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How could submarines navigate beneath polar ice using inertial guidance?
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Officers on a passenger ship using charts for navigation.
Inertial guidance systems allow submarines to navigate beneath polar ice by functioning as sophisticated dead-reckoning devices that operate independently of external signals.12
The system relies on three primary components: gyroscopes, accelerometers, and a computer. The process works as follows:2
- Measurement: Accelerometers measure the craft's acceleration in three dimensions, while gyroscopes establish a stable frame of reference or sense the vehicle's turning rates.12
- Integration: The onboard computer performs two successive numerical integrations on the acceleration data. First, it integrates acceleration to determine the submarine's current velocity, then it integrates that velocity to calculate the submarine's current position.12
- Guidance: This calculated position is continuously compared against a pre-programmed course to maintain the desired trajectory.2
Because these systems are self-contained, they enable nuclear-powered submarines to traverse the north polar ice cap without needing to surface for external navigation fixes, maintaining high accuracy with errors of less than a mile per week.12