FLC | AFRL, MIT-LL tap quantum systems to develop GPS alternative

AFRL, MIT-LL tap quantum systems to develop GPS alternative

May 6, 2020

The Air Force Research Laboratory (AFRL) and MIT Lincoln Laboratory are collaborating to develop a navigation tool that could replace a global positioning system (GPS) if it ever stops working.

“The high-level motivation is that when we don’t have GPS — and most people agree that if we have a major war, the GPS is going down — we need a different way to navigate,” said AFRL integrated photonics and optoelectronics team lead Robert Bedford.

Some alternatives such as star-finders or looking at ground features have obvious limitations. For example, the stars are not visible during the day.

The best alternative would be to navigate by sensing Earth’s magnetic field—something that may be accomplished most effectively with a magnetometer made of quantum materials. Bedford and fellow AFRL researchers Luke Bissell, Chandriker Dass, and Michael Slocum, whose work is focused on finding practical applications for the curious phenomena that occur in quantum materials, have conceptualized a magnetometer prototype being developed by MIT Lincoln Laboratory.

“They are expecting to demonstrate a prototype device within the next year or so,” said Slocum, an AFRL electronics engineer.

The magnetic field in question is not the “core field”; that is, the field generated by Earth’s iron core. It is the “crustal field.” The core field is constantly in flux. The north and south magnetic poles both wander over time. The crustal field, in contrast, is consistent and, in Bedford’s words, “impossible to spoof.”

“There is more information in the crustal field,” Bedford said. “The information is also static, unlike the core field, which changes over time. The crustal field is of a much lower magnitude, however.”

That’s why more sensitive detecting instruments are needed, the kind made possible with quantum materials.

“If you can get high enough resolution magnetic field sensors,” Bedford said, “you can take a known map of the magnetic fields of an area, then sense the magnetic fields of your present location and use the comparison to determine your exact location and what direction you’re going.”

Quantum materials provide other clear advantages.

“When using classical materials, you have to be constantly recalibrating the instruments. In quantum systems there is no need to recalibrate; there is no drift over time. You will always have an absolute measurement,” Bedford said. “The instruments would also be more compact than those using classical techniques.”