Page 48: of Marine Technology Magazine (September 2024)

Feature: Gyroscopes

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GYROSCOPES

A new generation of ? ber optic gyroscopes is taking the accuracy of inertial navigation systems higher and the payload lower.

Exail

Diagram of inertial navigation system ? ber optic gyroscope (FOG) can now weigh less than three kilograms, less than two kilograms even, and be less than 200mm in diameter. As their host AUVs themselves shrink, FOGs are following suit, and as

A the AUVs go deeper and perform a wider range of data collection tasks, FOGs continue to be part of the GNSS- denied navigational systems that enable them to do it.

The FOG sensors in an inertial navigation system measure changes in orientation of the AUV to support navigation by

Exail dead reckoning as satellite systems such as GPS are not avail-

Phins 9 Compact able subsea. FOGs operate by monitoring the difference in weighs 1.2kg and propagation time between beams of light traveling in clock- features a power wise and counterclockwise directions about a closed optical consumption of path. Two beams of light are sent in opposite directions in less than 7W.

a ? ber optic coil. As the vehicle rotates, the beam travelling 48 September/October 2024

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