I have heard that the US Navy has recently started requiring officers in training to be able to use a sextant again, after this had been phased out after GPS became available. Seems they are spooked by the threats to the GPS system satellites, and recent jamming activities by the Russians over Norway. Scandinavian airlines operating in the affected area have issues advisories suggesting the use of dead reckoning skills as a backup.
https://www.npr.org/2016/02/22/46721...s-for-officers