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Study Of DOA Estimation Approachfor The Extendible Sonar Array

Posted on:2018-12-14Degree:MasterType:Thesis
Country:ChinaCandidate:L LiFull Text:PDF
GTID:2322330542487504Subject:Engineering
Abstract/Summary:PDF Full Text Request
DOA estimation isan important component of the underwater detection and location,for military and civil.As the performance of high-frequency absorption improving,the sonar is designed in low-frequency in modern time.It is means that the sonar system should be designed with larger array aperture.However,the size of the sonar array is limited by many factors.The aperture extendible sonar array can be folded save the space in the spare time.It canbe developed in detection program to enlarge the array aperture.Therefore,it is widely used in many platforms in installation dimension limitation.In this thesis,a precise DOA estimation method is proposed for a aperture extendible sonar array with a 12 arm–24elementsin engineering application.Firstly,the classical DOA algorithms were studied,and the characters and applied ranges of every algorithm were analyzed.Then,modified algorithms were proposed,based on environment and array structure characters.Finally,the performance of the modified algorithms was analyzed,and verified in computer simulations,pool experiments and lake experiments.The simulation results shows that:the DC weighted approach can suppress the side lobe level;the higher sample rate of the array output can smooth the main lobe in directivity function;more pre-formed beam forming,can achieve higher precision of DOA estimation;the DOA estimation performance will be decreased with the narrowerbeam width,and the DOA estimation error was changed,periodically,in cycle of 30~o;the array posture compensation method was benefit for the DOA estimation.The pool experiments and lake experiments results show:the mean squared error of actual DOA estimation was 0.5~o,and the array posture compensation method can significantly correct the error,generated by the array posture changes which include the flow turbulence and array rotation.The engineering implement of precise DOA estimation for the aperture extendible sonar array was supported by the results of this thesis.However there ismuch work to make the proposed algorithms in engineering,such as the optimal real-time signal processing,different environment conditions.
Keywords/Search Tags:Extendible Sonar Array, Vertical Linear Array, Uniform Circular Array, DOAEstimation
PDF Full Text Request
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