Underwater Ultrasonic Multipath Diffraction Model for Short Range Communication and Sensing Applications

Abstract

In acoustic underwater communication and sonar applications, obstacles inside and outside the line-of-sight (LOS) affect signal propagation. Both reflection and diffraction occur in underwater communication and measurement systems due to these obstacles. To the best of our knowledge, the influence of diffraction and reflection is neither described nor modeled for finite pulses yet. We propose and develop a multipath propagation model for spectral diffraction components and phase information of the received signal based on knife-edge diffraction together with reflections, transmission effects, and backscatter. This paper designs a short range underwater ultrasonic experimental system composed of an ultrasonic transceiver with wideband pulses and advanced spectral signal processing. We evaluate our proposed model with measurements made in a water tank with an obstacle moved between the transmitter and receiver. When the model includes all major propagation components and effects, it achieves an accuracy for localization of 97 % of the results in the range of twice the obstacle diameter in our test setup.

Analysis of target recognition technology for autonomous underwater robot

“…Based on the elliptical coordinate system compensation method, this method increases the emission frequency of the transmitted signal and reduces the measurement error. Fabian John [24] proposes an underwater multipath ultrasonic propagation model that can achieve 97% positioning accuracy in the range of twice the diameter of obstacles, which is suitable for short-range communication and complex multipath propagation scenarios. Tang Bo [25] Aiming at the micro-Doppler effect generated by the echo signal of underwater targets, a vibration interference suppression algorithm is established to effectively suppress the interference of the micro-Doppler characteristic spectrum generated by underwater targets.…”

Time-frequency diffraction acoustic modeling of the Epidaurus ancient theatre

“…Diffraction phenomena have been studied in many diverse fields of acoustics, e.g. in underwater acoustics [1][2][3], aeroacoustics [4,5], building acoustics [6][7][8][9][10][11][12][13] and electroacoustics [14][15][16][17][18]. Especially for the study of sound propagation around finite surfaces and boundaries such as in room acoustics, it is increasingly evident that the sound field is properly described by both reflected and edge-diffracted components which can only partially be computed by the established geometrical acoustic methods.…”