Before revision: NAVSAT Terrestrial radio-based navigation systems; largely superseded by satellite systems LORAN—no longer in use CHAYKA, the Russian counterpart of LORAN OMEGA, the Western counterpart of the Alpha Navigation System , no longer in use Alpha, the Russian counterpart of the Omega Navigation System Celestial navigation using the periscope, or sextant—seldom used anymore due to advancement in technology Radar navigation; radar signals are easily detected so radar is normally only used in friendly waters entering and exiting ports.
After revision: NAVSAT Terrestrial radio-based navigation systems; largely superseded by satellite systems LORAN—no longer in use CHAYKA, the Russian counterpart of LORAN OMEGA, Western very low frequency global-range hyperbolic radio navigation system , no longer in use Alpha, the Russian counterpart of the Omega Navigation System Celestial navigation using the periscope, or sextant—seldom used anymore due to advancement in technology Radar navigation; radar signals are easily detected so radar is normally only used in friendly waters entering and exiting ports.