The present invention is directed to a radio-acoustic sounding system for
providing wind measurements at altitudes of 100 meters or less. Wind
measurements are obtained by transmitting a pulse of audio frequency
energy through one or more volumes corresponding to the coverage area of
one or more radio frequency transceivers. The frequency of the audio pulse
is selected to have a wavelength that is one-half the wavelength of the
electromagnetic energy transmitted by the antenna or antennas. By
monitoring a return radio frequency signal at selected times following the
transmission of the audio pulse, wind data is obtained at selected
altitudes. Wind speed and direction can be obtained by observing the
Doppler frequency shift of return radio frequency signals, or by observing
the amplitude of the return radio frequency signals. In accordance with an
embodiment of the present invention, precipitation measurements may be
made by transmitting a radio frequency signal at the same radio frequency
as is used in connection with wind measurements, and observing return
radio frequency signals.
