外文翻译原文-无线传感器网络在精准林业中的使用

TheTenthInternationalConferenceonElectronicMeasurement&InstrumentsICEMI2011ApplicationofWSNinprecisionforestryZhangQinghuiLiJunqiuRongJianXuWeihengHeJinpingDepartmentofComputerandInformationScience,SouthwestForestryUniversity650224Kunming,ChinaEmail:AbstractInordertoconvenientlyaccessinformationofforestry,anewtechnology,wirelesssensornetworkisintroducedinprecisionforestryapplications.Aforestryinformationmonitoringsystembasedonwirelesssensornetworktechnologyisproposed,whichcansampletemperature,soilmoisture,lightintensity,nitrogenconcentrationandotherenvironmentalfactors.ThenetworksofsensornodesaremanagedbyacentralnodewhichcollectsandtransmitsdatatoremotehostcomputerthroughGPRS.ThesystemdesignmethodologybasedonZigBeechip2430ispresentedandthecorrespondingsystemhardwarearchitectureandsoftwareflowaregiven.Thissystemeffectivelymakesiteasytocollectandtransmitdataofenvironmentalfactorsinforestryproductandposseshighpracticalvalues.Keywordsprecisionforestry,wirelesssensornetwork,zigbee,CC2430.I.INTRODUCTIONWiththerapiddevelopmentofaseriesofhightechnologiessuchasinformationtechnology,biotechnologyandengineeringtechnology,theconcept“PrecisionForestry”introducedinearly90sisbecomingincreasinglyimportant.Theword,precisionforestryisaforestryproductionprocessinwhichhightechnologiessuchasvisualsensors,satellitepositioningandotherhigh-techsensingandanalyticaltoolsareusedtoobtaintheimmediatedataaboutworkquality,quantityandtiming,andbyanalyzingenvironmentalfactorsaffectthegrowingofforestry,technicallyfeasibleandeconomicallyeffectivecontrolmeasuresaretakentoachievemaximumbenefitsandminimumenvironmentalhazards1.Currently,thedevelopmentofprecisionforestryhaslaggedbehindthedevelopmentofprecisionagriculture.Itisduetosomefeaturessuchaslongercycle,moreinterference,morevariationandmorecomplexconditions,inforestryproduction2.Thesefeaturesmakethecollectionandtransmission,whichisanimportantpartofprecisionforestry,ofenvironmentalfactorsintreegrowthbecomesverydifficult.Therefore,aforestryecologicalenvironmentmonitoringsystemwiththefeaturesoflow-input,low-energy,low-consumption,high-output,high-intelligence,high-informationandhigh-protectionofenvironmentshouldbedeveloped.Now,theemergenceofanewtechnology,wirelesssensornetwork,providesasuitabletechnicalmeansfortherealizationofthisgoal.II.WIRELESSSENSORNETWORKWirelesssensornetwork,whichintegratessensortechnology,MEMStechnology,wirelesscommunicationtechnology,embeddedcomputingtechnologyanddistributedinformationmanagementtechnology,hasbeenunderrapiddevelopmentduringrecentyears.Becauseofthewideapplicationprospect,itintereststheworld.“BusinessWeek”everpredictedin1999thatWSNtechnologieswouldbeoneofthemostimportanttechnologiesin21st3.ZigBeeisalow-powerwirelesscommunicationstechnologydesignedformonitoringandcontrolofdevices.Itisgenerallyconsideredasanoptimalwirelesscommunicationprotocol,becauseitfullymeettherequirementofWSNapplicationandownssuchpropertyashigherreliability,self-organizationnetwork,self-curecapacityandlargenetworkvolume4.OneofZigBeeskeyfeaturesisitsabilitytocoverlargeareaswithrouters.ThisfeaturehelpsdifferentiateZigBeefromothertechnologies.Meshnetworkingextendstherangeofthenetworkthroughrouting,whileselfhealingincreasesthereliabilityofthenetworkbyre-routingamessageincaseofanodefailure.III.SYSTEMARCHITECTUREAstheFigure1shown,theZigBeewirelessnetworksystemadoptstheMeshtopology.Thesensornodesachievereal-timedatasuchastemperature,humidity,soilmoisture,andnitrogenconcentration,andtransmitdatatothecentralnode,coordinator.Whilethesensornodeisfarawayfromthecentralnode,theeveryothernodecanactsasZigBeerouterwhichisabletorelaydatatocentralnode.AllofthedataaredirectedtotheZigBeecoordinatorbywhichthesedataarecombinedandpackedandthentransmittedtothehostcomputerthroughGPRSnetworksallowinginformationtobetransmittedmorequickly,immediatelyandefficientlyacrossthemobilenetwork.Onthehostcomputer,thereceiveddataaremonitored,Fig.1Systemarchitecture_978-1-4244-8161-3/11/$26.002011IEEETheTenthInternationalConferenceonElectronicMeasurement&InstrumentsICEMI2011calculated,analyzedandevaluatedbyanexpertsystem.BasedonZigBeeandGPRS,thisdesignmethodinwhichtheZigBeenodesarewakenupperiodically,effectivelyreducesthepowerconsumptionofeachZigBeesensornodesandtheprobabilityofcollisionswitheachother.ThePCactsashostcomputerandwithwhichtheEthernetinterfaceisusedtorealizeremotemonitor5.IV.HARDWARECIRCUITDESIGNA.ZigBeechipThehardwareofthissystemincludestwoparts:oneisthesensornodeswhichareresponsiblefordataacquisition;theotheriscentralnodewhichisresponsibleforwirelessnetworkmanagementanddatatransmissionandframing.AllofthetwopartstakeCC2430asthecoreofthewirelesstransceiverandprocessingmodule.TheCC2430isatrueSystem-on-Chip(SoC)solutionspecificallytailoredforIEEE802.15.4andZigBeeapplications.Itcombinesaveryexcellenttransceivercorewithanindustry-standardenhanced8051MCU,32/64/128Flash,8KBRAM,ADC,severaltimers,AESsecuritycoprocessor,watchdogtimer,twoUSARTs,andmanyotherpowerfulfeatures6.Becauseofrequiringminimalexternalcircuitrysupport,theCC2430isveryconvenienttouse.Andtakingthemostsignificantadvantageoflowpowerconsumption,theCC2430whichhaslessthan0.6g541Acurrentconsumptioninstandbymode,isverysuitableforbatteryapplications.B.ZigBeehardwarecircuitendpointsThehardwareblockdiagramofsensornodesandcentralnodeisshowninFigure2.Asmentionedabove,theCC2430isveryrichininternalresources,sothecorehardwareisverysimple.ExceptforMCUchip,CC2430,thewholehardwareofsensornodesjustconsistsofthreeparts:sensorcircuit,powersupply,crystalOscillator.Similarly,thecentralnodeiscomposedofthreeparts:GPRSmodule,powersupply,crystalOscillator.Therefore,thehardwaressizeofbothcanbemadeverysmall.Fig.2BlockdiagramofhardwareCC2430integratesa14-bitADCwithuptoeightinputs.Thus,anodecansampleavarietyofdata.Ifthenumberofinputismorethan8orthecontrolcircuitisverycomplicated,anadditionalMCUandADCcanbeaddedtoperformthecorrespondingfunctions.TheMCUcancommunicatewithCC2430throughRS232serialinterface.Thecentralnodeperiodicallywakessensornodesup,andcollectsdatafromthesenodes.Andthen,centralnodepacketsthesedatainaccordancewithpredefinedformatandpassthesedatathroughtheserialporttoGPRSmodule.Finally,hostcomputergetthesedata.Andthenexpertsystemprocessandgraphicallydisplaythesedata.ZigBeecommunicationisworkingat2.4Gband,theantennaisalsousedintherealizationofmicrostriplineonthePCBtoachieve.Therefore,inthePCBdesign,mustbestrictlyreferencemanual;placementandrouting,weshouldalsopayattentiontosplittheanaloganddigitalsignalprocessing.V.SOFTWAREDESIGNA.CC2430firmwaredesignTheCC2430sfirmware,basedonTIZ-Stack,isdevelopedundertheIDEplatform,IAREmbeddedWorkBench.Z-StackreleasedbyTIisaprotocolstackinaccordancewithZigBee2006specifications.WiththehelpofZ-Stack,ourdevelopmentofthefirmwareismainlyaboutapplicationlayer.Inoursystem,centralnodeisinitiatedasZigBeecoordinatorandsensornodesareinitiatedasZigBeerouter.Coordinatoristhecenteroftheentirenetwork,whichisresponsibleforfunctionsincludingtheestablishment,maintenanceandmanagementofnetworks,andallocationofnetworkaddress.ThesoftwareflowchartofcoordinatorisshowninFigure3.Fig.3FlowchartofcoordinatorAtfirst,softwareinitializeclockcircuit,UARTsandIOport,andthenphysicallayer,MAClayer,setPANID,channelandaddressestobuildanetwork.Afterinitializationdone,thecoordinatormonitorRFsignalandassignnetworknumbertonewnode.MeanwhilecentralTheTenthInternationalConferenceonElectronicMeasurement&InstrumentsICEMI2011nodeenablesaninternaltimer.Whentimerexpires,aninterruptserviceroutineiscalledtowakeupsensornodes.Andthencentralnodewaitsfordatareceivedinterrupt.Afteralldatahavebeencollected,centralnodesendsthesedatathroughRS232serialporttoGPRSmodulewhichwirelesslyforwardsreal-timedatatohostcomputerthroughGPRS.ThesoftwareflowchartofsensornodesisshowninFigure4.Sensornodeshardwareinitializationissimilartocentralnodes.Afterjoiningthenetwork,sensornodesentersleepmode,waitingforwakeupcommand.AssoonasgetwakeupRFsignal,sensornodessamplesignalandtransmitdatatocentralnode,andthengobacktosleepmode.Fig.4FlowchartofsensornodesThedatatransmittedbetweencentralnodeandthesensornodes,orbetweencentralnodeandhostcomputer,isinaccordancewithacustomizedframestructurewhichisshowninTable1.Table1FramestructureThesensornodesperiodicallygetenvironmentaldataandpacketthesedata,andthentransmitdatatocentralnodewhichtransferthesedatatohostcomputer.Assoonasthesedatabeingreceived,hostcomputeranalyzethemandgraphicallydemonstratetheminuserinterface.Thefollowingsourcecodefragmentisthesendingfunctionofthesensornode,whichisperiodicallywakenupbycentralnode.And,ifitgetsthesendcommand,thenodepacketscollecteddatainformataccordingtoTable1andsendtheframetophysicallayerprogramwhichwirelesslysentdatatocentralnode.voidWirelessSendData(BYTEframe)switch(frame)casePacket_Send:SendData1=0xff;SendData2=0xff;SendData3=macInfo.longAddr0;SendData4=macInfo.longAddr1;SendData5=8;/datalengthis8for(i=0;i=5;i+)cs+=SendDatai;SendData6=cs;/checksumSendData7=(Paket.Head);SendData8=(Paket.Node);SendData9=(Paket.ForwardNode);SendData10=(Paket.SensorNum);SendData11=(Paket.HighData);SendData12=(Paket.LowData);SendData13=(Paket.End);MACPutArray(SendData,14);MACFlush();break;caseB.SoftwaredesignofhostcomputerProgramofhostcomputerisdevelopedinLabWindowsCVIwhichmakesiteasytocollectdataandillustratedataongraph7.Thesoftware,whoseflowchartisshowninFigure5,record,analyzeandcomparecollecteddata,andgraphicallydisplayonscreen.Fig.5FlowchartofhostcomputerThemaingraphicaluserinterfaceofhostcomputerisshowninFigure6.Thereareseveralbuttonsplacedontherightofthepanel.Theusercanobserveandcompare,ingraphicalway,thesameenvironmentalparameterofdifferentsensornodesbyclickingonthebuttons.Figure7illustratestemperaturewaveoffoursensornodesin12hours.HeaderNodeNO.TransfernodeNO.FunctionNO.DataChecksum8bit8bit16bit8bit16bit8bitTheTenthInternationalConferenceonElectronicMeasurement&InstrumentsICEMI2011Fig.6MainuserinterfaceFig.7Temperaturewaveformsofg73g82g88g85nodesInaddition,usercangetallenvironmentalparametersofonespecificnodebyclickingtheroundbuttons,markedbydigitalnumber,inthemap.Figure8showstemperature,humidity,illuminanceandconcentrationofcarbondioxideofnode2.Fig.8Waveformofnode2VI.CONCLUSIONTakingadvantagesoftheZigBeewirelesssensornetwork,thissystemwhichislow-cost,lowpowerconsumption,intelligent,easytomaintain,lowenvironmentalpollution,accomplishmonitorofenvironmentalparametersinforestryareas.Moreover,justbyaddingappropriatesensors,thesystemwhichisexpectedtoachievemorefunctionality,iseasytobeextendedinremotecontrolandautomaticcontro