What is RTK?

RTK (Real-Time Kinematics) is a technique used for high precision GPS/GNSS (Global Navigation Satellite Systems) to eliminate errors that prevent GNSS receivers from achieving a position accuracy down to millimeters. Regular standalone GNSS receivers in the market achieve position accuracies of 1 – 2 meters, which is not sufficient for applications that require better accuracy , e.g. in agriculture, robotics or automotive industries.
When applying correction data from a nearby reference receiver to a rover receiver, applications can reach precision levels of 1 cm or better.
The rover’s position accuracy and convergence time will depend on its distance to the reference station.
Such corrections are available from RTK correction services, based on geographically distributed CORS (Continuously Operating Reference Station) networks.
Detailed explanations for RTK are available e.g. from Wikipedia, Emlid, or everythingRF.com.

Applications of RTK

RTK receivers and RTK correction services have been extremely expensive for many years, which has limited adoption of RTK positioning in mass markets. Due to the increasing demand for higher accuracies in autonomous vehicles, advances in receiver technology together with the availability of new GNSS signals have brought RTK receiver prices down by more than one order of magnitude. The lower receiver prices have made RTK technology more attractive for mass market applications. However, correction service costs have not come down by the same extent, and hinder widespread adoption.