There's technology now that matches local satellite/aerial images against the imagery that a drone or cruise missile sees to replace the GPS chip.

For fairly obvious reasons, militaries that have it would rather it stay in their hands, for fear of creating a non-state peer competitor that can do cheap long-range strikes on strategic targets.

It's fairly likely it'll fall into private hands anyway though, because anyone who can afford the prices for commercial satellite imagery could build such a thing.