Hi @AdamJP, I think that you are writing about building a system that is similar to a standard extension to systems like GPS. The technology for GPS is called Differential GPS, https://en.wikipedia.org/wiki/Differential_GPS.
A network of fixed ground-stations with very accurately surveyed locations continually listen to GPS and report the error between their real location and their GPS location. This is then made available to other stations as a correction factor that continually changes for location and time.
I have worked a lot on marine vessels and this is used on all large vessels to correct their location. It is available as a commercial service over radio and satellite from companies like Fugro, https://en.wikipedia.org/wiki/Fugro - for $$$.
So… in my opinion, if you needed very accurate correction to location services you could do something similar over LoRaWAN.
Note: Differential GPS is also used as a security measure in case the GPS system is compromised, etc. This allows a switch to manual navigation for marine vessels. Something similar will be needed for autonomous vehicles.