The platform is part of every reading
Wind measurement on a moving platform starts with the platform: its speed, heading, motion and structure all end up in the reading. Gill ultrasonic sensors such as WindUltra are compact, light, sealed and heated for vessels, USVs, buoys, vehicles and UAVs.
How do you measure wind on a moving platform?
A wind sensor on a moving platform measures apparent wind: the true wind combined with the platform’s own speed, heading and motion. True wind is calculated by removing the platform’s speed and heading from the apparent wind vector. The result depends on three things: the wind sensor, the quality of the heading and speed data, and where the sensor is mounted.
The sensor also has to live with the platform. Pitch, roll and heave move it through the air, the structure bends the airflow around it, and on an autonomous vessel or drone every gram and every watt comes out of payload and endurance.
Motion, weight and water
A wind sensor that does well on a fixed mast can struggle on a moving platform. On a drone it costs payload. On a small USV or buoy it has to treat spray, wave wash and submersion as normal operation.
Even a well-chosen sensor reports only apparent wind until the platform supplies its heading and speed. Four constraints shape the choice: motion, weight, water and placement.
Apparent is not true
The sensor measures apparent wind. True wind needs the platform’s heading and speed.
Heading from a compass or the platform
Every gram counts
On a UAV or small USV, sensor weight is payload and endurance.
WindUltra: 270 g with 1 inch pole mount
Water is part of the job
Small vessels and buoys see spray, wave wash and submersion as normal operation.
WindUltra: IP66, IP68 and IP69k
The structure bends the air
Masts, rotors and hulls distort airflow. Placement decides how representative the reading is.
Choosing for a moving platform
Each option below is used on moving platforms. The correct one depends on size, power, approvals and what else needs measuring.
| Consideration |  WindUltra |  WindSonic M |  WindObserver |  MaxiMet Marine |
|---|---|---|---|---|
| Best suited to | UAVs, USVs, buoys, small platforms | Vehicles and vessels needing a heated, rugged sensor | Commercial and naval vessels with approval needs | Vessels and buoys needing weather as well as wind |
| Size and weight | Smallest and lightest, 270 g with mount | 0.9 kg, aluminium | 1.3 to 1.9 kg, stainless steel | Compact station, 0.5 to 0.7 kg |
| Protection | IP66, IP68, IP69k | IP66 | IP66 | IP66 and IP68 |
| Heading | From the platform | From the platform | From the platform | 6-axis compass built in |
| Wind range | 0 to 75 m/s | 0 to 60 m/s | Up to 90 m/s | 0 to 60 m/s |
For autonomous and small platforms, WindUltra is usually the starting point. For vessels that need class approval, WindObserver is. For wind plus weather with its own heading, MaxiMet Marine.
Small has trade-offs
Small means 2-axis
WindUltra is 2-axis. Vertical wind and turbulence need a 3-axis sensor, which is larger.
Heating costs power
WindUltra has integral heating. On a battery platform the heater needs its place in the power budget.
Digital outputs only
WindUltra’s order codes list digital outputs. A platform expecting analogue needs a different sensor or an interface.
Placement is a compromise
The best airflow is often at the top of a mast or ahead of rotors, which is also the most exposed and least stable position.
Small, sealed and heated
Every option is ultrasonic, so there are no rotating parts to be damaged by shock or submersion.
WindUltra
Compact, lightweight, extremely tough
Tested against wind-blown dust and sand, pressurised water, impact, shock, vibration and altitude.
WindSonic M
Heated aluminium 2-axis anemometer
Hard-anodised aluminium and heating for vehicles and vessels in cold and harsh conditions.
MaxiMet Marine
Wind and weather with a compass
GMX260 and GMX560 add a 6-axis compass and IP68 for vessels and buoys.
insight
True wind is a calculation
No sensor on a moving platform can measure true wind directly. It measures the air moving past it, which is apparent wind.
True wind is calculated by subtracting the platform’s own velocity, its speed and heading, from the apparent wind vector. The quality of the result depends as much on the heading and speed data as on the wind sensor.
On a vessel, heading and speed usually come from the ship’s gyro and GPS. On a buoy or small USV, a sensor with its own compass, such as MaxiMet Marine, can provide heading. On a UAV, the autopilot’s own navigation solution does the job.
Platform motion adds a further layer. Pitch and roll move the sensor through the air, so fast platforms and rough conditions benefit from averaging and from mounting the sensor where motion is smallest.
The full explanation is in What is the difference between true wind and apparent wind?
Wind measured on the move
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Speak to our team
Tell us what you need to measure, where and under what conditions. We’ll help you work out the appropriate approach.
Moving platform questions
Apparent wind is the wind measured on a moving platform, combining the true wind with the platform’s own motion. A sensor on a vessel, vehicle or UAV always measures apparent wind.
True wind is calculated by removing the platform’s own velocity, its speed over ground and heading, from the measured apparent wind vector. The accuracy of true wind depends on the heading and speed data as well as the wind sensor.
A drone wind sensor needs to be small, light and low power. Gill WindUltra is the smallest and lightest Gill anemometer, 270 g with a 1 inch pole mount, with no moving parts and IP66, IP68 and IP69k protection. Placement relative to the rotors strongly affects the reading.
Gill WindUltra is rated IP66, IP68 and IP69K, which suits USVs and buoys that see wave wash. Other Gill anemometers are rated IP66.
A heading source is needed to calculate true wind or to reference wind direction to north. It can come from the platform’s own navigation system or from a sensor with its own compass, such as the marine MaxiMet GMX260 and GMX560, which carry a 6-axis compass.
Turbulence needs a 3-axis anemometer, such as Gill WindMaster, and careful correction for platform motion. Saildrone USVs have used Gill WindMaster 3-axis anemometers for wind measurement at sea.