Real-time kinematic positioning compares carrier-phase measurements at a known base station and at the moving rover, linked by radio or internet, to resolve whole-cycle ambiguities and fix positions to a few centimetres. Because it gives accurate heights as well as positions, RTK makes ellipsoid-referenced surveys possible in real time. Accuracy degrades with distance from a single base, typically beyond 10 to 20 km.
RTK's fixed at 2 centimetres vertical, we're good to start running lines.
RTK heights are only as good as the base station coordinates; a base set up on the wrong mark shifts the whole survey without any internal sign of trouble.
Also heard as
- real-time kinematic
- RTK GNSS
Related terms
GNSS
Global navigation satellite systems: satellite positioning such as GPS, GLONASS, Galileo and BeiDou, used together.
Float
Describes an RTK solution whose carrier-phase ambiguities are not yet fixed, giving only decimetre-level accuracy.
PPK
Post-processed kinematic: GNSS positions computed after the survey from logged rover and base data, at centimetre level.
ERS
Ellipsoidally referenced survey: depths taken from GNSS ellipsoid heights and converted to chart datum with a separation model.