GPS has been in service for twenty years, but it is already showing signs of fatigue. All it takes is a tall building, a tunnel, a few kilometers underwater and the signal disappears. Not to mention when someone decides to deliberately disturb it. Researchers at Fraunhofer institutes have come up with an elegant alternative: turning flaws in synthetic diamonds into ultra-precise quantum sensors. Their magnetometer reads variations in the Earth's magnetic field like an invisible map. And it actually works: everywhere, even 1300 meters underground.
An imperfect diamond that measures everything
The technology is based on what physicists call nitrogen vacancy (NV) centers. Essentially, when a carbon atom in the diamond’s crystal lattice is replaced by a nitrogen atom, a “defect” is created that has extraordinary quantum properties. Michael Stoebe, head of the Quantum Devices unit at Fraunhofer, explains:
“These NV centers function as the smallest scanning magnets in existence, capable of precisely measuring the vector components of the Earth’s magnetic field.”
The researchers managed to reduce the size of the magnetometer by a factor of 30 in just a year. Today, the sensor is comparable in size to traditional optical magnetometers used in industry, but maintains a sensitivity in the picotesla range. The goal for next year is to further reduce the size by a factor of 5, reaching sub-picotesla sensitivity. At that point, the “old” GPS will be doomed.
How Magnetic Navigation Works with the Diamond Magnetometer
The Earth’s magnetic field, you know, is not uniform. It has distinctive regional variations that can be mapped with extreme precision. These magnetic “fingerprints” become navigational landmarks. As proven in underwater tests Conducted in the South China Sea at a depth of 1300 meters, the quantum magnetometer maintains navigation accuracy within 5 degrees compared to traditional systems.
The technology offers decisive advantages over GPS: it works underground, underwater, inside buildings and in any environment where satellite signals cannot reach. It cannot be disturbed or hacked, because it is completely passive. Michael Kunzer, project manager at Fraunhofer, emphasizes the application-oriented approach:
“We respond to the individual requirements of our systems by developing sensors with optional water cooling for stable measurements even under difficult operating conditions.”
From the lab to the real world
The path from research to practical application is accelerating rapidly. Synthetic diamonds are grown in specialized reactors at the institute, where carbon atoms are precisely replaced by nitrogen atoms. Ultrapure diamond “wafers” are currently being produced; with planned improvements, industrial-scale production could begin next year.
The military interest is evident: Frequency Electronics has received a contract from Leidos to develop NV magnetometers for navigation in “GPS-denied” environments. But civil applications, the ones I personally prefer, are equally promising.
Geological survey without drilling
The quantum magnetometer opens up new possibilities for geological exploration. It allows the precise and contactless location of underground mineral deposits, providing access to valuable resources. It can also detect unexploded ordnance over large areas, significantly reducing risks to people in the affected areas.
The collected data is converted into magnetic maps that show the location of suspicious objects, providing information on depth, shape and size. This method allows for a complete and non-invasive exploration of the areas of interest, locating even deeply buried objects.
Diamond Magnetometer, the Future That Will Bring Us Home
As we told you in this article, quantum technologies are demonstrating increasingly concrete applications. The diamond magnetometer represents an important step towards independence from satellites, offering reliable navigation in any environmental condition.
Next time you lose your GPS signal, think about imperfect diamonds: they could soon be guiding you home.
