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 (50) 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 (52) to extract phase and amplitude outputs (54 and 56), the phase output being unwrapped (70). The N and S phase signals and the E and W phase signals are then separately differenced (74 and 80) and the results used to compute (86 and 92) wind speed and bearing. Extracted amplitude signals (56) are put through a second wavelet filter (58) to remove echo clutter before being stored, along with the wind speed and bearing data in a range gate (96).
An ultrasonic flow sensor is used in particular for measuring the volumetric or mass flow of a fluid in a pipe. The sensor includes at least one ultrasonic transducer which is capable of emitting and receiving ultrasonic signals. An ultrasonic flow sensor, having in particular a simple and cost-effective construction and which functions according to the principle of beam drift, includes an array of a plurality of ultrasonic transducers which is positioned on one side of the pipe, a reflective surface lying opposite the array on which the emitted ultrasonic signals are reflected, and a receiver electronic system which evaluates the ultrasonic signal received from the ultrasonic transducers.
