Q-CTRL has reported what it describes as the first fully GNSS-independent maritime navigation demonstration to use a quantum gravimeter. The company says it corrected inertial navigation over an 83-km area in the Coral Sea off the east coast of Australia.
The trials were run aboard the research vessel MV Miss Rankin during a week-long campaign north of Cairns. Using its Ironstone Opal platform, Q-CTRL performed autonomous gravity mapping and gravimetric navigation with no satellite input in the measurement chain, with about 1 nm of positioning accuracy. The company reports that figure as more than ten times better than the navigation-grade inertial backup used as a comparison.
The technique, which Q-CTRL calls GravNav, measures the small spatial variations in Earth’s gravity field and matches them against a satellite-derived gravity anomaly map to bound the drift that accumulates in any inertial navigation system. It extends the company’s earlier MagNav work, which uses magnetic-field signatures for the same map-matching approach. Q-CTRL positions gravimetric navigation as better suited to the ocean because gravity maps at sea are more widely available than comparable magnetic survey data. And as the sensor doesn’t transmit or receive radio signals, it cannot be jammed or spoofed and can function day or night in any visibility.
Gravity-aided navigation has been around for decades, but Q-CTRL’s approach needs no GPS signal, no periodic recalibration, and no special infrastructure. The company attributes this to what it terms software-ruggedized quantum sensing, as the instrument pairs an atomic gravimeter with a classical accelerometer for bias stabilization, and AI-based control software holds the sensor stable under open-ocean motion.
Conventional cold-atom gravimeters typically require active temperature control, gyroscopic motion stabilization, and frequent manual recalibration. Q-CTRL installed the unit in an unconditioned passenger cabin and ran it autonomously, with the company reporting comparable performance between gimbaled and rigid strapdown mounting. The authors identify reducing the sensor’s size, weight, and power below the range of high-performing classical maritime systems as the next step toward wider unmanned deployment.
The demonstration lands amid rising interference with satellite navigation. Citing figures from maritime intelligence firm Windward, Q-CTRL says 978,000 GPS jamming events were logged worldwide in the first quarter of 2026, with 98% of them in the Middle East and affecting more than 1,100 vessels. Deliberate jamming and spoofing around the Strait of Hormuz have disrupted shipping across the region, and tankers have run aground after undetected spoofing.
Q-CTRL’s navigation work has drawn interest from the defense community including contracts and engagements with DARPA, the U.S. Defense Innovation Unit, the Australian Department of Defense, the UK Royal Navy, and other AUKUS partners. Its April 2025 MagNav trials on ground and airborne platforms were among Time magazine’s Best Inventions of 2025.