VPSs are much more effective at navigation at ground level in cities compared to GPS because of multi-path interference.

However that data has a half life and needs to be refreshed.

For flying drones, ground level data is really not that useful. mainly because you can't see it, because its obscured by trees, building and clouds.

But, this is not a new thing. Google, Apple, facebook and niantic all have VPSs as do a bunch of other startups.

For Drones you will probably need SLAM to capture the map, and then once you have the initial map, you can keep it updated.

You can experiment at home using https://github.com/colmap