Field · GNSS

RTK GNSS centimetre accuracy: what it really takes in the field

13 min read June 8, 2026

Seeing a point on a phone is easy; trusting that point for engineering work is another matter. Phone location is often fine for reconnaissance. Cadastre checks, road axes, construction stake-out, earthwork limits and precision-agriculture lines need receiver quality, corrections, antenna setup, sky view and field control.

Field takeaways

RTK combines carrier-phase observation with reference corrections and can reach cm-level horizontal accuracy under the right conditions.
A fixed status is not a magic stamp. Known-point checks, repeat observations and tolerances still matter.
NTRIP/CORS needs internet for live corrections; recording and export can continue offline in MapLab Survey.
Multipath, wrong antenna height, pole tilt and high PDOP are common field error sources.
A wrong coordinate system can make a precise field point appear metres away in the office.

What RTK means on site

RTK is not just "GPS that gives centimetres". It is a measurement chain. A reference station or CORS network observes the same satellites, computes corrections and sends them to your rover. With clean signal, good geometry and a stable setup, the rover can solve the carrier-phase ambiguity and approach cm-level horizontal accuracy.

That chain includes the receiver, antenna, correction stream, connection, observation time, coordinate system and field control. MapLab Survey helps with capture, transformation, notes and export; the physical accuracy still depends on the receiver and the site.

NTRIP, CORS and TUSAGA-Aktif

In Türkiye, many RTK workflows use TUSAGA-Aktif instead of a local base. The receiver connects through NTRIP, receives RTCM corrections and improves the rover position. It is fast, but it needs mobile data, the right mount point and a reliable account.

If the connection drops, do not record critical points as if nothing happened. Mark the issue, repeat the point or check again once corrections are stable.

Fixed, float and known-point checks

A fixed status is good, but it is not a signature. Start on a known point, check again before critical work and close the day with another check. If the known point does not fit, stop and inspect the coordinate system, antenna height, mount point and receiver settings.

Common sources of error

Multipath: reflected signals near buildings, vehicles, fences or water.
Antenna height: a wrong pole height becomes a direct vertical error.
PDOP: poor satellite geometry weakens the solution even when the receiver reports a position.
Coordinate system: the wrong datum or zone can make a precise point appear far away in CAD/GIS.

A practical MapLab Survey workflow

Select the project coordinate system before measuring, record control points separately, attach notes/photos and export with the same project context. DXF, KML/KMZ, GeoJSON and CSV are useful only when the coordinate story is clear.

In the field · MapLab Survey

Measure, check and deliver in the right format.

MapLab Survey is a mobile field app for RTK/GNSS points, drawings, area/volume calculations, coordinate conversion and export to DXF, KML/KMZ, GeoJSON and CSV. Capture, calculation and export can work offline; live NTRIP corrections and online basemaps need connectivity.

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Frequently asked questions

Does RTK always give centimetre accuracy?

No. It depends on receiver quality, corrections, fixed status, antenna height, sky view and control checks.

Can RTK work without a CORS network?

Yes. A local base or PPK workflow can be used. CORS/NTRIP is a common live-correction workflow.

Can phone GPS replace RTK?

No. Phone location is useful for reconnaissance; survey work needs an external receiver and field control.

Does MapLab Survey create the accuracy?

MapLab Survey records, transforms, calculates and exports. Positional accuracy comes from the receiver, corrections and site conditions.

Technical references

The field guidance in this article is aligned with the technical and official references below.