gnss availability accuracy reliability gps …f_curry.pdf · integrity monitoring algorithms...

Chronos Technology Ltd, Stowfield House, Upper Stowfield, Lydbrook, Gloucestershire, GL17 9PD

www.chronos.co.uk T: +44 (0) 1594 862200, F: +44 (0) 1594 862211125/03/2010

GPS Interference Detection & Mitigation

Charles Curry, B.Eng, FIET

MD – Chronos Technology Ltd

GAARDIANGNSSAVAILABILITYACCURACYRELIABILITY

anDINTEGRITYASSESSMENT

for TIMING andNAVIGATION

A Technology Strategy Board funded collaboration



The GAARDIAN Project - GPS Interference Detection & Mitigation

GNSS Availability, Accuracy, Reliability anD Integrity Assessment for Timing and Navigation

Research Data Gathering necessary to create a GPS Interference Detection & Mitigation (IDM) network

At point of use, 24x7x365for mission & safety critical applicationsWhich use GPS (or GNSS) signalsLeveraging eLoran signals for QoS determination

UK Government Funded R&D Project (>£2m)through Technology Strategy Board

GNSS – Global Navigation Satellite Systems – e.g. GPS, Glonass, Galileo, Compass, QZSS

QoS – Quality of Service



USCG – US Coast Guard

NANU – Notice Advisory to Navstar Users



Background & MotivationChronos had experienced GPS anomalies - 2005

InterferenceMultipath

Started talking to Academia - 2006University of Bath (UoB)

Started watching UK eLoran renewal project - 2006General Lighthouse Authorities (GLA)

Started a group of like minded organisationsGLA, UoB, NPL, BT

Identified a Technology Strategy Board Grant programmeCreated the GAARDIAN consortiumBid 2007, Awarded Q3 2008Commenced Q4 2008

NPL – National Physical Laboratory



Multipath DetectionTime Interval Error (TIE) very sensitive to multipath events

All Data - Test Friday 11th Aug

-100

-50

0

50

100

150

200

9403

694

834

9563

110

0429

1012

2710

2025

1028

2210

3620

1044

1710

5216

1100

1311

0811

1116

0811

2406

1132

0411

4002

1147

5911

5556

1203

5412

1152

1219

5012

2747

1235

4512

4342

1251

4112

5938

1307

3613

1533

1323

3113

3129

1339

2713

4724

1355

2214

0319

1411

1814

1915

1427

1314

3510

1443

0814

5106

1459

04

UTC Time = BST - 1 Hour

TIE Satellites in track GGA HDOP GSA VDOP Timing Acc POLYP VDOP POLYP PDOP

Re-Rad turned off

Re-rad turned back

on

Moved antenna from a direct line with re-rad to

closer to window so there was a clear multi-

path view



The GAARDIAN - PartnersGLA – General Lighthouse Authorities

User Community - MaritimeeLoran

Imperial College London - Dept of Civil EngUser Community - TransportIntegrity Monitoring Algorithms

University of Bath - Dept of Electrical & ElectronicsGPS & Space Weather

BT – Adastral Research LaboratoriesUser Community – Telecoms

Ordnance SurveyUser Community – Land Geolocation

NPL – National Physical LaboratoryTime, UTC Traceability

Chronos Technology LtdReal time Timing measurement to ns granularityGPS products, components & system integrationGAARDIAN Project Leader



Real Time GNSS & eLoran Integrity Monitoring at Point of Use

GAARDIAN – is aimed at Mission/Safety Critical UsersA mission or safety-critical system is a system whose failure or malfunction may result in:

Death or serious injury to people, or Loss or severe damage to equipment, or Environmental harm

GAARDIAN – The Challenges!Manage vast amounts of data from within PNT enginesIn real timeReport unambiguous integrity, accuracy, continuity, reliabilityObserving many different parametersIn all environments and service denial situations

PNT – Positioning, Navigation & Timing



GAARDIAN – How will PNT Systems be affected?

Different systems will exhibit different vulnerabilitiesSome systems may be unaffected

Different user groups will be susceptible to different vulnerabilities

Some industries do build in mitigationVulnerabilities will be evident at different times

Environmental impact – weather, space weatherSatellite visibilityLocal infrastructureUser movement

Problems will not be systematic or deterministic



GAARDIAN – Mission & Safety Critical UsersEmergency ServicesMilitaryHomeland SecurityTransport – Marine, Road, Rail, AirGovernmentCommunications NetworksPower UtilitiesContainer TerminalsAsset Tracking…………

GPS silicon now costs €3!So new products proliferating!



GAARDIAN – DeliverablesDevelop 24x7 web enabled IDM sensors

IDM – Interference, Detection & MitigationWhich can be deployed as networks

Locally deployed networks of IDM sensors in the vicinity of the userGAARDIAN will deploy trial sensors to analyse dataReduce data at source without losing “content”Heartbeats and “Event” communication back to ServerStore for user viewing over internet

Enable Real-Time GPS, Galileo, Glonass or eLoran (PNT) monitoringFor Mission/Safety critical users at point of use

GAARDIAN Server

Users



eLoranGPRSLANWAN

TIEComparison

GPS

Linux PCEmbeddedAlgorithms

GAARDIAN – IDM SensorIDM Sensors based on Chronos SyncWatch probes

Watching GPS & eLoran SignalsTime Interval Error (TIE) Monitoring between PNT signals from BTEmbedded Linux to process TIE and PNT data

Algorithms from CTL, GLA, ICL and UoBEvent severity and manageability discriminationAdaptive thresholds

Communications to Server via GPRS, LAN or WAN24x7 warning of events

Rb



GAARDIAN – What we will monitor?

GPSNavigation MessageSignal to NoiseCarrier to NoiseDoppler FrequencyCarrier PhasePseudorangeTotal Electron Count1pps

eLoranTime of ArrivalSignal to NoiseEnvelope to Cycle DifferenceAdditional Secondary Factors1pps

3rd Party DataUSCG NANUDifferential GPS DataDifferential Loran Data



PNT Vulnerabilities – What are the Causes?IDM Sensors will assess the following……

InterferenceScintillationMultipathJammingSpoofing Space WeatherWeather (eLoran)Additional Secondary Factors (ASF) (eLoran)Renewal & Upgrade Events



Interference

Photo courtesy of BT

GSM / 3GMobile

MicrowaveLinks

EquipmentCabins

Paging

EngineRoom

GPS



MultipathSignal reaches receiver using different routes“Reflected” route longer GPS Receiver reports wrong location or speed



JammingDeliberate & Accidental

Terrorists, ThievesMilitary, Homeland SecurityDesigns on the webCommercially available!

San Diego IncidentNo GPS in San Diego for 2 hours!http://forums.groundspeak.com/GC/index.php?showtopic=160821http://mg.gpsworld.com/gpsmg/article/articleDetail.jsp?id=418420#H2

Try Google & You-Tube!

http://forums.groundspeak.com/GC/index.php?showtopic=160821

http://forums.groundspeak.com/GC/index.php?showtopic=160821

http://mg.gpsworld.com/gpsmg/article/articleDetail.jsp?id=418420#H2

http://mg.gpsworld.com/gpsmg/article/articleDetail.jsp?id=418420#H2



Space Weather

Solar FlaresIonising radiation hits EarthCauses Aurora BorealisIonospheric disturbances disrupt GPS signalsReport incorrect location

or even loss of lock



Solar CycleCurrently in Solar Minimum11 Year cyclesHave not experienced major solar maximum since GPS has become an everyday utilitywww.spaceweather.comNext Solar Maximum – May 2013!

http://www.spaceweather.com/



PNT Renewal & Maintenance ProgramsInterference from L5 Transponder on SV49

Caused SV49 to appear 150m too low!Delays in renewal program

Probability of maintaining 24 satellites will fall below 95% -2010 - 2015May fall as low as 80%

LORAN station outageseLORAN station renewal program

Depending on strategic reviewPolitics!!



Interference Detection & Mitigation24x7 Real-Time Detection enables appropriate Mitigation

TimelyProportionate

Lie Back and Enjoy!Get the FCC on the case!Is it Red Team or Blue Team?

Test & compare different GNSS receivers with different mitigation capabilityTest & compare different Loran receivers Assess accuracy of differential corrections at point of use



GAARDIAN ProjectWe are moving GPS IDM activity from scientific research into everyday use

Evolving high cost complex scientific analytical systems to low cost industrial/commercial products

Realise an easily deployable network of sensorsIn vicinity of mission safety critical applicatione.g. Airports, Road Systems, DocksAnywhere where GPS is leveraged into critical infrastructure

IDM sensors will filter data and report anomalies to central serverServer alerts users when there is an anomalyUsers access data from server via Internet from any location

See the concept in action on www.syncwatch.com for the telecom industryMonitoring recent Loran outages in Europe – 28th Sept to 9th Oct

http://www.syncwatch.com/



For Further Information contact:-

[email protected]

or any of the partners

or visitwww.gps-world.biz/gaardian/index.php

mailto:[email protected]

http://www.gps-world.biz/gaardian/index.php

gnss availability accuracy reliability gps …f_curry.pdf · integrity monitoring algorithms...

Documents