RTK and PPK: georeferencing without many ground points
How RTK and PPK determine the drone's position to the centimetre — and what the difference is.
RTK and PPK are techniques to determine the drone's position very accurately during the flight, so that every photo already has a precise location.
RTK (Real-Time Kinematic)
Corrects the position in real time via a base station or correction network. The drone already knows during the flight where it is, to within a few centimetres.
PPK (Post-Processed Kinematic)
Calculates the accurate positions after the flight by combining the drone data with that of a base station. Robust, as no live connection is needed.
What about ground points?
With RTK/PPK you need fewer GCPs, but a few control points remain useful to verify the absolute accuracy.