introduction to araim - stanford university separation algorithm vpl gps galileo beidou glonass...
TRANSCRIPT
IntroductiontoAdvancedRAIM
JuanBlanch,StanfordUniversityJuly26,2016
Satellite-basedAugmentationSystems
Credit:ToddWalter
ReceiverAutonomousIntegrityMonitoring(556mHorizontalErrorBound)
4
Signalsusedbyaviationin2016
constellations signals
5
Signalsthatmaybeusedbyaviationusersin2025
constellations signals
+betterclocksandorbitdetermination
Bestuseofmulti-constellationmulti-frequencyforaviation?IfRAIMcouldbeextendedtoverticalnavigation:
• Worldwidecoverageofthemoststringentoperations• ArcticNavigation• NoneedforGEOsatellites• Norealtimegroundmonitoringnetwork
Whatdowewant?
• Accuracy• Integrity• Continuity
P x̂v − x > Alert Limit & no alert( ) ≤10−7
( )ˆ 1.8 mv vstd x x
P alert( ) ≤ 8×10−6
Whatdowefear?
• Faults• Nominalconditions
ThreatModel
ThreatmodelNominal Narrowfault Widefault
ClockandEphemeris Orbit/clockestimationandpredictionandbroadcastlimits
Includesclockrunoffs,badephemeris,unflaggedmanoeuvres
ErroneousEOPP,inadequatemannedops,ground-inherentfailures
SignalDeformation NominaldifferencesinsignalsduetoRFcomponents,filters,andantennaswaveformdistortion
Failuresinsatellitepayloadsignalgenerationcomponents.FaultedsignalmodelasdescribedinICAO
N/A
Code-CarrierIncoherence
e.g.incoherenceobservedinIIFL5signalorGEOL1signals
e.g.incoherenceobservedinIIFL5signalorGEOL1signals
N/A
Interfrequency Biases Delaydifferencesinsatellitepayloadsignalpaths
DelaydifferencesinsatellitepayloadsignalpathsTBC
N/A
SatelliteAntennaBias Look-angledependentbiasescausedatsatelliteantennas
Look-angledependentbiasescausedatsatelliteantennas
N/A
Ionosphere N/A Scintillation Multiplescintillationsatsolarstorms
Troposphere Nominaltroposphereerror(afterapplyingSBASMOPSmodelfortropo correction)
N/A N/A
ReceiverNoiseandMultipath
Nominalnoiseandmultipathtermsinairbornemodel(TBCGailleoBOC(1,1)andL5/E5a))
e.g.:receivertrackingfailureormultipathfromonboardreflector.TBC
e.g.:receivertrackingmultiplefailureormultipathfromonboardreflector.TBC
From:WorkingGroupC,ARAIMTechnicalSubgroup,InterimReport,Issue1.0,December19,2012http://ec.europa.eu/enterprise/newsroom/cf/_getdocument.cfm?doc_id=7793
http://www.gps.gov/policy/cooperation/europe/2013/working-group-c/ARAIM-report-1.0.pdf
GLONASSconstellationwidefault
April1-2,2014
Credit:ToddWalter
GPSServicehistory:Nominalclockandephemeriserrors(2009-2014)
Credit:ToddWalter
MappingthethreatmodelintotheIntegritySupportMessage
Nominal Narrowfault WidefaultClockandEphemeris Orbit/clockestimationand
predictionandbroadcastlimitsIncludesclockrunoffs,badephemeris,unflaggedmanoeuvres
ErroneousEOPP,inadequatemannedops,ground-inherentfailures
SignalDeformation NominaldifferencesinsignalsduetoRFcomponents,filters,andantennaswaveformdistortion
Failuresinsatellitepayloadsignalgenerationcomponents.FaultedsignalmodelasdescribedinICAO
N/A
Code-CarrierIncoherence
e.g.incoherenceobservedinIIFL5signalorGEOL1signals
e.g.incoherenceobservedinIIFL5signalorGEOL1signals
N/A
Interfrequency Biases Delaydifferencesinsatellitepayloadsignalpaths
DelaydifferencesinsatellitepayloadsignalpathsTBC
N/A
SatelliteAntennaBias Look-angledependentbiasescausedatsatelliteantennas
Look-angledependentbiasescausedatsatelliteantennas
N/A
Ionosphere N/A Scintillation Multiplescintillationsatsolarstorms
Troposphere Nominaltroposphereerror(afterapplyingSBASMOPSmodelfortropo correction)
N/A N/A
ReceiverNoiseandMultipath
Nominalnoiseandmultipathtermsinairbornemodel(TBCGailleoBOC(1,1)andL5/E5a))
e.g.:receivertrackingfailureormultipathfromonboardreflector.TBC
e.g.:receivertrackingmultiplefailureormultipathfromonboardreflector.TBC
From:WorkingGroupC,ARAIMTechnicalSubgroup,InterimReport,Issue1.0,December19,2012http://ec.europa.eu/enterprise/newsroom/cf/_getdocument.cfm?doc_id=7793
http://www.gps.gov/policy/cooperation/europe/2013/working-group-c/ARAIM-report-1.0.pdf
σURA,i
Psat,i Pconst,jbnom,i
σtropo,i
σairborne,i
SolutionSeparationAlgorithm
VPL
GPS
Galileo
Beidou
GLONASS
VPLVPLVPL
Blanchetal"AdvancedRAIMuserAlgorithmDescription:IntegritySupportMessageProcessing,FaultDetection,Exclusion,andProtectionLevelCalculation,"Proceedingsofthe25thInternationalTechnicalMeetingofTheSatelliteDivisionoftheInstituteofNavigation(IONGNSS2012),Nashville,TN,September2012
AdvancedRAIMconcept
VPL
Pconst,1
Pconst,2
IntegritySupportMessage:
σURA,i
Pconst,jσURA,i Psat,i
Pconst,3
Psat,i
IntegritySupportMessageParameter Description Value Size
(bits)
DataHeader
ISM_WN ISMWeek Number [0, 1, … 1023] 10
ISM_TOW ISM Time of Week (hours) [0, 1, … 167 ] 8
ANSP ID Service Provider Identification [0, 1, … 255] 8
Criticality Usable for Precise/Vertical? [0, 1] 1
Total Header = 27 bits
PerConstellationParameters Maski 32 bits indicating whether an SV is valid for ARAIM (1)
or not (0)[m1, m2, … m32] 32
Pconst,i Probability of constellation fault at a given time [10-8, 10-5, 10-4, 10-3] 2
Psat,j Probability of satellite fault at a given time [10-6, 10-5, 10-4, 10-3] 2αURA,j Multiplier of the URA for integrity [1, 1.25, 1.5, 2, 2.5, 3, 5, 10] 3
αURE,j Multiplier of the URA for continuity & accuracy [0.25, 0.5, 0.75, 1, 1.25, 1.5, 2, 4] 3
bnom,j Nominal bias term in meters [0.0:0.25: 2.5,, 3, 4, 5, 7.5, 10] 4
Total Core = 46 bits x 4 Constellations = 184 bits
WouldfitinoneSBASmessage(250bits),orinoneGPSCNAVmessage(300bits)
Multi-constellationL1-L5ARAIMavailabilitymap
GPS24– Galileo24
URA=1m
Pconst =10-4
VerticalARAIM:L1-L5performance
Constellation/URA .5m .75m 1m 1.5m 2m
Depleted(GPS23– GAL23) 88.1 86.1 81.3 38.1 0
Baseline(GPS24– GAL24) 100 100 98.8 88.2 3
Optimistic(GPS27– GAL27) 100 100 99.8 94.9 21.8
Constellationwidefaultismitigatedbytheresidualscheck:Pconst =10-4
LPV-200
Constellation/URA .5m .75m 1m 1.5m 2m
Depleted(GPS23– GAL23) 94.0 91.8 87.7 75.0 35.4
Baseline(GPS24– GAL24) 100 100 100 99.0 89.5
Optimistic(GPS27– GAL27) 100 100 100 100 93.85
LPV-250
17
HorizontalARAIMwithGPSonly(matchescurrentRAIMperformance)
HorizontalARAIMwithGPSandGLONASS
Summary
• AdvancedRAIMisanaturalandverypromisingmethodtoexploitmulti-constellationGNSS.
• Itwillimprovedramaticallyhorizontalperformanceandmayprovideverticalguidance
• AdvancedRAIMisconceptuallysimple(attheuserlevel)
• ChallengesremainforthedeterminationoftheIntegritySupportMessage
Reportsandpublications• WorkingGroupC,ARAIMTechnicalSubgroup,InterimReport,Issue1.0,December19,2012.
Availableat:http://ec.europa.eu/enterprise/newsroom/cf/_getdocument.cfm?doc_id=7793http://www.gps.gov/policy/cooperation/europe/2013/working-groupc/ARAIM-report-1.0.pdf
• GPS-GalileoWorkingGroupCARAIMTechnicalSubgroupMilestone2Report,February11,2015.Availableat:
http://www.gps.gov/policy/cooperation/europe/2015/working-group-c/http://ec.europa.eu/growth/tools-databases/newsroom/cf/itemdetail.cfm?item_id=8191
Otherpublications:• Walter,Todd,Blanch,Juan,"CharacterizationofGNSSClockandEphemerisErrorstoSupportARAIM,"ProceedingsoftheION2015PacificPNT
Meeting,Honolulu,Hawaii,April2015,pp.920-931.
• Blanch,J.,Walter,T.,Enge,P.,Kropp,V.,”ASimplePositionEstimatorthatImprovesAdvancedRAIMPerformance,”IEEETransactionsonAerospaceandElectronicSystems Vol.51,No.3,July2015.
• Blanch,J.,Walter,T.,Enge,P.,Lee,Y.,Pervan,B.,Rippl,M.,Spletter,A.,Kropp,V.,"BaselineAdvancedRAIMUserAlgorithmandPossibleImprovements,"IEEETransactionsonAerospaceandElectronicSystems,Volume51,No.1,January2015.
• Blanch,J.,Walter,T.,andEnge,P.,”Results ontheOptimalDetectionStatisticforIntegrityMonitoring,”ProceedingsoftheInstituteofNavigationInternationalTechnicalMeeting2013,SanDiego,January2013.SubmittedtoNAVIGATION.
• Phelts,R.E.,Blanch,J.,Walter,T.,Enge,P.,"TheEffectofNominalSignalDeformationBiasesonARAIMUsers,"Proceedingsofthe2014InternationalTechnicalMeetingofTheInstituteofNavigation,SanDiego,California,January2014,pp.56-67.