Research On Underwater Fixed Frequency Signal Detection Based On EMI And ANN Technology

With the development of marine technology and marine industry,the demand for exploring underwater signal is becoming more and more urgent.Whether it is to detect the crash of the black box after the crash,or to find other fixed frequency signal components in the water.It is of great significance to protect the personal safety and social property to realize the rapid detection and location.In this paper,the detection and location of underwater fixed frequency signal(aircraft black box or submarine)as the background,based on the piezoelectric impedance technique,an experimental device and a theoretical method for underwater fixed frequency signal components are designed,an experimental platform for the simulation of ultrasonic beacon detection was builtand the experiment was carried out under water.Finally,combined with the BP neural network technology and the three ball positioning principle,the fixed frequency of the target is located.The main contents of this paper are summarized as follows:1)The current status of the research on underwater frequency signal detection and recognition at home and abroad is reviewed,the present situation of application and research of piezoelectric materials and EMI technology and the future direction of development were introduced,the application of ANN technology in scientific research was introduced,the theory of piezoelectric coupling impedance was described,and the relationship between the mechanical impedance and the piezoelectric impedance was analyzed.2)Finite element analysis of PZT by using ANSYS APDL piezoelectric analysis module was done,the deformation and the main deformation direction were analyzed,thefree modal analysis of the hemispherical piezoelectric impedance receiver was carried out to determine the natural frequency to avoid the target signal frequency,the reliability of experimental data was improved.3)A fixed frequency signal detecting device based on piezoelectric impedance technology was designed,an experimental platform for simulating the detection of fixed frequency signal was built,using the principle of the same frequency resonance of the target signal frequency and the sweep frequency,the two groups of different solid frequency signals were detected at different locations and depths.4)The basic theory of neural network localization and three ball localization was introduced,a BP neural network is established to locate the target signal,the target signal position is studied by using the trained network combining the principle of three sphere positioning,the feasibility of using the neural network technique to detect and locate the target solid frequency signal was discussed.