RTK Status & Accuracy

RTK positioning accuracy depends on the quality of the satellite fix and the correction data being received. This page explains the three fix quality levels, what affects accuracy, typical values you can expect on a construction site, and when RTK is sufficient versus when you need more precise methods.

Fix Quality Levels

The RTK receiver reports a fix quality value in every GGA sentence. SiteView interprets this into three levels, each with a distinct colour code in the status chip:

Single (Red)

Attribute	Value
Accuracy	Approximately 2-5 metres horizontal
Status chip colour	Red
Corrections	None — autonomous satellite navigation only
Suitable for	General navigation, finding approximate locations

A Single fix means the receiver is computing its position from satellite signals alone, without any correction data. This is the default state when no NTRIP connection is active or when the connection has been lost.

Float (Amber)

Attribute	Value
Accuracy	Approximately 0.2-1 metre horizontal
Status chip colour	Amber
Corrections	Receiving RTCM corrections, solution converging
Suitable for	Approximate setout, rough position checks, non-critical measurements

A Float fix means the receiver is receiving correction data and has partially resolved the carrier phase ambiguities. Accuracy is improving but has not yet reached centimetre level. Float solutions typically converge to Fixed within a few minutes if conditions are favourable.

Fixed (Green)

Attribute	Value
Accuracy	Approximately 10-20 millimetres horizontal, 20-40 millimetres vertical
Status chip colour	Green
Corrections	Receiving RTCM corrections, full integer ambiguity resolution
Suitable for	Survey-grade point capture, as-built measurements, construction setout, grade checking

A Fixed RTK fix means the receiver has fully resolved the carrier phase ambiguities. This is the highest accuracy level and is suitable for construction surveying work.

ℹ️ Did you know?

The accuracy values above are typical. Actual accuracy at any given moment depends on the factors listed in the next section. The receiver's reported accuracy estimate (shown in the status chip detail panel) gives you the real-time precision for the current conditions.

What Affects Accuracy

Several factors influence the accuracy of your RTK position:

Baseline Distance

The distance between your receiver and the nearest base station (or the virtual reference station position). Shorter baselines give better accuracy.

Baseline	Expected Accuracy
Less than 10 km	10-15mm horizontal
10-30 km	15-25mm horizontal
30-50 km	25-40mm horizontal
More than 50 km	Accuracy degrades, Fixed solution may not be achievable

Satellite Count

More satellites contribute to a stronger geometry and a more reliable position solution. A minimum of five satellites is needed for an RTK fix, but eight or more is preferable.

💡 Tip

Check the satellite count in the RTK status chip detail panel. If the count drops below six, consider waiting for satellite geometry to improve before capturing critical points.

Multipath

Multipath occurs when satellite signals bounce off buildings, vehicles, containers, or other reflective surfaces before reaching the receiver. This introduces errors that the receiver cannot fully correct.

To minimise multipath:

Keep the receiver away from large metal structures and building facades
Position the receiver in open areas where possible
Use a ground plane if your receiver supports one

Sky Obstructions

Trees, buildings, terrain, and overhead structures block satellite signals and reduce the number of satellites available. An open sky view is essential for reliable RTK performance.

Correction Data Age

As RTCM corrections age (the time since the last correction message was received), accuracy degrades. SiteView shows the age of corrections in the status chip detail panel. An age under 10 seconds is ideal; over 30 seconds may cause the solution to drop from Fixed to Float.

Colour Coding in the Status Chip

The status chip in the SiteView header uses traffic-light colours for instant recognition:

Colour	Fix Quality	Action
Red	Single	Do not capture survey points — connect NTRIP corrections
Amber	Float	Wait for convergence to Fixed before capturing critical points
Green	Fixed	Safe to capture survey-grade points

The chip also shows a numeric accuracy value (e.g., "0.014m") when hovering or clicking, giving you the exact precision estimate.

Typical Accuracy for Construction

For most construction surveying tasks, the following accuracy expectations apply:

Task	Required Accuracy	RTK Sufficient?
Bulk earthworks setout	plus or minus 50mm	Yes (Fixed RTK)
Subgrade and formation	plus or minus 30mm	Yes (Fixed RTK)
Kerb and gutter setout	plus or minus 20mm	Yes (Fixed RTK in good conditions)
Building setout	plus or minus 10mm	Marginal — depends on conditions
Structural steel / precise setout	plus or minus 5mm or tighter	No — use a total station
Deformation monitoring	Sub-millimetre	No — use specialised monitoring instruments

⚠️ Watch out!

RTK accuracy is probabilistic, not guaranteed. The stated accuracy values represent typical performance under good conditions (open sky, short baseline, stable corrections). Always check the reported accuracy before relying on a captured point for critical work.

When RTK Is Not Enough

For tasks requiring accuracy tighter than plus or minus 10mm, or where line-of-sight to the sky is limited, consider:

Total station — mechanical precision of plus or minus 1-3mm, works under cover and in obstructed environments
Level and staff — for precise height transfer over short distances
Control survey — for establishing a high-accuracy reference network

RTK is a powerful tool for the majority of construction measurement tasks, but it does not replace all survey instruments.

What's Next?

Capturing Points — capture survey points using your RTK fix
NTRIP Corrections — ensure corrections are configured for best accuracy
Connecting a Receiver — review the connection process
Grade Check vs Design — compare RTK-captured points against a design surface