"Radio Navigation and Radio Communication - Synergies and Conflicts"
Marconi/SCPNTPanel
PanelModerator:BradParkinson
Panelists:IrwinJacobs,VintCert,JohnCoffi,Mar?nCooper&DavidPayne
Use of Radio Waves - Noteworthy Characteristics Communica?ons
• DigitalCommunica.ons–resolvingsequenceof“0sor1s”
• WideRFbandwidthandhighpowertomaximizedatabandwidth,constrainedby“ShannonLimit”inthepresenceofnoise
• Userscanbepassive(broadcas.ng)orac.ve(full-duplex)
• TransmiKngusersareusuallyeasilyiden.fied
• ExplosivegrowthindemandforBandwidth
• New802.11acspecmayallowprecisionindoorposi.oning
Posi?oning&Timing• PrecisionTiming(mul.-latera.on)orSignal
Direc2on(orboth)arekeyparameters
• Keymeasurementisbittransi2on2me(forrangingtypesystems)
• “SignalSequence”alreadyknown
• WideBandwidthtoachieve.ming(andhenceranging)precision
• Useofprocessinggain(anaveragingtechnique)toachieveJammingResistance
• ForpassiveUsers(e.g.GPSoreLoran),cannotdeterminenumberorloca.ons
• SatelliteNaviga.onsignalsareextremelyweak
Use of Radio Waves – Selected Techniques/Applications
Communica?ons• CellPhones(2-way)• FiberOp.cCable-majordistribu.ontechnique
• TV–bothsatelliteandterrestrial
• HF/ShortWave–longrangecommunica.ons
• NextGenera.on5G
Posi?oningandTiming• TimeSynchroniza.on
• Mostapplica.onsrequiremul.ple,.me-synchronizedtransmiaerloca.ons
• ForGNSS/GPS,signalstrengthisveryweakbutgives24/7Globalcoverage
• GPSreceiversnowapparentlyover3.5Billion–mostlysmartphones
• Hi-precisionGPSannualvaluetoUSover$35B
Areas Exampleapplica?ons Avia?on Areanaviga.on,approach,landinguptoCatIII,WAAS,NextGen Agriculture AutoFarming:cropspraying,precisioncul.va.ng,yieldassessment Automo?ve Turn-by-turnguidance,OnStar,driverlesscars Emergency&RescueServices
911,ambulance,fire,police,rescuehelicopters,emergencybeacons,airplaneandshiplocaters,OnStar
IntelligentTransporta?on
Traincontrolandmanagement,UAVs,Intelligenthighways
Military Rescue,precisionweapondelivery,unitandindividualloca.on Recrea?on GeoCaching,controlofmodels,hiking,outdoorac.vi.es Robo?cs&MachineControl
Bulldozers,Earthgraders,miningtrucks,oildrilling
Scien?fic Earthmovementandshape,atmosphere,weatherforecas.ng,climatemodeling,ionosphere,spaceweather,tsunamiwarning,soilmoisture,oceanroughness,windvelocity,snow,ice,andfoliagecoverage,……
SurveyandGIS Mapping,environmentalmonitoring,taggingdiseaseoutbreaks Timing Cellphonetowers,banking,powergrid
Tracking Fleets,assets,equipment,shipments,children,Alzheimer’spa?ents,wildlife,animals,lawenforcements,criminals,parolees,……
PNT Applications – Major Dependency on Comm is in Red
Major Synergies –Nav and Com • CellPhonesandTowers
• SynchronizeTime• ProvidequickGPSPosi.on
• AirTrafficControl• UAVs(Vehicleguidance,TrafficControl,RegulatoryCompliance)• WAAS(IntegrityVerifica.on,Differen.alcorrec.ons)• NextGen(Automa.cdependentSurveilance)
• FirstResponders(Police,Fire,Ambulance)• DispatchandTracking• UrbanCanyonsChallnge
• LocalandRegionalDifferen.alCorrec.onLinks
Status of IEEE 802.11 NGP Study Group Next Generation Positioning (NGP)
FromJuly2015Mee.ng:
• “ExpectedHorizontalAccuracy:XYaccuracyexpectedfortheusecasetosucceed,<1m@90%isarequirementisthatthecomputedloca.onbewithin1mhorizontallyoftheactualloca.on90%ofthe.me”
• “ExpectedVer.calAccuracy:Zaccuracyexpectedfortheusecasetosucceed,“samefloor@99%”isarequirementisthatthecomputedloca.onbeonthesamefloorastheactualloca.on99%ofthe.me.“0.5m@90%”isarequirementisthatthecomputedloca.onbewithin0.5mver.callyoftheactualloca.on90%ofthe.me”
• Usecasesnotyetproven…
Another synergy – use of 802.11ac for indoor positioning
Conflicts
• ScarceSpectrum(FCCAlloca.ons)• InadvertentInterference(OOB)• CollateralDamage(e.g.tryingtojamCommandalsotakeoutPosi.oning–orreverse)
• PassiveNav(noComm)versustwo-wayNav
0
1
1400 1450 1500 1550 1600 1650
FrequencyinMegaHertz
FrequencyAlloca2onsinGPSFrequencyVicinity
- Proposed:- 40,000TerrestrialBroadband
Transmi\ers
- -5BillionTimesGPSPowerat¼Mile
GPSBand
Problems:Proximity(geographicandRFspectrum)
andPower
Lo-Performance,Narrow-BandGPSReceiversmaybe
madetocopewithHi-PowerAdjacentTransmiaeres
Full-BandGPS
Exis.ngHi-Performance,Full-BandGPSReceiversare
JammedNoKnownSimpleFix(swapoutin10years?)
ScarceSpectrumCom/NavConflict:-Poten.alFCCAuthorizedrepurposingofSpectrum
X
?
Visualizing the Problem - Equivalent Power Ratio
Hi-Power Terrestrial - ¼ mile from GPS
HiPowerTerrestrialNiagara~1BillionWaas
(167feetdropwith64,750cubicfeet/second)
5
Feet
GPS-0.2Waas
(1Tablespoonofwaterpersecondthrough5feet)
SamePowerRa?oof5BilliontoOne
Major Questions
• WhatcancellphonesdotocopewithjammingofPNT?Doesitmaaer?
• CanadjacentbandTerrestrial,wide-bandCommunica.ons(e.g.Ligado)becompa.blewithGPS/GNSS?
• Will5Gor802.11acchangethesynergiesbetweenNavandCom?
• Withthenear-futureadventoffourmajorGNSS,doestheinternetorcellphonesbenefit?
Backups
Adjacent band interference
12
Why the Strong Reaction to changing the adjacent band to high-power applications? • GPSuserssupporttheintroduc?onof
Broadband,butnotattheexpenseofthefounda?onsofGPS-
• HipowerneighborsthreatensGPSavailability,accuracyand (mostimportant)Integrity
WhileDigitalCommunica?onsandDigitalNaviga?on
aresuperficiallysimilar,therearesomefundamentaldifferencesthatmustbeunderstood…
13 GPS - Accuracy with Integrity
Summary: Potential Technical Issues and Solutions
March 2011 LightSquared Nationwide Interference with GPS 14
• Maybefuturetechnicalsolu.onsgoodenoughtodiminish"leakage".(sensi.vityofGPSreceiverstotransmiaedpowerintheLightSquaredband.)
• Suchsolu.onsnotimplementedincurrentGPSreceivers-somewillbeok,andmanyotherswillnot.
• IncreasedfutureGPSreceiverCostandGPSaccuracydegrada.onsTBD
• Secondissueistrespassing.(intrusionofLSQsignalsintotheGPSband.)• FilteringLSQmodula2onmaytheore2callymakethistypeofinterferenceacceptable.• Non-linearandothereffects("duc.ng")maynegatefiltereffec.veness• Evalua.onrequiresrealdata-fromrealLSQtransmiaers.
• allranges,azimuths,andeleva.ons.
• Alsocityareaswherereflec.onscanreinforcesignalpower.
• Thebigpoint:StoptherushtoLSQimplementa?on.Objec?velyevaluate:1. TotalimpactoncurrentGPSreceivers2. Impactofforcingsolu?onsonfutureGPSreceivers
• NoDeploymentofLSQTransmi\ersun?lafullna?onaldialogiscomplete
Oncedeploymentisbegun,itwillbedifficulttoreverseit.Notethatwearehavingdifficultyininevenforcingareasonabledelaytoallowfullevalua?onofthesitua?on.
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