Submarine navigation uses/used Very Low Frequency radio waves which can penetrate under water.
No, not correct. The Omega system was the precursor to GPS. It does not work underwater.
When GPS was initiated 2 years later, the Omega Towers and system were abandoned.
radio waves nor GPS penetrate water. The systems use sound navigation (SONAR) for navigation. Certain systems place pingers, which provide location underwater, but this is very, very new.
Its all up to the inertial system..