The application that Bedford and Slocum are investigating is to create a navigation tool that could replace the GPS if it ever stops working.
“The high-level motivation,” said Bedford, “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.”
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.
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,” said Bedford. “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,” said Bedford, “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 can provide that type of resolution. Quantum materials also provide another clear advantage.
“When using classical materials,” said Bedford, “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.”
But quantum systems have yet another benefit over classical systems.
“The instruments would also be more compact than those using classical techniques,” said Bedford.
Although AFRL is not working on a prototype in-house, it is funding the Massachusetts Institute of Technology Lincoln Laboratory, which is working on a magnetometer prototype.
“They are expecting to demonstrate a prototype device within the next year or so,” said Dr. Michael Slocum, electronics engineer.
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