Research On Underwater Acoustic Parameter Acquisition Technology Of Chirp Subbottom Profiler

Detection technology is a kind of shallow profile based on the principle of underwater acoustics is continuous navigation type detecting underwater shallow strata structure and tectonic geophysical methods,using sound waves in the sea and the propagation and reflection of the seabed sediment characteristics and regularity for continuous detection of the seabed sediment structure,in order to gain an intuitive seabed shallow strata structure section,the technology has been widely used in sea bottom sediment survey and research.The technique of shallow strata section detection has the characteristics of high resolution and high detection efficiency.Now,researchers are more in-depth and accurate in the study of the seafloor sediments,not only for the purpose of qualitative survey,but also for the quantitative study of the physical parameters of the sediments.Through forward modeling and inversion of high-resolution shallow section data,more accurate characteristics parameters of shallow strata are obtained.In this paper,data processing and acoustic parameter acquisition techniques for Chirp shallow profile sonar data are studied.Firstly,a shallow-profile signal processing technology based on fractional Fourier transform is proposed to obtain high-quality signal with enhanced signal-to-noise ratio in the transform domain.Compared with copy-dependent processing technology,a conclusion can be drawn that the use of fractional Fourier transform is more suitable for processing Chirp shallow-profile signal.Secondly,a shallow formation sound velocity estimation algorithm based on genetic algorithm is proposed.Based on the ray theory and combined with the multi-beam sonar detection characteristics,a sound velocity profile solution model is established and the sound velocity of each layer in the seabed layered medium is obtained.Finally,using the fractional Fourier transform processing after the Chirp of shallow profile control signal,with high signal-to-noise ratio of the seabed sediment profile,extract acoustic propagation delay between the layers and each layer of acoustic reflection intensity,time of relaxation method is used to get the bottom of the sea sedimentary layer upon layer between the acoustic attenuation coefficient,and in the case of estimated noise attenuation,through sound waves in the transmission and reflection of the relationship between layer and sediment acoustic impedance.