Sodar sounding of the lower atmosphere

Abstract

A method and system for acoustically sounding the lower atmosphere involves the transmitting of an acoustic chirp and the processing of returned echoes and interference using wavelet and matched filter techniques. A single transmitter and four receivers may be used, with receivers located equidistant from the transmitter on the cardinal points of the compass. N, S, E, & W inputs are digitized and input to a wavelet filter () together with the transmitter chip signal (R or D) for the attenuation of the direct signal and ambient noise signals. The interference-attenuated signals are then processed in a matched filter () to extract phase and amplitude outputs (and), the phase output being unwrapped (). The N and S phase signals and the E and W phase signals are then separately differenced (and) and the results used to compute (and) wind speed and bearing. Extracted amplitude signals () are put through a second wavelet filter () to remove echo clutter before being stored, along with the wind speed and bearing data in a range gate ().