Layering up your resilience

To get assurance on your position you need multiple inputs to your navigation system. 

• Inertial Motion Sensor unit
• Doppler velocity log unit
• Relative acoustic positioning

Dead reckoning

When navigating underwater the navigational aids get fewer. At times you may end up only reliying on your Inertial Motion Unit (IMU) for your position. For underwater navigation you need IMUs with a accuracy that is much higher than what you need above the surface.  A limitation of IMUs is that — if they don't have any input from other sensors — a small error in calculated position will accumulate exponentially. 

How jamming and spoofing threaten safe navigation

Jamming disrupts GNSS signals, limiting access to satellite-based positioning. This can leave vessels without accurate speed or location data, posing serious operational and safety risks – especially in busy shipping lanes, poor visibility conditions or unfamiliar waters.

Spoofing, on the other hand, is more insidious. By mimicking legitimate GNSS signals, attackers can trick navigation systems into misreporting the vessel’s position. Without a trusted back-up system, a ship could be unknowingly diverted off-course, putting it at risk of grounding, collision or entering restricted waters.

Although traditional gyrocompasses are immune to these signal-based attacks by design, many modern navigation systems incorporate GNSS data to enhance positioning accuracy. This creates vulnerabilities – unless paired with intelligent inertial technology.