简介:摘要:随着超高压以及特高压的飞速发展,大电网互联成为必然的发展方向。在带来巨大经济效益的同时,互联大电网之间的低频振荡问题也越来越严重,这对互联大电网的安全与稳定带来了巨大隐患。快速对低频振荡进行模态辨识对保证供电可靠性具有重大意义。低频振荡信号的模态方法有两种,与耗时时间长和维度大的特征根的辨识方法相比,基于实测信号辨识方法具有天然的优势。基于实测信号的辨识方法主要有FFT方法、MP方法、Prony方法、HHT方法、TLS-ESPRIT方法方法等。然而这些方法大都只考虑了高斯白噪声,对高斯色噪声的考虑不足。
简介:次同步振荡采集信号中含有的高斯白噪声,经过滤波处理后会转变为高斯色噪声。针对传统辨识方法在同时存在色噪声和白噪声环境中辨识精度不高的问题,本文从减少噪声的角度提出以实测信号的四阶混合平均累计量(FOMMC)的对角切片来代替实测信号,并结合总体最小二乘一旋转不变技术参数估计(TLS—ESPRIT)算法进行次同步振荡模态在线辨识。仿真结果表明,FOMMC—TLS—ESPRIT能够从强噪声环境中有效辨识次同步振荡模态,为次同步振荡的抑制奠定基础。
简介:ESPRIT测向算法需要预先知道来波的数目.本文对ESPRIT算法进行了改进.改进后的算法把对空间来波数目的估计和空间来波方向的估计有效地结合起来,从整体上减少了运算量,而没有降低测向性能.最后进行了计算机仿真.仿真结果表明,该算法切实可行,具有工程应用价值.
简介:提出了一种新的单基地MIMO雷达波达方向(DOA)估计算法:降维Power-ESPRIT算法。该算法首先通过降维变换将MIMO雷达数据变换至低维信号空间,然后进行从复数域到实数域的转换,并在实数域上使用采样数据协方差矩阵的幂获得信号子空间的估计,最后构造实值旋转不变性方程估计目标的DOA。仿真结果表明,在低信噪比、低快拍数的环境下,该算法与已有ESPRIT方法相比,具有近似性能,却拥有较低的计算复杂度。该算法的计算复杂度是RD-ESPRIT的25%左右,是RD-UESPRIT的65%左右。
简介:Inthispaper,alowcomplexityESPRITalgorithmbasedonpowermethodandOrthogo-nal-triangular(QR)decompositionispresentedfordirectionfinding,whichdoesnotrequireaprioriknowledgeofsourcenumberandthepredeterminedthreshold(separatesthesignalandnoiseei-gen-values).Firstly,accordingtotheestimationofnoisesubspaceobtainedbythepowermethod,anovelsourcenumberdetectionmethodwithouteigen-decompositionisproposedbasedonQRde-composition.Furthermore,theeigenvectorsofsignalsubspacecanbedeterminedaccordingtoQmatrixandthenthedirectionsofsignalscouldbecomputedbytheESPRITalgorithm.Todeterminethesourcenumberandsubspace,thecomputationcomplexityoftheproposedalgorithmisapproximatedas(2log_2n+2.67)M~3,wherenisthepowerofcovariancematrixandMisthenumberofarrayele-ments.ComparedwiththeSingleVectorDecomposition(SVD)basedalgorithm,ithasasubstantialcomputationalsavingwiththeapproximationperformance.Thesimulationresultsdemonstrateitseffectivenessandrobustness.
简介:ThispaperintroducesamethodforsolvingDOAestimationambiguityinESPRITalgorithmwiththeconventionalbeamformer.Withthehelpofit,foranyspaceoftwosubarrays,thesignalDOAin[-π/2,π/2]canbeestimatedeffectivelybyusingESPRITalgorithm.Finally,somesimulationresultstoverifythetheoreticalanalysesarepresented.
简介:Alow-complexitymethodfordirectionofarrival(DOA)estimationbasedonestimationsignalparametersviarotationalinvariancetechnique(ESPRIT)isproposed.Insteadofusingthecross-correlationvectorsinmultistageWienerfilter(MSWF),theorthogonalresidualvectorsobtainedinconjugategradient(CG)methodspanthesignalsubspaceusedbyESPRIT.Thecomputationalcomplexityoftheproposedmethodissignificantlyreduced,sincethesignalsubspaceestimationmainlyneedstwomatrixvectorcomplexmultiplicationsattheiterationofdatalevel.Furthermore,thepriortrainingdataarenotneededintheproposedmethod.Toovercomeperformancedegradationatlowsignaltonoiseratio(SNR),theexpandedsignalsubspacespannedbymorebasisvectorsisusedandsimultaneouslyrendersESPRITyieldredundantDOAs,whichcanbeexcludedbyperformingESPRIToncemoreusingtheunexpandedsignalsubspace.ComparedwiththetraditionalESPRITmethodsbyMSWFandeigenvaluedecomposition(EVD),numericalresultsdemonstratethesatisfactoryperformanceoftheproposedmethod.
简介:DigitalnetworkedcommunicationsarethekeytoallInternet-of-Thingsapplications,especiallytosmartmeteringsystemsandthesmartgrid.Inordertoensureasafeoperationofsystemsandtheprivacyofusers,thetransportlayersecurity(TLS)protocol,amatureandwellstandardizedsolutionforsecurecommunications,maybeused.WeimplementedtheTLSprotocolinitslatestversioninawaysuitableforembeddedandresource-constrainedsystems.ThispaperoutlinesthechallengesandopportunitiesofdeployingTLSinsmartmeteringandsmartgridapplicationsandpresentsperformanceresultsofourTLSimplementation.Ouranalysisshowsthatgivenanappropriateimplementationandconfiguration,deployingTLSinconstrainedsmartmeteringsystemsispossiblewithacceptableoverhead.
简介:AneffectivemethodisintroducedtocompensatetheeffectsofmutualcouplingfortheEstimationofSignalParameterviaRotationalInvarianceTechniques(ESPRIT)directionfindingalgorithminapplicationofsignalsnapshotarrayprocessing.ChangingthecovariancematrixintoaTeoplitzmatrixcanachievehighresolutionintheDirectionOfArrive(DOA)estimation.Howthemutualcouplingaffectsthearrayantennashasbeendiscussedandanewdefinitionofmutualim-pedancehasbeenusedtocharacterizethemutualcouplingeffectsbetweenthearrayelements.Basedonthenewmutualimpedancematrix,apracticalmethodispresentedtoeliminatetheeffectsofmutualcouplingforESPRITinthesinglesnapshotdataprocessing.Thesimulationresultsshowthat,thisnewmethodnotonlyproperlyreducestheeffectsofmutualcoupling,butalsomaintainsitssteadyperformanceevenforweaksignals.
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简介:Anovelrotationalinvariancetechniqueforblindestimatesofdirectionofarrival(I)OA)andDopplerfrequencywithunknownarraymanifoldduetoarraysensoruncertaintiesisproposed,takingDopplerfrequencydifferencebetweenasuccessivepulsesasrotationalparameter.Theeffectivenessofthenewmethodisconfirmedbycomputersimulation.Comparedwiththeexisting2-DDOA-frequeucyestimatetechniques,thecomputationloadoftheproposedmethodcanbesavedgreatly.