How I understand it, RTK comes into play you want to get very precise location on a moving vehicle. To make the location reading more precise you need to take i

How I understand it, RTK comes into play you want to get very precise location on a moving vehicle. To make the location reading more precise you need to take it over some time. To average it while moving you need to know _how_ you're moving. Therefore the need for RTK. The RTK position is then combined with the measured error (measured near that location), because GPS is precise but not accurate enough on it's own. Without correction a stationary point slowly drifts around a bit (accuracy: roughly 0.1-1 meters). The correction is called differential gps, and you can provide it yourself with a base station, or use a service that does just gives it to you (from their network of error measuring base stations), see NTRIP. The accuracy with correction can be greater than 0.01m