LCJ Capteurs - Ultrasonic Wind Speed and Angle Indicators
These devices transmit ultrasonic (very high frequency) sound waves between paired electroaccoustic transducers. Wind blowing across these sensors interferes with the transmitted signals very slightly; enough to register transit time differences induced by the wind.
The temperature is also measured.
These tiny time differences are calculated, adjusted for temperature, and the resultant wind strength and vector are output in relation to a reference axis.
The effects caused by an inclination of the unit are partially compensated for by the shape of the unit and the space beneath it.
With no moving parts to clean and replace, this is a very low-maintenance instrument that provides exceptional accuracy (+/- 0.25kts) in up to 80 knot winds.