Your phone can do a lot with just the cell towers for navigation. The towers themselves would lose GPS signal but they are stationary, they should be able to pu

Your phone can do a lot with just the cell towers for navigation. The towers themselves would lose GPS signal but they are stationary, they should be able to pump out location despite the loss of signal. The guy out in the middle of nowhere might be screwed but there always should be a backup navigational aid when you are that far out. A GNSS blackout would be more of an issue for ships and planes. Both can get by in most cases with a GPS blackout using beacons, dead-reckoning, maps, and other old-school techniques. However, a major solar storm could cause issues with all of the navigational instruments (radios, compasses), you might be limited to just using a sextant and a precise clock.