugget is expected to be field tested in one year. Space and Naval Warfare Systems Center, www.spawar.navy.mil/sandiego/.  "



-Brooks