Airborne wind measurements

OPTOLUTION has developed the OPTOkopter wind measurement system for commercial use: Drones are available for purchase worldwide and for service measurements.

The OPTOkopter is the most advanced, commercially available drone-based wind measurement system: 

• We have extensively tested different available 3D ultrasonic sensors under a very large range of angles of attack and yaw angles in a wind tunnel. The sensors were compared to our LDV measurements and are corrected for shadowing effects at high angles of attack.
• We characterised the influence of the drone itself in many measurement flights, and during free flight in wind tunnels. All the influences are compensated for.
• Our wind measurement code effectively compensates for the influence of any motion and rotation of the drone using high frequency IMU data.
• We have confirmed the accuracy of our wind measurements for both hovering and translational flight using the bistatic lidar of the PTB, Germany's national metrology institute. This unique lidar has a measurement volume size comparable to that of the ultrasonic sensor used.
• We are collaborating in several research projects and continuously improving our measurement accuracy.
• Our research on drone based wind measurements is published in a highly cited research paper in AMT.

The OPTOkopter has been developed for airborne, three-dimensional wind measurements. A high-precision, 3D wind sensor is carried by a drone that was designed for this purpose. The drone was optimized for long flight times and precision flight. A RTK-GPS allows for centimeter-level accurate, automatic flights.

The OPTOkopter has been developed from scratch and is optimized for measuring 3D wind speed:

• Calibrated, high-precision 3D sonic anemometer
  
  • True three-dimensional flow velocities
  • Uncertainties: Wind speed ± 1 % ; wind direction ± 0.5 °
  • Sample rate: 20 Hz
• Optimal aerial platform
  
  • Perfectly stable, smooth and agile multirotor
  • Precise compensation of rotor-induced flows and platform motion
  • 45 minutes autonomy with sensor payload, quick battery swap
  • Weight: 4.9 kg, dimensions: 0.96 m ∙ 0.96 m ∙ 1.46 m
  • Wind speed up to 12 m/s (ca. 5 Bft)
  • Centimetre-level 3D positioning with RTK GPS
  • Automatic flight on 3D measurement grids

Precise airflow measurements are important to understand, predict and simulate flow phenomena. Determining flow velocities is essential for:

• Wind load and construction analysis
• Urban climate analysis and building aerodynamics
• Optimisation of wind farms and wind energy yield
• Micrometeorology and gas dispersal

Our publicaton in the AMT journal about the OPTOkopter

https://amt.copernicus.org/articles/14/1303/2021/