Research On Ocean Internal Wave Earlywarning And Monitoring Technology Based Onacoustic Vector Field Processing

As a frequent natural phenomenon,ocean internal waves have serious destructive effects on maritime military activities and Marine engineering construction.With the rapid development of ocean engineering and ocean economy,ocean internal wave monitoring and prediction technology has become a research hotspot at home and abroad.The traditional internal wave monitoring methods are mainly anchor array monitoring and satellite remote sensing observation.The anchor array monitoring method is based on the thermo-salt deep chain and ADCP sensors,which can monitor the physical changes of the ocean water to realize the ocean internal wave monitoring.The satellite remote sensing observation method is based on the satellite image analysis,through the image feature extraction and observation of the sea surface ripple caused by the internal wave to realize the ocean internal wave monitoring.The principles of the above two internal wave monitoring methods are clear,but they both have some obvious deficiencies.Moored array monitoring methods of anchor cable in the large size,complicated structure,cloth application cost is higher,the ADCP monitoring is easily influenced by current drag shaking and strong doppler effect,and the sea water by direct observation of physical change wave monitoring method in general it is difficult to realize unattended wave forecast within full autonomy.The problem of satellite remote sensing observation method is that it can only observe the specific internal waves that can affect the sea surface,but cannot directly and continuously observe the internal waves hidden in the sea bottom,and the accuracy of observation is greatly affected by the sea conditions.Therefore,there is no widely used autonomous prediction technology and equipment for ocean internal waves at present.In order to solve the above problems,this paper studies an early warning and monitoring method of ocean internal waves based on acoustic vector field processing.This method mainly uses the sea cloth vector hydrophone dives,using vector hydrophone ocean sound field three-dimensional vector information,based on sound pressure and velocity combined processing technology,in the first place in the complex ocean zhongtong too much background noise field search target azimuth scanning acoustic field of the main shaft as a source of acoustic target tracking monitoring,then the acoustic target source is space-time-frequency three-dimensional tracking,based on the acoustic target direction of the source of the vertical dimension feature is extracted,tracking,and jump to wave in the ocean monitoring and forecasting.The core of this method is based on the consensus in the field that internal waves can lead to drastic changes in the sound velocity profile of the ocean sound field,and the physical basis is not complicated.However,the drastic change of sound velocity profile will inevitably lead to the jump in the vertical dimension of the principal axis of ocean background noise.Therefore,the internal wave monitoring technology based on the jump characteristics can realize the full autonomous prediction of ocean internal waves.The submersible beacon of the vector hydrophone used in this paper has the advantages of light structure,low cost of installation and operation,and is theoretically not affected by sea conditions.The main work of this paper is as follows:(1)An early warning and monitoring method of ocean internal waves based on sound vector field processing is studied,including the search and tracking method of underwater non-cooperative target sound source under the condition of strong ocean background noise,three-dimensional tracking of non-cooperative target sound source based on sound energy flow and the detection and recognition method of ocean channel jump characteristics caused by internal waves,etc.(2)The internal wave monitoring method based on vector field processing proposed in this paper is simulated by computer,and the performance of the algorithm is verified.(3)Based on Lab VIEW development platform and ultra-low frequency vector hydrophone,the internal wave monitoring experimental prototype system is integrated,and the preliminary performance test of the prototype system is carried out,and the test shows that the system has good performance.