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简介:Inordertoimprovetheperformanceoflinespectrumdetection,accordingtothefeaturethattheunderwatertargetradiatednoisecontainingstablelinespectrum,thedifferencesofthephasedifferencebetweenlinespectrumandbackgroundnoise,aweightedlinespectrumdetectionalgorithmbasedonthephasevarianceisproposedinfrequencydomain.Afterphasedifferencealignment,thephasevarianceoflinespectrumandthephaseofbackgroundnoise,respectively,aresmallandbiginfrequencydomain,thismethodutilizestheweightedstatisticalalgorithmtocumulatethefrequencyspectrumbasedonthephasevariance,whichcanrestrainthebackgroundnoisedisturbance,andenhancethesignaltonoiseratio(SNR).Thetheoryanalysisandexperimentalresultsbothverifythattheproposedmethodcanwellenhancetheenergyoflinespectrum,restraintheenergyofbackgroundnoise,andhavebetterdetectionperformanceunderlowerSNR.
简介:Thelowfrequencylinecomponentsoftheradiatednoisefromanunderwatertargetusuallyhavebothhighspectrumlevelandsustainedstability.Thisfeaturecouldbeusedtoincreasethedetectionperformanceofconventionalbroadbandenergyintegrationmethod.Therequiredspectrumlevelistheoreticallydiscussedwhenthedetectionperformanceoftheknownlinedetectionisbetterthanthatofbroadbandenergyintegrationmethod.Undertheconditionofthetargetcanbedetectedinlinespectrumband,therelationshipbetweenthelinespectrumlevelandsignaltonoiseratio(SNR)isalsodiscussed.ThispaperproposesalinespectrumtargetdetectionmethodthatamatrixusingDCjumptofluctuationsratiosofsub-bandspatialspectrumandbeamspaceoutputisconstructed.Thismatrixactsasafilterthatthelinespectrumtargetwithcertainfrequencyandazimuthispassedatmost.Byfusingwiththeothersubbandresults,theconventionaldetectionperformancecanbeimproved.Atthesametime,theapplicableconditionanddetectionperformanceareanalyzedinthepaper.Thesimulationandtheseatrialdataprocessingresultsshowthatthealgorithmcaneffectivelyextractweakgoallinespectrumtargetundertheconditionofmulti-interference.Thealgorithmdoesn’tneedmulti-framestatisticsandthedetectionperformanceisclosertotheoptimallinespectrummethod.
简介:摘要随着对以可再生资源为基础的电力生产的需求日益增加,使得有效地利用现有资源变得极为重要。潮汐和洋流都会周期性的移动大量的水,这些水携带着大量的动能,可以用来生产能源。但到目前为止,由于潮汐和洋流的速度相对较慢,现有技术很难直接利用潮汐和洋流发电。本设备依据相对运动的原理,利用机翼形运载体携带涡轮发电机在水流中运动发电。工作时设备主体的机翼利用自身浮力和水流作用在上面的升力使主体在水中漂浮,设备内部放置传感器测定缆线倾角、缆线拉力、机翼倾角以及水流流速等物理量,调节机翼倾角使设备在预先规划的形似“8”字形的路径上运动。该设计能有效的提高低流速的潮汐、洋流等的发电利用效率,改善原有利用潮汐、洋流发电的设备的发电功率不稳定的问题,更好地利用潮汐、洋流等这一新能源动力。
简介:水下多目标跟踪逻辑与决策是水下航行器多目标跟踪中需解决的技术难点.目前用于水下多目标跟踪决策的方法都假设各个决策因素相互独立,而实际上水下多目标跟踪决策的因素之间存在着相互影响.本文根据这一特点,建立了水下多目标跟踪决策的指标集和相应的ANP决策模型,提出了基于ANP的水下多目标跟踪逻辑与决策方法.该方法将水下多目标跟踪决策的指标集纳入网络层次结构模型,并通过模型解算得到优化的多目标跟踪决策,具有决策结果比现有方法更加合理、稳健的特点.仿真结果表明该方法是在多目标跟踪决策因素之间存在相互影响情况下解决水下多目标跟踪逻辑与决策问题的有效方法.
简介:Inunderwatertargetdetection,thebottomreverberationhassomeofthesamepropertiesasthetargetecho,whichhasagreatimpactontheperformance.Itisessentialtostudythedifferencebetweentargetechoandreverberation.Inthispaperbasedontheuniqueadvantageofhumanlisteningabilityonobjectsdistinction,theGammatonefilteristakenastheauditorymodel.Inaddition,time-frequencyperceptionfeaturesandauditoryspectrafeaturesareextractedforactivesonartargetechoandbottomreverberationseparation.Thefeaturesoftheexperimentaldatahavegoodconcentrationcharacteristicsinthesameclassandhavealargeamountofdifferencesbetweendifferentclasses,whichshowsthatthismethodcaneffectivelydistinguishbetweenthetargetechoandreverberation.
简介:Alookattheongoing'5pointsin1line'coastlinedevelopmentprojectinLiaoning,NortheastChinaLIAONINGProvinceinNortheastChinawasoncethecountry'sindustrialengine.WithinadecadeofNewChina'sfounding,itwaschurningouteverythingfromcoalandsteeltofighterjets.Buttheenginesplutteredoutinthemid-1990s,whenmanyofLiaoning'sstate-owned