To obtain the maximum accuracy from your Cesium clock, there must be no residual magnetic field which could affect the oscillation of the cesium beam. To ensure this, the old Hewlett-Packard applied their legendary over-engineering skills to this de-gausser, which applies a precisely calculated exponentially decreasing alternating magnetic field to coils engineered into the cesium ion tube. The test equipment required for this procedure weighs even more than the atomic clock.
Where does the sub go for its ‘treatment’? Underwater? Does this device move to a drydock?
If memory serves the boat just surfaces inside the mechanism. Or more likely it is gently guided into the mechanism from one of the ends. I wasn’t a bubblehead so I am not exactly sure. I served on a Destroyer, also known as a target.
Usually a moving target, I imagine.
Depends on the helmsman!