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Quantum sensing is edging closer to practical deployment in defense and maritime navigation, as demonstrated by a recent trial conducted aboard the Royal Australian Navy’s MV Sycamore. The test, led by quantum technology firm Q-CTRL, focused on a new gravimetric navigation system designed to operate independently of GPS.
The trial used a quantum dual gravimeter, a device that tracks minute changes in Earth’s gravity field. By comparing these readings with known gravity maps, the system allows for precise positioning. This approach bypasses the need for satellite signals, making it particularly valuable in areas where GPS is blocked, spoofed, or otherwise unavailable.
According to Interesting Engineering, over a continuous 144-hour test at sea, the gravimeter functioned without human intervention, marking a key difference from previous lab-based quantum experiments. Installed in a single server rack within a standard communications room, the device operated using just 180 watts of power—remarkably low for its capabilities. This setup was tested under real-world maritime conditions, including engine vibrations and ship movement, which typically cause signal loss in conventional systems.
Unlike magnetic navigation or inertial systems, which can drift over time or suffer interference, the gravimetric approach offers long-term stability. In this trial, Q-CTRL’s sensor remained operational thanks to proprietary software that compensated for environmental disruptions. The company refers to this capability as “software-ruggedization,” which allowed the system to recover and maintain functionality under conditions that usually defeat lab-grade equipment.
The backdrop to this development is a growing global concern over the vulnerability of GPS. Recent disruptions have underscored the risks for both military and civilian sectors, causing interest in resilient alternatives to rise.
Gravimetric navigation is not a full GPS replacement, but trials like this one indicate it could be a viable fallback or complement in contested or denied environments. As interest in quantum technologies grows, especially in the defense sector, field-validated systems like this one are likely to draw increasing attention.
