Sub cm horizontal precision has been commercially available since at least 1999. Differential GPS usually implies a fixed base station and a fixed receiver. R

Sub cm horizontal precision has been commercially available since at least 1999. Differential GPS usually implies a fixed base station and a fixed receiver. RTK implies the receiver can be in motion. It was central to Trimble products. https://insidegnss.com/generating-carrier-phase-measurements/ https://insidegnss.com/generating-carrier-phase-measurements... https://www.gpsworld.com/innovation-carrier-phase-rf-ranging/ https://www.gpsworld.com/innovation-carrier-phase-rf-ranging... https://www.vectornav.com/resources/inertial-navigation-primer/theory-of-operation/theory-advgnss https://www.vectornav.com/resources/inertial-navigation-prim...