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The Research For Array Shape Estimation Of Towed Linear Array Sonar

Posted on:2018-07-16Degree:MasterType:Thesis
Country:ChinaCandidate:Y WangFull Text:PDF
GTID:2322330542987502Subject:Engineering
Abstract/Summary:PDF Full Text Request
Array shape deformation plays a key role on the influence of towed linear array sonar.It is a realistic choice and basic technique approach to estimate the array shape real time to make the time-varying shape match the model used by signal processing.In this thesis,a novel method is proposed to model the towed cable,towed array and rope as a combined body,using both theoretically modeling and experiment for investigation to set up the array dynamic model in partial difference equations and coupled with sonar signal processing to solve the problem of array shape estimation,research work is as following:(1)In order to construct the dynamic equations of the total wet end,both the stress and strain relations have been investigated to keep the balance of stress,among which the stress inside the wet end,caused by wave and turbulence.As a result,both the partial equations and boundary conditions have been constructed,and pave the way for analysis the influence of environmental factors such as towed shipe,current,wave.(2)Once the theoretical models obtainded,it is necessary to find the way for solving the partial equations.Because of the inner complex nonlinearity,the numeric approach is used to sovle these equations.By dieviding the wet end into a group of small discrete parts and using difference instead of differential,these equations can be changed difference equations which can will be solved by computer and to gives solutions with in shorter time and better accuracy.(3)For the purpose of displaying the array shape deformation on sonar detection,the simulation environment embedded in both array shape prediction and sonar beamforming has been established.In this simulation environment,multi-target and arbitrary aperture array can be set to feed the input of sonar beamforming to demonstrate the effect before and after the array shape calibration.(4)Array shape calibration methods have been investigated using the measured simulated data obtained by hydrophones.The theoretical framework of joint estimation of target bearing and array shape has been constructed and the simulation results according to the specific geometry of towed linear array sonar have been proposed to evaluate efficacy.This research is very useful for improving the grade of maturity in shape estimation and calibration of towed linear array sonar,and can intensify the engineering application in the near future.As a result,the tactical performance of towed array sonar will be improved with this favor.
Keywords/Search Tags:Towed linear array sonar, Array shape deformation, Array calibration, Beamforming
PDF Full Text Request
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