What if ships could navigate without GPS? Q-CTRL has demonstrated quantum gravimetric navigation at sea, maintaining positioning accuracy within one nautical mile.
Q-CTRL’s Ironstone Opal quantum navigation system has demonstrated GPS-free navigation of a maritime vessel during field trials in the Coral Sea off Australia’s east coast. The system used a quantum gravimeter to map variations in Earth’s gravitational field and achieved positioning accuracy of one nautical mile over the mission duration.
The system works by continuously measuring small variations in Earth’s gravity and matching these measurements against existing gravity maps. Unlike satellite-based navigation, this approach does not require external radio signals, allowing the vessel to continue positioning when GNSS signals are unavailable or disrupted.
The demonstration combines a quantum gravimeter with an inertial navigation system. Gravity measurements provide corrections to the inertial system, helping maintain positioning accuracy over time without requiring periodic sensor recalibration.
A key part of the system is the company’s software-ruggedised quantum sensor technology. AI-powered software stabilises the quantum sensor against environmental disturbances, allowing it to operate during maritime movement without additional temperature control, gyroscopic motion stabilisation or special installation infrastructure. During the trials, the system was installed inside a passenger cabin and operated autonomously.
The approach is particularly suited to maritime navigation because detailed gravity maps are available across ocean regions. The company said the demonstration also represents the first open-field demonstration of quantum gravimetric navigation that does not rely on GPS signals, periodic sensor recalibration or specialised installation infrastructure.
The demonstration builds on the company’s earlier MagNav system, which uses variations in Earth’s magnetic field for GPS-free navigation.
“Gravity sensing and map matching is the only passive Alt-Nav technology that is global in extent and is impossible to jam or to spoof,” says Jason Ralph, Professor of Electrical Engineering and Electronics at the University of Liverpool.
