Quantum positioning system steps in when GPS fails

The mention that this is based on laser-cooled atoms, with no further details, is a tad frustrating. In grad school I worked on a laser-cooled atom interferometer, which could be used as an inertial sensor. In principle, at least, since the device I worked on was relatively big; the vacuum system was an “L” that was at about a meter in the short dimension and there was a large optical table to generate the laser light. There is more than one way to build such a device, though, and these processes can be made much smaller with engineering effort, so the lack of detail is disappointing.