rtk

Real-Time Kinematic (RTK) is a GNSS positioning technique that achieves centimeter-level accuracy by exploiting carrier-phase measurements and applying real-time differential corrections from a reference station to a rover. Corrections are used to resolve integer ambiguities in the carrier phase, enabling precise positioning as measurements are processed.

In a typical RTK setup, a base station at a known position observes GNSS signals from constellations such as GPS, GLONASS, Galileo, and BeiDou and computes corrections. These corrections are transmitted to a rover via radio, cellular, or internet links. The rover applies the corrections to obtain a real-time, high-precision position. Network RTK (NRTK) expands this by using a network of reference stations to generate correction data for the rover’s location, often delivered through the NTRIP protocol.

Accuracy and requirements: RTK commonly yields horizontal accuracy of about 1–3 centimeters and vertical accuracy of 2–5 centimeters under good conditions. Performance degrades with longer baselines, signal multipath, satellite geometry, or poor communication links. Initialization time can vary as the system resolves ambiguities and establishes a stable solution.

Applications and limitations: RTK is widely used in surveying, construction staking, precision agriculture, machine control for earthmoving equipment, mapping, and autonomous navigation systems. It requires reliable communication with a reference station or network, and performance can be degraded in urban canyons or under dense canopy. Alternatives include post-processed kinematic (PPK), which uses logged data after the fact, and precise point positioning (PPP), which relies on global corrections without a local base but may require longer convergence times.