akar.earthRTK GNSS: Definition
What is RTK GNSS? How real-time kinematic positioning gives centimetre-level accuracy for plot mapping, EUDR polygons and carbon project boundaries.
RTK GNSS (real-time kinematic global navigation satellite system) is a positioning technique that corrects satellite signals using a nearby base station or a correction network, giving positions accurate to a few centimetres instead of the several metres typical of a phone GPS.
Why it matters
Location error causes real problems in carbon and EUDR work. A plot placed 10 m off can match the wrong satellite pixels, distorting biomass models. A farm polygon drawn with a phone may overlap a neighbour or a forest boundary, triggering a false deforestation flag. RTK reduces these errors, which makes plot data more useful for calibration and boundary data more defensible to verifiers and buyers.
How it works
A base receiver at a known point, or a network service, computes the error in satellite signals and sends corrections in real time to a rover receiver in the field. The rover uses carrier-phase measurements to fix its position precisely. Many field teams now use compact RTK receivers paired with phones or tablets. Our RTK GNSS plot mapping guide covers setup and checks.
Indonesia and Southeast Asia angle
Correction networks are uneven across Indonesia, so remote sites in Kalimantan or Papua often need a local base station. Dense canopy and steep slopes reduce satellite visibility. Practical fixes include measuring plot centres in nearby gaps and offsetting, logging longer observations and recording fix quality. For smallholder coffee, cocoa and palm plots, RTK-surveyed boundaries help meet EUDR polygon requirements with confidence.
Survey quality should be recorded for every point, including fix type, number of satellites and estimated accuracy, so that later users know which coordinates can be trusted.
Common mistakes
- Accepting “float” rather than “fixed” solutions without noting the lower accuracy.
- Using a base station whose own position is unknown or wrong.
- Mixing coordinate systems or datums between datasets.
- Assuming RTK works equally well under closed canopy.
See also ground truth and our field data campaigns.
Frequently asked questions
How accurate is RTK GNSS?
Under open sky with a good correction signal, RTK typically achieves centimetre-level accuracy. Under dense forest canopy accuracy drops and fixes can be lost.
Do I need RTK for EUDR polygons?
EUDR does not require RTK. It requires coordinates with at least six decimal places. Better accuracy reduces disputes when plots are checked against satellite data.