The comparative evaluation of the ray and wave components contribution to the impulse signals propagation of the Black Sea underwater sound channel

Abstract

The article is devoted to the simulation of signal propagation under conditions of the Black Sea underwater sound channel and comparative analysis of the ray and wave components contribution to a signal replica. To simulate the response to a signal, a method based on the convolution of a signal with an impulse response of a waveguide is used. The calculation of an impulse field in the form of convolution with an impulse response has several advantages: no Fourier transform of the signal is required; the convolution is performed in the time domain; the convolution is cyclic, what allows to simulate responses to continuous signals with a rapidly changing spectrum.
The impulse response of the waveguide is restored on the basis of the real recording of the explosive signal. To restore the impulse response, the underwater explosion signal is processed in several stages. The first stage is the processing in the spectral region: "bleaching" the spectrum of the explosion signal from the low-frequency component of a gas bubble pulses. The second stage is the processing of the bleached signal in the time domain: 1) manual filtration of a gas bubble pulses, where they can be separated; 2) noise reduction with variable threshold. Then, to study the dispersion law of the underwater sound channel and to identify ray and wave components of the signal, the responses to the test signals are analyzed. It is shown that for an adequate recovery of the waveguide response only the beam or only the wave approach is not enough. It is concluded that the impulse response of the waveguide is an effective tool for the simulation of a signal propagation. The advantage of a real impulse response is that it naturally includes both ray and wave components.