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Modern navigation depends heavily on satellite signals, but GPS is not always available. Signals cannot reliably penetrate underground or deep underwater and can also be disrupted by interference or jamming. Vehicles operating in these environments therefore rely on inertial sensors to estimate their movement, but small measurement errors accumulate over time and gradually reduce positioning accuracy.
Researchers at the A*STAR Quantum Innovation Center have developed a new mechanical sensing platform that could eventually improve navigation without external satellite signals. At its center is a magnetically levitated, millimeter-scale rotor that can spin with exceptionally little energy loss, providing the stable motion required for sensitive gyroscope measurements.
The concept takes advantage of diamagnetic levitation, which allows the rotor to remain suspended without physical contact. Removing bearings eliminates much of the friction that normally slows a spinning object, but levitated systems face another problem: movement through magnetic fields can generate electrical eddy currents that dissipate energy.
According to TechXplore, the researchers addressed this through rotational symmetry. As the rotor spins around its central axis, it experiences nearly the same magnetic environment throughout each revolution. This greatly suppresses the eddy currents that would otherwise slow it down. According to the study, rotational energy was lost roughly 100,000 times more slowly than energy associated with the rotor’s sideways and vertical movement.
Using electrostatic forces and real-time control, the team accelerated the rotor to 930 revolutions per minute inside a high-vacuum environment. After the driving force was removed, it continued rotating for more than 10 hours. The measured dissipation rate was just 3.85 microhertz, which the researchers report as the lowest achieved for a mechanical rotor of this size.
That stability allowed the system to function as a sensitive gyroscope. It detected rotational motion as slow as 0.0065 degrees per second, placing its performance within the commercial-grade range. Modeling suggests that further improvements could eventually bring it into the more demanding navigation-grade category.
The technology could have significant defense and homeland-security applications. Military vehicles, submarines, autonomous underwater systems and underground robots may need to navigate where GNSS signals are unavailable or deliberately jammed. More stable inertial sensors could allow these platforms to maintain accurate estimates of their orientation for longer periods without relying on external positioning signals.
Importantly, the platform combines passive levitation, room-temperature operation and high-speed rotation rather than requiring cryogenic conditions. The researchers now plan to increase its rotational speed, improve stability and shrink the surrounding hardware.
The longer-term objective is an affordable navigation sensor suitable for practical deployment. If those engineering challenges can be overcome, a tiny rotor that barely slows down could provide another way for autonomous systems to keep their bearings when satellites are no longer available.
