Technology
Submarine Navigation Systems
Quick fact
Submarines rely on inertial navigation systems (INS) that measure acceleration and rotation to calculate position, but they must periodically 'reset' using sonar, periscope sightings, or even celestial navigation to correct for small errors that accumulate over time.
Why this is interesting
How does a submarine know exactly where it is underwater, where GPS signals can't reach? The answer requires an ingenious blend of physics and mathematics.