Ultrasonic Wind Measurement Technology

Vaisala utrasonic wind measurement technology uses ultrasound to determine horizontal wind speed and direction. The measurement is based on a proprietary triangular measurement array. The array design ensures accurate wind measurement from all wind directions, without blind angles or corrupted readings.

The ultrasonic measures the transit time, the time it takes for the ultrasound to travel from one transducer to another, depending on the wind speed along the ultrasonic path. With wind along the sound path, the upwind transit time increases and the downwind transit time decreases. From transit times at three different measuring paths, the microcontroller computes the horizontal wind speed and direction.

Time-of-flight for a sonic impulse from the transmit transducer to the receive transducer is determined for both directions. Simple algebra allows solving for the parallel component of wind velocity independently of the static speed of sound.

The equilateral triangle configuration of the three transducers provides three possible sets of basis vectors. The combinations yield bi-directional measurements on the paths labeled A, B and C. These measurements are used to determine the wind velocity components parallel to each of the three paths.