Research On Detection Technology Of Ship Based On Submarine Buoy Platform

Underwater buoy is a kind of working platform used for underwater monitoring,which can effectively monitor the target sea area for a long time.This paper mainly focuses on the acoustic detection requirements of the surface ships in a specific area,and carries out the research of acoustic signal detection and direction finding technology based on the submarine buoy platform.First of all,the modeling and computer simulation of ship radiated noise are studied.Based on the analysis of the composition and generation mechanism of ship radiated noise signal,the distribution characteristics of ship radiated noise in time,frequency and high-order domain are studied.The typical characteristics are extracted and the effectiveness of modeling and simulation is verified by real ship data.Low frequency line spectrum and modulation information are the most important characteristics of ship radiated noise.This paper analyzes and compares the line spectrum and modulation information of ship radiated noise by using LOFAR spectrum analysis,demon spectrum analysis,1.5D demon spectrum analysis and 2.5D demon spectrum analysis and other spectrum analysis technologies,which lays a theoretical foundation for the subsequent target detection.Secondly,combined with the time-domain waveform characteristics of low-frequency signal of ship radiated noise,the detection effects of traditional algorithms such as broadband energy detection method and zero crossing detection method under different signal-to-noise ratio and false alarm probability are studied.On this basis,in order to further improve the detection ability of ship targets,this paper studies the joint feature detection technology based on spectrum analysis,making full use of the frequency domain,high-order domain and modulation information of radiated noise,extracting ship radiated noise features from multiple perspectives,constructing joint feature space,matching and detecting the extracted radiated noise features using support vector machine technology The detection ability of joint feature detection technology is verified.Finally,aiming at the limited space of underwater buoy platform,the target direction finding technology under the condition of small platform is studied,and the influence of array spacing and time delay estimation error on the direction finding accuracy is analyzed focusing on the traditional plane five element cross array.Aiming at the problem that time delay estimation error has great influence on direction finding accuracy,a high-precision time delay estimation algorithm based on high-order cumulant is proposed.The time delay estimation accuracy of the algorithm under different noise environment and different signal-to-noise ratio is analyzed,and then the direction finding technology is simulated and compared.