With the recent discussions on a new Australian datum (GDA2020), I have come across several queries regarding datum implementation in CORS network system and RTK service.
The basic principle to keep in mind is that RTK, or more descriptively, carrier-phase double-differencing, is a relative positioning technique. Unlike DGPS or PPP, it does not solve directly for coordinate but instead compute the vector (baseline) between the reference point (base station or CORS) and the unknown point. This vector is then applied to the known, accurately surveyed coordinate of the reference point to produce the coordinate of the unknown point (see Hofmann-Wellenhof, Lichtenegger, Collins, GPS Theory & Practice, Section 8.3 for further details). Read More