Some A/C INS systems, the Litton ones spring to mind, have an installed Nav database and automatically update the Nav Computer part of the system via DME/DME. I think they have to have input from two separate, valid, ground stations less than 200 miles range to do this and obviously need a nav database to locate beacons. Certainly I am currently maintaining a DC10 that the crews constantly complain is not updating, and have had this in the dim and distant with a 727, both Litton INS equipped.