I think you'd have more problems with battery range than with navigation in that specific case, although certainly a cheap, reliable navigation system that work

I think you'd have more problems with battery range than with navigation in that specific case, although certainly a cheap, reliable navigation system that works in GPS denied environments would be a huge boon for Ukraine right now. Perhaps the same tricks that are currently done to neuter civilian GPS could be applied. Although as I understand it, those are mainly intended to prevent you from making a cruise or ballistic missile from a box of parts by preventing high speed and high altitude service. Those are likely becoming insufficient in the era of drones, where you don't really need to go outside of civilian GPS approved envelope. Or maybe it will be like cheap IR cameras. The best cheap IR cameras are currently imported from China, because US companies are prevented from creating anything comparable for the civilian market by ITAR.