GPS beacons would be stupidly expensive, as you'd need tens of thousands of them per city, and each one of them would need a very accurate atomic clock.
It would make far more sense (but still unviable) to go for Eurobalise-style RFID tags embedded in the road surface.
>you'd need tens of thousands of them per city
I was thinking more find a tall building and throw a single one there. Or maybe tallest 3.
As I understand it even a small number of extra satellites with line of sight can improve results a fair bit.
So aiming at low hanging fruit rather than blanket city
>very accurate atomic clock.
Indeed, but I'd think managing that on ground is easier than in space.
https://en.wikipedia.org/wiki/Eurobalise Cool.
no, you arn't understanding. Those beacons would just be fixed places that know what their position is according to the GPS network.
You're tihnking of someone tkaing a GPS sattilite and putting it somewhere.