In February, a small aircraft flew 300 miles through the skies, guided only by Earth’s magnetic field. How so? Onboard was a new device called MagNav, developed by Australian startup Q-CTRL, and it may mark the beginning of a new era in navigation.

For decades, the Global Positioning System (aka GPS) has been the invisible hand guiding our phones, our planes, and even our armies. But as GPS jamming and spoofing incidents surge — including a wave of disruptions over the Atlantic in 2024 — researchers and governments have been racing to find alternatives. Now, Q-CTRL says it has found one: a quantum-based navigation system so precise it leaves traditional GPS in the dust.

The Promise of Magnetic Maps

Modern navigation leans heavily on the constellation of satellites that make up the Global Navigation Satellite System (GNSS), including the familiar GPS. But GNSS is vulnerable. It can be jammed or spoofed, and it offers poor coverage near the poles and under certain conditions. When satellite signals fail, navigators often turn to inertial systems, which measure accelerations and rotations to estimate position. Over time, though, errors accumulate.

Other alternatives to GNSS are few and flawed. Radar and LIDAR can reveal a navigator’s location. Optical methods like terrain recognition depend on clear skies and recognizable landmarks.

But magnetic anomaly navigation—essentially using the subtle fingerprints in Earth’s crustal magnetic field—offers a passive, weatherproof solution.

Earth’s crust is peppered with magnetic quirks—tiny deviations from the planet’s broad magnetic field—that stay stable over time. With a sensitive enough magnetometer—a sensitive quantum sensor—and good maps, it should be possible to determine position by reading these magnetic signatures like a fingerprint. Until now, the problem has been practical: magnetometers were too noisy, maps too coarse, and vehicle systems introduced overwhelming interference.

Reading These ‘Fingerprints’

Enter MagNav. Developed under Q-CTRL’s broader Ironstone Opal initiative, it is a magnetometer sensitive enough to detect the faintest twists in Earth’s magnetic field. These sensors use trapped atoms or “tiny compass needles which can be read out by laser beams,” according to Michael Biercuk, Q-CTRL’s CEO and founder.

Instead of relying on satellite signals, the MagNav system reads the magnetic landscape below the aircraft. Earth’s magnetic field changes subtly depending on where you are, shaped by variations in the planet’s crust. MagNav captures these subtle differences and compares them against a detailed magnetic map, using AI to filter out background noise from the aircraft’s own electronics.

This approach offers a huge advantage: it’s entirely passive. The system does not emit any detectable signal because there’s no constant triangulation with satellites. In other words, it can’t be jammed or detected.

Quantum Leap in Navigation

The researchers also designed the system to be small and practical, capable of fitting onto a drone or into a commercial airliner’s avionics bay. Flight trials conducted in February 2025 put the system through its paces across more than 6,700 kilometers of flying at altitudes up to 19,000 feet. Ground tests were conducted with the equipment strapped into a rental van.

The results were positive. During a flight at 3,600 feet, the quantum-assisted MagNav achieved a final positioning error of just 22 meters—only 0.006% of the flight distance—beating a high-grade inertial navigation system (INS) by a factor of 15.

Even in more challenging environments, such as operating inside a magnetically noisy aircraft fuselage, the system consistently outperformed the inertial alternative, delivering between 11 to 38 times better accuracy.

A Backup for GPS Built for an Uncertain Future

Inertial navigation systems, the old fallback for aircraft and military vehicles, track motion from a known starting point. But their errors build over time, often drifting miles off course after just a few minutes without GPS support. In contrast, Q-CTRL’s MagNav system maintained accuracy across an entire 300-mile (483-kilometer) journey.

The stakes could not be higher. In today’s world, GPS is a single point of failure. Without it, planes can get lost, military operations can falter, and critical logistics can grind to a halt. As GPS jamming becomes increasingly common — whether through rogue state actors, cyberattacks, or technical failures — having a reliable alternative has become a necessity.

However, MagNav depends heavily on the availability of detailed magnetic maps. “Navigation on the map without strong magnetic features is very difficult,” Jukić told New Scientist. “It is like navigating on the open sea without any visual landmarks or a compass.” In areas with sparse magnetic features, the system’s accuracy could suffer.

Recognizing both the promise and the limitations, Q-CTRL is already moving ahead. The company is collaborating with the Australian Department of Defence, the UK Royal Navy, the US Department of Defense, and Airbus to refine and deploy MagNav on military drones and eventually commercial aircraft.

The study was published in the preprint server arXiv.