THE UNIVERSITY OF CALGARY Reliable and Continuous

UCGEReportsNumber20144DepartmentofGeomaticsEngineeringReliableandContinuousUrbanNavigationUsingMultipleGPSAntennasandaLowCostIMU(URL:)byRakeshAmmunjeNayakOctober2000THEUNIVERSITYOFCALGARYReliableandContinuousUrbanNavigationUsingMultipleGPSAntennasandaLowCostIMUbyRakeshAmmunjeNayakATHESISSUBMITTEDTOTHEFACULTYOFGRADUATESTUDIESINPARTIALFULFILMENTOFTHEREQUIREMENTSFORTHEDEGREEOFMASTEROFSCIENCEDEPARTMENTOFGEOMATICSENGINEERINGCALGARY,ALBERTAOCTOBER,2000©RakeshA.Nayak2000iiTHEUNIVERSITYOFCALGARYFACULTYOFGRADUATESTUDIESTheundersignedcertifythattheyhaveread,andrecommendtotheFacultyofGraduateStudiesforacceptance,adissertationentitled“ReliableandContinuousUrbanNavigationUsingMultipleGPSAntennasandaLowCostIMU”submittedbyRakeshAmmunjeNayakinpartialfulfilmentoftherequirementsforthedegreeofMasterofScience.Supervisor,Dr.M.E.Cannon,DepartmentofGeomaticsEngineeringDr.G.Lachapelle,DepartmentofGeomaticsEngineeringDr.N.El-Sheimy,DepartmentofGeomaticsEngineeringDr.L.E.Turner,DepartmentofElectricalandComputerEngineeringDateiiiABSTRACTTheresearchpresentedinthisthesisfocusesonthefeasibilityofusingmultipleantennastoisolateanddetectmultipathonpseudoranges,andtheimpactofusingmultipleantennasalongwithsomestatisticalreliabilitymeasuretodetectblundersonpseudorangemeasurements,suchthatblunderscanberejectedbeforetheycontaminatetheestimatedvehiclepositions.ThelatterpartofthethesisaddressestheintegrationofdifferentialGPS(DGPS)andalowcostIMUforreliableandeffectivenavigationinanurbanvehicularenvironment,whichismotivatedbythesignificantaccuracydegradationthatcanexistduetosatelliteshadingandmultipatheffects.AseriesoftestswereconductedinandaroundCalgarywherebytheshadingeffectsrangedfromopenskytosignificantshadingtoabout30degreesinelevation.FourNovAtelGPSreceiversandantennasalongwithalowcostIMUweremountedontheroofofthevehicle.Theeffectsofmultipath,itstemporalandspatialdecorrelationpropertiesamongcloselyspacedantennasinvariousenvironmentalconditionswerestudied.Statisticaltestwereperformedtodetectmultipathintheformofblunders.Constraintswerealsoappliedbetweenantennastomakeuseoftheinterantennageometry.Animprovementof10%-40%inpositionaccuracyandgreaterthan50%inreliabilitywasachievedunderdifferentconditionsAthree-axismicro-machinedsolid-stateIMUfromSystronDonnerwasthenintegratedwiththesystem.TheresultingintegratedpositionsarecomputedandcomparedwithadigitalroadmapofCalgaryandaccuracystatisticsarepresented.Subsetsofantennas(i.e.one,twoandthreeantennas)areusedwiththeIMUtodeterminetheperformanceasafunctionofthenumberofGPSreceiversutilized.Inaddition,theabilityoftheIMUtobridgeGPSoutages,poorgeometry,andsignificantmultipathisalsoassessed.Theoverallperformanceasafunctionoftheshadingenvironment(openskyversusurban)iscomputedandtheeffectivenessoftheIMUtoaidGPSisdescribed.Thetestresultsshowthatthepositionaccuraciesvarysignificantlywiththenumberofantennasused,thereliabilitytestandalsowithinertialaiding.TheaugmentationofGPSwithINSresultedivinanimprovedavailabilityofposition.Availabilityimprovementsof10%wereobservedbylimitingthepredictionintervalto20sand100%availabilityisachievable,withreducedaccuracyimprovementresultingfromthepoorqualityofsensorsused.vACKNOWLEDGEMENTSIwouldliketoexpressmyheartfeltgratitudetomysupervisorDrElizabethCannon,forhersupport,andguidancethroughoutmyM.Sc.program.IwouldalsoliketothankherforprovidingmetheopportunityformetocomehereandexperiencethepulseofGPSfirsthand.IamalsothankfultoDaimlerChryslerResearchandTechnologyNorthAmericaforfundingmostofthiswork,especiallyMr.ChristopherWilson.IamextremelygratefultoProf.OlegSalychevandDr.VladimirVoronovfortheirpatienceduringtheinnumerablediscussionswehadoninertialnavigationconceptsandsoftware.Iamalsogratefultoallthestaffandthecourseinstructorsforimpartingqualityeducationandmakethisaverymemorablelearningexperience.TherearemanyamongmyfriendswhohavebeentherewheneverIneedsomehelpbothtechnicalandnon-technical.Theseinclude,JayantaRay,SamRyan,MarkPetovello,GeorgiaFotopoulos,LuizFortes,LuoNing,andHumingWu.IamextremelygratefultoKyleO′keefe,RonRamsaran,NagaRavi,andJunjieLiuwithoutwhosehelpthefieldtrialswouldnothavebeenpossible.Thanksguys.AccordSoftwareandSystemsPvtLtd,isalsothankedforintroducingmetotheexcitingfieldofGPS.FinallyIwouldliketothankmyparentsandmybrotherfortheirunconditionalsupportandbeingwithmeandsupportingmeallthroughmylife.viTABLEOFCONTENTSAPPROVALPAGE...........................................................................................................iiABSTRACT......................................................................................................................iiiACKNOWLEDGEMENTS..............................................................................................vTABLEOFCONTENTS.................................................................................................viLISTOFTABLES...........................................................................................................ixLISTOFFIGURES.................