Accuracy you can specify with confidence

Full-range accuracy describes measurement performance across a product's operating wind-speed range rather than at a single reference wind speed. Gill publishes this data for six products: WindSonic 60, WindSonic 75, WindObserver 65, WindObserver 70, MaxiMet and WindUltra. The figures are published in the datasheet and manual for each product.

Yes. It is normal for accuracy to change with wind speed. Higher speeds increase turbulence around the anemometer structure, which can naturally lead to a more variable response and so reduce accuracy.

How much it changes varies by sensor. The WindObserver 65 and WindObserver 70 hold the same stated accuracy across their whole measurement range. The WindSonic 60 and WindSonic 75 are stated in bands, with the figure widening at higher wind speeds. Having the full-range information available is what lets you pick the right product for the application.

The root mean square error (RMSE) is an averaged parameter which shows how far a device typically reads from an expected value. It incorporates both the bias error and variance of the instrument over a range of conditions.

We calculate RMSE from a full 360° rotation of the anemometer at each wind speed. This means that the errors calculated are a fair reflection of how the device might perform through all angles of attack.

The 2026 test programme covered the WindSonic 60, WindSonic 75, WindObserver 65 and WindObserver 70. It was carried out at accredited facilities at the University of Southampton, using a statistically significant sample of each product type, so the resulting accuracy figure reflects the product rather than the behaviour of a single instrument. RMSE is calculated from a full 360° rotation of the anemometer at each wind speed.

Six products: WindSonic 60, WindSonic 75, WindObserver 65, WindObserver 70, MaxiMet and WindUltra. All six are shown on this page with their published figures.

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Yes. The figures are published in the released datasheets and manuals for each product, which makes them citable in a tender response or design specification. They are derived from accredited testing across multiple units of each product type, so they can be justified if queried.

An anemometer accuracy specification describes how closely the sensor's reported wind speed and direction correspond to the actual conditions being measured. The way accuracy is stated matters because a single value at one reference wind speed does not describe performance across the sensor's complete operating range.

12 m/s is commonly used as a reference condition because it provides a consistent point at which different sensors can be assessed. It also sits above the average wind speed for the UK and Europe and is typical of a moderately strong breeze, so it long described the conditions most instruments encountered. It does not show how measurement performance behaves at other wind speeds, which is why full-range data matters for applications with a wider operating envelope.

Start with the wind speeds the sensor needs to measure, including the lowest and highest credible conditions. Then consider the required accuracy across that range, resolution and starting threshold, environmental conditions, output and communications requirements, power consumption and any approvals or certifications required by the application.

No. A wider measurement range is only valuable if the application needs it. The sensor should be selected according to the credible operating conditions, required measurement performance, environmental requirements and system specification. Specifying capability that the application does not need can add cost without providing a corresponding benefit.

Wind-speed range defines the conditions within which the sensor is designed to measure wind. Accuracy describes how closely its measurement represents the actual wind speed. A sensor can have a very wide measurement range without necessarily providing the same accuracy across every point within that range, which is why both specifications need to be considered.

Applications such as air-quality monitoring, environmental measurement and some meteorological systems may spend significant periods operating at relatively low wind speeds. Resolution and starting threshold become important in these conditions because the sensor needs to detect and report small amounts of air movement reliably.

Yes. Temperature, icing, corrosion, water ingress, vibration and exposure to severe weather can all influence sensor selection. The required environmental protection and construction should therefore be considered alongside measurement performance rather than treated as a separate specification.

An ultrasonic anemometer measures wind using ultrasonic signals rather than rotating cups and vanes. This removes mechanical components from the wind measurement process, which can reduce mechanical wear and maintenance requirements while also allowing compact sensor designs.

Compare the accuracy specifications under equivalent conditions and, where available, examine performance across the wind-speed range rather than comparing isolated reference-point figures. Also consider resolution, starting threshold, environmental performance, output, sampling rate and any application-specific approvals.

The sensor should be positioned so that the measured airflow is representative of the conditions the application is intended to monitor and is not unduly affected by nearby structures or other sources of flow disturbance. The appropriate installation arrangement depends on the application and relevant measurement standards.

The published data is included in the current released datasheets and manuals for each applicable product. These documents are available from this page and from the individual product pages.

Because customers ask for it and tenders increasingly require it. Instruments are being deployed in more extreme conditions and across a wider geographic spread than when the 12 m/s reference point was set, and full-range accuracy statements are now common across the sector. Publishing the data gives engineers a more complete basis for specification and lets products be assessed against the conditions they will actually encounter.

That depends on the wind range, environment and purpose of the measurement. If accuracy is critical to the application, a Gill expert can help establish which sensor and performance specification are appropriate.