NASATM-1998-206540 Design and Calibration of the X

NASA/TM-1998-206540DesignandCalibrationoftheX-33FlushAirdataSensing(FADS)SystemStephenA.Whitmore,BrentR.Cobleigh,andEdwardA.HaeringDrydenFlightResearchCenterEdwards,CaliforniaJanuary1998Sinceitsfounding,NASAhasbeendedicatedtotheadvancementofaeronauticsandspacescience.TheNASAScientificandTechnicalInformation(STI)ProgramOfficeplaysakeypartinhelpingNASAmaintainthisimportantrole.TheNASASTIProgramOfficeisoperatedbyLangleyResearchCenter,theleadcenterforNASA’sscientificandtechnicalinformation.TheNASASTIProgramOfficeprovidesaccesstotheNASASTIDatabase,thelargestcollectionofaeronauticalandspacescienceSTIintheworld.TheProgramOfficeisalsoNASA’sinstitutionalmechanismfordisseminatingtheresultsofitsresearchanddevelopmentactivities.TheseresultsarepublishedbyNASAintheNASASTIReportSeries,whichincludesthefollowingreporttypes:•TECHNICALPUBLICATION.ReportsofcompletedresearchoramajorsignificantphaseofresearchthatpresenttheresultsofNASAprogramsandincludeextensivedataortheoreticalanalysis.Includescompilationsofsignificantscientificandtechnicaldataandinformationdeemedtobeofcontinuingreferencevalue.NASA’scounterpartofpeer-reviewedformalprofessionalpapersbuthaslessstringentlimitationsonmanuscriptlengthandextentofgraphicpresentations.•TECHNICALMEMORANDUM.Scientificandtechnicalfindingsthatarepreliminaryorofspecializedinterest,e.g.,quickreleasereports,workingpapers,andbibliographiesthatcontainminimalannotation.Doesnotcontainextensiveanalysis.•CONTRACTORREPORT.ScientificandtechnicalfindingsbyNASA-sponsoredcontractorsandgrantees.•CONFERENCEPUBLICATION.Collectedpapersfromscientificandtechnicalconferences,symposia,seminars,orothermeetingssponsoredorcosponsoredbyNASA.•SPECIALPUBLICATION.Scientific,technical,orhistoricalinformationfromNASAprograms,projects,andmission,oftenconcernedwithsubjectshavingsubstantialpublicinterest.•TECHNICALTRANSLATION.English-languagetranslationsofforeignscientificandtechnicalmaterialpertinenttoNASA’smission.SpecializedservicesthatcomplementtheSTIProgramOffice’sdiverseofferingsincludecreatingcustomthesauri,buildingcustomizeddatabases,organizingandpublishingresearchresults...evenprovidingvideos.FormoreinformationabouttheNASASTIProgramOffice,seethefollowing:•AccesstheNASASTIProgramHomePageat•[e-mail]•FaxyourquestiontotheNASAAccessHelpDeskat(301)621-0134•TelephonetheNASAAccessHelpDeskat(301)621-0390•Writeto:NASAAccessHelpDeskNASACenterforAeroSpaceInformation800ElkridgeLandingRoadLinthicumHeights,MD21090-2934TheNASASTIProgramOffice...inProfileNASA/TM-1998-206540DesignandCalibrationoftheX-33FlushAirdataSensing(FADS)SystemStephenA.Whitmore,BrentR.Cobleigh,andEdwardA.HaeringDrydenFlightResearchCenterEdwards,CaliforniaJanuary1998NationalAeronauticsandSpaceAdministrationDrydenFlightResearchCenterEdwards,California93523-0273NOTICEUseoftradenamesornamesofmanufacturersinthisdocumentdoesnotconstituteanofficialendorsementofsuchproductsormanufacturers,eitherexpressedorimplied,bytheNationalAeronauticsandSpaceAdministration.Availablefrom:NASACenterforAeroSpaceInformationNationalTechnicalInformationService800ElkridgeLandingRoad5285PortRoyalRoadLinthicumHeights,MD21090-2934Springfield,VA22161PriceCode:A16PriceCode:A16*VehicleAerodynamicsGroupLeader,AerodynamicsBranch.†AerospaceEngineer,AerodynamicsBranch.‡AerospaceEngineer,AerodynamicsBranch.Copyright1998bytheAmericanInstituteofAeronauticsandAstronautics,Inc.NocopyrightisassertedintheUnitedStatesunderTitle17,U.S.Code.TheU.S.Governmenthasaroyalty-freelicensetoexerciseallrightsunderthecopyrightclaimedhereinforGovernmentalpurposes.Allotherrightsarereservedbythecopyrightowner.1AmericanInstituteofAeronauticsandAstronauticsDESIGNANDCALIBRATIONOFTHEX-33FLUSHAIRDATASENSING(FADS)SYSTEMStephenA.Whitmore,*BrentR.Cobleigh,†andEdwardA.Haering,Jr.‡NASADrydenFlightResearchCenterEdwards,CaliforniaAbstractThispaperpresentsthedesignoftheX-33FlushAirdataSensing(FADS)system.TheX-33FADSusesamatrixofpressureorificesonthevehiclenosetoestimateairdataparameters.Thesystemisdesignedwithdual-redundantmeasurementhardware,whichproducestwoindependentmeasurementpaths.Airdataparametersthatcorrespondtothemeasurementpathwiththeminimumfiterrorareselectedastheoutputvalues.Thismethodenablesasinglesensorfailuretooccurwithminimaldegradingofthesystemperformance.ThepapershowstheX-33FADSarchitecture,derivestheestimatingalgorithms,anddemonstratesamathematicalanalysisoftheFADSsystemstability.Preliminaryaerodynamiccalibrationsarealsopresentedhere.Thecalibrationparameters,thepositionerrorcoefficient(),andflowcorrectiontermsfortheangleofattack(),andangleofsideslip()arederivedfromwindtunneldata.Statisticalaccuracyofthecalibrationisevaluatedbycomparingthewindtunnelreferenceconditionstotheairdataparametersestimated.ThiscomparisonisaccomplishedbyapplyingthecalibratedFADSalgorithmtothesensedwindtunnelpressures.WhentheresultingaccuracyestimatesarecomparedtoaccuracyrequirementsfortheX-33airdata,theFADSsystemmeetstheserequirements.NomenclatureaflushairdatasensinggeometrycoefficientAangleofattacktripl