ultrasound;  wavelet transform;  threshold detection;  Ranging

By analyzing the shortcomings of ultrasonic ranging by the traditional threshold detection method, an underwater ultrasonic ranging method based on wavelet transform is proposed. Using digital signal processing technology, a digital band-pass filter based on Hamming’s window function is designed to digitally filter the sampled signal and construct a Gaussian wavelet base. An ultrasonic underwater ranging system that convolves the sampled signal with the wavelet base for wavelet transformation and accurately captures the arrival time of the echo signal is introduced. The traditional threshold detection method and the ultrasonic ranging method based on wavelet transform were used in the laboratory pool, and the measurement data were compared, which verified that the underwater ultrasonic ranging based on wavelet transform could achieve higher measurement accuracy and was better than the traditional threshold detection method.