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What RTK accuracy depends on
What RTK accuracy depends on: distance to the base, sky view, multipath, antenna, ionosphere and age of corrections – and what to do for a stable FIX.
5 min read
| Factor | Impact | What to do |
|---|---|---|
| Distance from the base | About +1 mm per km (ppm) and slower FIX at longer distances | Use AUTO – always the nearest base station. |
| Sky visibility | Trees, buildings and power lines reduce the number of satellites | Four constellations help; avoid initialising under tree canopy. |
| Multipath (reflections) | False measurements from metal surfaces and walls | Mount the antenna high, away from the cab/silos. |
| Antenna quality | Cheap antennas = weaker FIX | Multi-frequency (L1/L2/L5) antenna with a ground plane. |
| Ionosphere | Solar activity occasionally makes FIX harder | Multi-frequency receivers are considerably more resilient. |
| Age of corrections | Above ~5 s accuracy degrades quickly | Stable mobile signal; external antenna for the modem. |
Repeatability vs absolute accuracy
Repeatability (pass-to-pass and year-to-year) is what matters most in agriculture: the same base station gives the same coordinates every year. Absolute accuracy in the national coordinate system also depends on the accuracy of the base station position and on the transformation – see coordinate systems.
Related: You can see the distance to the nearest base on the coverage map – best accuracy is within ~30 km. Specific symptoms and fixes are covered in troubleshooting.