Quantum Compass Could Free Us From Satellites For Navigation

Any GPS user who has ventured into an area with lots of obstacles that prevent satellites from being seen by their navigation unit knows the woes of satellite-based navigation. Anytime the GPS device on your dash can't see the satellites, you lose your signal. Signal loss happens under heavy tree cover, in mountain canyons, and in cities with tall buildings.

Researchers in the UK have invented something dubbed the quantum compass (quantum accelerometer) that could free us from needing satellites for navigation. Researchers say that the quantum accelerometer needs no external signals for its navigation capability. The breakthrough would also usher in an era of navigation devices for military purposes that don't rely on external signals that can be jammed by the enemy.

The quantum accelerometer comes from a UK National Quantum Technologies Programme that the UK government invested £270m into over the last five years, along with funding from the Defence Science and Technology Laboratory's Future Sensing and Situational Awareness Programme, the Engineering and Physical Sciences Research Council, and Innovate UK. The device was constructed at Imperial College London, and M Squared and is the first commercially viable quantum accelerometer capable of navigation use.

The accelerometer can measure velocity changes over time, and by combining that velocity data with the starting point of the accelerometer, a new position can be calculated. Accelerometers are common today in both laptops and smartphones, but the version in those devices are unable to be accurate over longer periods without external references. The quantum accelerometer gets its precision and accuracy by measuring the properties of supercool atoms.

At low temperatures, atoms act like both matter and waves; quantum mechanics are required to describe how the atoms move at low temperatures. That allowed the researchers to describe how the atoms move using an atom interferometer. As the atoms fall, the wave properties are affected by the acceleration of the vehicle; the accelerometer uses an "optical ruler" and can measure the minute changes very accurately. The catch right now is that the quantum accelerometer requires the use of very powerful lasers making the current version of use for ships and other large vehicles.