Research On Vector Sound Field Characteristics And Features Of Targets In Waveguide Environment

With the human progress and science and technology development, the field ofoceanographic has become a hotspot research area and received more attention of more andmore scientific workers. It is essential and necessary to study the underwater soundpropagation because the sound waves are the primary carriers of information disseminationin the oceans.Unlike in the free field, the sound waves radiated by the acoustic source in thewaveguide environment will influenced by the surface and different kinds of acoustic sourcewith different influences. At the real ocean circumstance, both the waveguide environmentand the background noise will influence the propagation characteristic of underwater soundwave. According to the different position of the acoustic source, the background noisemainly classified into volume noise field and surface-generated noise field, it is essential tostudy the influences of the two kinds of noise field in the signal detection and processing.Based on the sound field characteristic of waveguide environment and the interference ofbackground noises, this paper discuss the application of many kinds of feature extractionmethod in the waveguide environment, compare with the feature extraction results in thefree field under the same acoustic source condition and study the effects of waveguideenvironment on feature extraction. The major works of this paper concrete from thefollowing several aspects:Firstly, use the image source method to model and simulate the radiated acoustic field inthe waveguide environment and compare with the free field condition with different acousticsources, then analysis the influences of the waveguide environment on sound fielddistribution with different sound resources.Secondly, classify and separately model the oceanic background noise according to thedifferent depth, analysis the influences of the background noise on signal receiving andprocessing by study the correlation coefficients of sound pressure and particle velocity involume and surface-generated noise fields model.Finally, employ many kinds of feature extraction methods include time domain,frequency domain and time-frequency domain in the free field and waveguide environmentseparately. Analysis the influences of the waveguide environment on the feature extractionby simulation and results comparing and discuss the effects of waveguide environment ondifferent methods by crosswise contrast. Study the target identification capability of every method discussed above by processing of the actual measurement data in real sound fieldwith background noise.