2. Principle
All methods of 2D ultrasonic anemometers use a
transceiver and time-sharing method to measure wind
direction. If an ultrasonic anemometer uses a time-sharing
method, the sampling rate will be lower and the inner
structure will be more complicated. To alleviate the
problems of the time-sharing method, this study suggests
the system composition that is shown in Fig. 1. All
receivers can receive ultrasonic signals simultaneously by a
single transmission as shown in Fig. 1. In this structure, a
time control signal is not required in the transmitting
circuit, so the entire structure is simpler than the previous
ones.
Fig. 1. Schematic of ultrasonic anemometer using the directivity angle of
an ultrasonic sensor. Here, L is the length of the ultrasonic path, y is an
angle between the ultrasonic path and the bottom plate and j is the
directivity angle of the transmitter.