The data sheet for the GPS (it's a Neo-6m, but I don't think the specific RX module matters, as NMEA is a general standard) just says it uses the "standard NMEA messages", but none of them return the timestamp data on a per-satellite basis.
So a GPS receiver can generate strings outside the NMEA standard it's using?
I dont understand really what is to be gained by doing the calculations the GPS perfoms so well,
cm positional accuracy with RTK.
RTK relies on me operating within range of an RTCM station and the nearest one to me is about 50 miles away