一種改進的基于RSSI測距的室內(nèi)三維修正定位算法

一種改進的基于RSSI測距的室內(nèi)三維修正定位算法摘要：本文提出了一種改進的基于RSSI測距的室內(nèi)三維修正定位算法，該算法通過利用RSSI信號傳輸特性并結(jié)合室內(nèi)地圖信息，實現(xiàn)對移動終端在室內(nèi)三維空間的精確定位。首先，建立包含信號強度值和位置信息的RSSI數(shù)據(jù)庫，并采用加權(quán)平均法對測距誤差和信號衰減進行修正，從而提高定位準確度；其次，利用三角定位原理結(jié)合加速度傳感器對平面位置進行修正，并結(jié)合高度傳感器對垂直位置進行修正，實現(xiàn)了對移動終端在三維空間的定位。實驗結(jié)果表明，該算法能夠較好的處理室內(nèi)復(fù)雜環(huán)境下的信號傳輸問題，并實現(xiàn)對三維空間的精確定位。關(guān)鍵詞：RSSI測距、三維定位、加權(quán)平均法、三角定位原理、加速度傳感器、高度傳感器IntroductionWiththedevelopmentofinformationtechnology,thelocation-basedserviceshavebecomeanimportantpartofpeople'sdailylife.However,thetraditionalpositioningtechnology,suchasGPS,isnotaccurateenoughinindoorenvironmentsduetotheobstaclesandinterference.Therefore,theresearchonindoorpositioningtechnologyhasbecomeahottopicinrecentyears.RSSI-basedpositioningtechnologyhasbecomeoneofthewidely-usedindoorpositioningtechnologiesbecauseofitslowcostandeaseofdeployment.However,RSSI-basedpositioningtechnologystillfacessomechallenges,suchassignalpropagationcharacteristicsandsignalinterference.ThetraditionalRSSI-basedpositioningalgorithmusuallyestimatesthepositionofamobiledeviceintwodimensions,whichcannotmeettherequirementsofindoorthree-dimensionalpositioning.ThispaperproposesanimprovedRSSI-basedindoorthree-dimensionalpositioningalgorithm,whichutilizesRSSIsignaltransmissioncharacteristicsandindoormapinformationtoachieveprecisepositioningofmobiledevicesinindoorthree-dimensionalspace.MethodologyTheproposedalgorithmconsistsoftwomainparts:RSSIdatabaseconstructionandthree-dimensionalpositioningcorrection.1.RSSIDatabaseConstructionTheRSSIdatabaseincludesthesignalstrengthvaluesandthecorrespondinglocations.ThesignalstrengthisobtainedbymeasuringtheRSSIvaluesoftheWi-Fisignalsreceivedbythemobiledevice.Thelocationinformationcanbeobtainedbyusingthepositioningtechnologywithhighprecision,suchasGPS.TheRSSIdatabaseisconstructedbycollectingRSSIvaluesandassociatedlocationinformationindifferentpositionsintheindoorenvironment.TheRSSIvaluesreceivedbythemobiledeviceareaffectedbyvariousfactors,suchasdistance,obstacles,walls,andreflections.ToeliminatetheerrorintheRSSIvaluescausedbythesefactors,aweightedaveragingmethodisused.TheweightedaveragingmethodassignslessweighttotheRSSIvalueswithhighernoiselevelsandhigherweighttotheRSSIvalueswithlowernoiselevels.Inthisway,theaverageRSSIvaluescanreflectthetruesignalstrengths.2.Three-dimensionalPositioningCorrectionTheproposedalgorithmcorrectsthetwo-dimensionalpositionobtainedfromtheRSSI-basedpositioningalgorithmusingtheprincipleoftriangulationandtheinformationprovidedbytheaccelerometerandthealtimeter.Thepositioncorrectionprocesscanbedividedintotwoparts:thefirstpartisthecorrectionoftheplanarposition;thesecondpartisthecorrectionoftheverticalposition.TheplanarpositioncorrectionisachievedbytriangulationusingtheinformationobtainedfromthreeormoreAPs.ThepositionofthemobiledevicecanbeobtainedbycalculatingtheintersectionofthreeormorecircleswithcentersattheAPsandradiiequaltothedistancesobtainedfromtheRSSIvalues.However,thiscalculationmayresultinlargeerrorsduetothenoiseinthedistancemeasurements.Toreducetheerror,theweightedaveragemethodisappliedagaintocalculatetheadjusteddistance.Theverticalpositioncorrectionisachievedbyusingtheaccelerometerandthealtimeter.Theaccelerometercanmeasuretheaccelerationofthemobiledeviceinthreedimensions,andthealtimetercanmeasuretheheightofthemobiledevicerelativetotheground.Thecorrectedverticalpositionisobtainedbycombiningthealtitudevalueobtainedfromthealtimeterandtheaccelerationvalueobtainedfromtheaccelerometer.ResultsTheproposedalgorithmwasevaluatedinarealindoorenvironment.Theexperimentalresultsshowthattheproposedalgorithmcanachieveaccuratethree-dimensionalpositioninginindoorenvironments.ComparedwiththetraditionalRSSI-basedindoorpositioningalgorithm,theproposedalgorithmhasthefollowingadvantages:1.TheuseoftheweightedaveragingmethodcaneliminatetheerrorintheRSSIvaluescausedbysignalpropagationandobstacles.2.Theuseoftheaccelerometerandthealtimetercancorrecttheverticalposition,whichgreatlyimprovestheaccuracyofthethree-dimensionalpositioning.ConclusionThispaperproposesanimprovedRSSI-basedindoorthree-dimensionalpositioningalgorithm,whichutilizesRSSIsignaltransmissioncharacteristicsandindoormapinformationtoachieveprecisepositioningofmobiledevicesinindoorthree-dimensionalspace.Theproposedalgorithmcombinestheweightedaveragingmethod,theprincipleoftriangulation,andtheinformationprovidedbythe