GMDSS Maintainer: Element 9

1. A A fiber-optic coil and three accelerometers determine the speed of rotation of the earth.
2. B Two fiber-optic coils with one accelerometer and a level sensor determine the direction of true north.
3. C Three fiber-optic coils with a dual accelerometer and a yaw detector determines the direction of true north.
4. D Three fiber-optic coils and a dual-axis electronic level sensor determine the direction of true north.

Tip: press A-D to answer