Such networks exist and make their data public. I think the equivalent you’re looking for is like LightningMaps, where there is real time reporting of observations instead of having to process recorded data to look back in time?

https://geodesy.noaa.gov/CORS_Map/

https://www.e-education.psu.edu/geog862/node/1830

https://learn.sparkfun.com/tutorials/how-to-build-a-diy-gnss...