I know that the F/A-18C is equiped with a rotary switch for inertial alignment. The switch has two positions, one for ground and the other for carrier operations. Leaving aside the GPS/GNSS, I wonder how is the alignment process in a moving vessel. I'm thinking in the old good days of Phantoms, A-4's and all other Navy aircrafts of the fifties and sixties where GPS was not yet implemented. How are vessel movement errors corrected?
The aircraft carrier has its own inertial navigation system, (SINS - Ship's Inertial Navigation System) and this information is transmitted to each individual aircraft INS by either cable or datalink.
From the EA-6B NATOPS flight manual of the Mid-1990s, pre-GPS era:
18.104.22.168 Carrier Alignment requires ship's movement information as well as present position. This information must be supplied by either SINS or manual entry. When a carrier alignment is called for, the system checks that the data link is on. If this is true it is assumed that an automatic alignment is intended. If the data link is off or in test a manual alignment is assumed. The CDI then provides cues for the type of intended alignment that is assumed.
From there it goes into more detailed procedures. There is no information about preferred use of UHF data link vs cable other than a mention that on the CDI (Control Display Indicator) there will be an indication of either "CV UHF" (data link) or "CBL" if alignment information is being received via cable.
Most times at man-up the plane captains will have the alignment started, or the front seat NFO would start the alignment during preflight. Use of either UHF Data link or cable depended mainly parking location and number of available cables at that location, and speed/reliability of the UHF signal. Generally the split was random, and 50/50.
CV Manual alignments were least common, least desired, and only performed when SINS information was not available. They required more work making manual inputs, (of which ship's heading would need to updated if the ship was turning into the wind for launch, which it always did!) took longer, and they were less accurate.