Implications of GNSS SiS Disruption on Safety of PBN
Operations – Risks, Solutions and Steps Forward
Non-Intentional & Intentional RFI of the GNSS SiS
Silvio Semanjski - Royal Military Academy Belgium
Royal Military Academy Belgium
Content
GNSS SiS disruption - Extent of risks
ECTL and ICAO activities on GNSS SiS disruption
Mitigation of GNSS SiS disruption
GSINTA Project
Safety Assessment with Scenarios of GNSS deteriorated environment
Proposed steps forward
1st ICAO PBN TF & ECTL RAISG Meeting Paris, 11 to 13 September 2013
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GNSS SiS disruption - Extent of risks
GNSS Policy: the vision for the use of a multi-constellation and multi-frequency GNSS in 2020+ This EUROCONTROL policy on GNSS is based on a gradual reliance on Satellite navigation that has as final goal its use as sole service, to the extent that this can be shown to be the most cost beneficial solution and if is supported by a successful safety and security analyses.
AMC 20-28 on NAVAID Infrastructure assumptions The acceptability of the risk of loss of LPV approach capability for multiple aircraft due to satellite failure or SBAS system failure, loss of availability of satellite signal or radiofrequency interference, will be considered by the ANSP providing the approach.
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Meaconing
GNSS SiS disruption - Extent of risks
Un-intentional RFI
Spoofing
Intentional RFI
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Counterfeit GNSS Signal
Delay & Rebroadcast
Current ATM systems for PBN OPS unprotected from injection of misleading GNSS information !
GNSS SiS disruption
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GNSS SiS disruption - Extent of risks
Excerpt from AIC A 21/12 FRANCE 4.4 Missed approach “Most of missed approach paths in France are RNAV procedures based on a level of performance at least compatible with the use of a GNSS ABAS receiver (of RAIM-reinforced GPS type).
Note: The availability of RAIM-reinforced GPS for missed approach is higher than the availability required for final approach. As a matter of fact, the accuracy of navigation required for missed approach is 1 NM for 95% of time vs. 0.3 NM for 95% of time for final approach. Therefore, RAIM availability forecasts obtained through NOTAM or tools specific to operators are not representative of missed approach availability. For similar reasons, a GNSS SBAS receiver may become unavailable for LPV minima, whereas its capability to follow the missed
approach has not been affected. The main event leading to a simultaneous loss of GNSS guidance during final approach and missed approach is interference due to jamming.
If the missed approach path is a RNAV procedure (not relying on conventional radio-navigation means):
The operator may have defined previously in their procedures, an emergency procedure for the case
where the loss of RNAV guidance during the approach does not allow to follow the missed approach procedure provided for the considered runway.”
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Example of safety risks associated with GNSS SiS degradation/loss for PBN OPS
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GNSS SiS disruption - Extent of risks
Several issues:
Are the LSAs covered risks of GNSS SiS disruption/denial for GNSS based PBN OPS already implemented?
What are current GNSS reversion modes for RNP operations where missed approach are GPS based?
Are the operators supposed to develop contingency procedures for operations in GNSS disrupted or denied environment?
How pilots / ATCOs / NAV system know if the GNSS SiS spoofing is undergoing?
etc.
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GNSS SiS disruption - Extent of risks
Current scheduled and non-intentional GNSS jamming threats:
DME/TACAN on L5/E5
GNSS repeaters
GNSS pseudolites
Higher harmonics and intermodulation products of various RF emitters
LightSquared GPS Interference (in USA)
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GNSS SiS disruption - Extent of risks
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Un-intentional RFI types & sources
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GNSS SiS disruption - Extent of risks
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Un-intentional RFI types & sources
Interference Type Telecommunication Systems GNSS Bands
Aeronautical Communication
Systems
DME
Galileo E5a E5b GPS L5
TACAN
Secondary Surveillance Radar (SSR)
Multifunction Information Distribution System (MIDS)
Joint Tactical Information Distribution System (JTDS)
TCAS
Identity Friend and Foe (IFF)
ADS-B
Radar Air Traffic Control radar Galileo E6
GPS L2 Solid State radar
Satellite Communication Systems Mobile Satellite Service (MSS) close to GPS L1
Secondary harmonics
TV Channels Galileo E1
GPS L1 Digital Video Broadcasting – Terrestrial (DVB-T)
Digital Audio Broadcasting (DAB)
Others
Personal Electronic Device (PED)
all VOR
ILS harmonics
Ultra Wide Band (UWB) Systems
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GNSS SiS disruption - Extent of risks
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Effects of jamming on unprotected GPS performance
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ECTL and ICAO activities on GNSS SiS disruption
ECTL
Navigation Steering Group (GNSS & Infrastructure Session)
ICAO
CNS SG
PBN/GNSS TF
ICAO EANPG (FMG)
Other groups
Aeronautical Spectrum Frequency Consultation Group (ASFCG)
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ECTL and ICAO activities on GNSS SiS disruption ICAO 12th Air Navigation Conference recommendations related to GNSS vulnerability
Recommendation 6/7 – Assistance to States in Mitigating Global Navigation Satellite System Vulnerabilities
ICAO to assess the need for, and feasibility of, an APNT system
Recommendation 6/8 – Planning for Mitigation of Global Navigation Satellite System Vulnerabilities
States to: Assess the likelihood and effects of GNSS vulnerabilities in their airspace and apply, as
necessary, recognized and available mitigation methods; Provide effective spectrum management and protection of GNSS frequencies to reduce the
likelihood of unintentional interference or degradation of GNSS performance; Report to ICAO cases of harmful interference to GNSS that may have an impact on
International Civil Aviation operations; Develop regulatory framework governing the use of GNSS repeaters, pseudolites, spoofers
and jammers; Support introduction on-board mitigation techniques, particularly INS Where terrestrial NAVAIDs are part of a mitigation strategy, give priority to retention of DME
in support of INS/DME or DME/DME area navigation, and of ILS at selected runways.
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Mitigation of GNSS SiS disruption
Passive measures
Multi Constellation /
Frequency GNSS
APNT system RFI Monitoring
Networks
Aircraft on-board IDLM
Real time RFI Detection & Localization
ECTL NSG currently coordinating development of GNSS RFI mitigation framework and action plan at ECAC level!
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Real time RFI Mitigation
Legal prosecution
GRF Spectrum
protection
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Mitigation of GNSS SiS disruption
APNT required capabilities
In TMA APNT should be able to provide RNP 0.3 to support NPA and to allow aircraft to get to the FAF of terrestrial based PA as an ILS.
Support for 3NM separations by providing 0.1NM position accuracy.
“Previous coverage and performance studies conducted show that current specified accuracy of DME must improve by about a factor of two to support RNP 0.3 in the areas studied. The accuracy has to be even better if separation standards need to be met.”
APNT – Alternative Position, Navigation & Timing
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Mitigation of GNSS SiS disruption
BAE Systems Small Antenna System Advantages:
Effective against large intentional
Disadvantages:
High cost and size
Jammer sources difficult to localize
Inefficient for multiple jammers
Adaptive Spatial Nulling Antenna/CRPA
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Assessment of the LightSquared Ancillary Terrestrial Component Radio Frequency Interference Impact on GNSS L1 Band Airborne Receiver Operations – RTCA Report to FAA Adaptive Spatial (Antenna) Processing
“… There are limitations to the number of interference sources that can be simultaneously suppressed. The FAA has dismissed the use of such technologies for civil aircraft since they are export-controlled, which combined with the above high costs makes this technology impractical for civil aviation.”
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Mitigation of GNSS SiS disruption NAVAID supporting GNSS reversions to RNP
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DME/DME/INS system
Currently not capable to support RNP specifications for APCH OPS and 3NM separations
APNT system
Under definition and development
The most promising DME/GBT (Ground Broadcast Transceiver – ADS-B) – modified system with use of signals of opportunity in DME band
Multilateration & Pseudolite alternatives
Signals for passive ranging: • DME based Passive Ranging (DMPR) • UAT Passive Ranging (by ADS-B GBT)
Potential signals for passive ranging: • Mode S on 1030/1090 MHz • VHF communications • Future Communication System (FCS)
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Mitigation of GNSS SiS disruption Other means of mitigation
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eLORAN Robust Position & Timing Capability as timing subsystem for APNT Multilateration & Pseudolite
Alternatives) Real-time differential corrections Corrections and integrity status via eLoran data channel
Supported application Prototype eLORAN eLORAN
Resilient PNT
Non-Precision APCH
Stratum 1 frequency
UTC
Precise timing
Interference detection & mitigation
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Objectives:
Maintaining and recovery of GNSS SiS integrity in intentional or un-intentional RFI environment
Real-time IDLM on-board the aircraft
Oriented on exploiting of aircraft FRPA-TSO antennas (instead of multi-antenna array/ CRPA; multiple TSO antennas)
Minimum alterations of CNS sub-systems (adding signal processing component in the line between antenna assembly and GNSS Rx)
GSINTA Project Gnss Sis INTegrity Assurance
“This research was supported by a Marie Curie IEF within the 7th European Community Framework Programme”
Supporters: Technische Universität Braunschweig – Institute of Flight Guidance
Septentrio nv
Host research institution: Royal Military Academy (Belgium) - CISS
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Methodology
RFI Data acquisition:
Laboratory OTA RFI measurements
Real world flight campaign measurements (controlled RFI by on-ground jammers)
RFI model building
IDLM solution development
IDLM solution testing:
Laboratory testing
Real world flight campaign validation
GSINTA Project Gnss Sis INTegrity Assurance
“This research was supported by a Marie Curie IEF within the 7th European Community Framework Programme”
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SPECTRUM ANALYZER
RFI SIGNAL GENERATOR
RFI ACQUISITION CONTROLLER
GNSS SIMULATOR
Horn Antenna Radiator
RHCP Antenna Radiator
GNSS RECEIVER
GNSS Antenna
TSO GNSS Antenna
GNSS Timing
RECEIVER
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GSINTA Project Gnss Sis INTegrity Assurance
“This research was supported by a Marie Curie IEF within the 7th European Community Framework Programme”
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SPECTRUM ANALYZER
ACQUISITION & CONTROL
TSO GNSS Rx #1
TSO GNSS Antenna #1
FGS
TSO GNSS Antenna #2
TSO GNSS Rx #2
SYNC SYSTEM GNSS Rx
TSO GNSS/VHF Combo Antenna
INS
GNSS Antenna
SYNC SYSTEM
SPECTRUM ANALYZER
RFI SIGNAL GENERATOR
RFI ACQUISITION CONTROLLER
Reference GNSS
RECEIVER
RFI Emitter Antenna
Isotropic Measurement Antenna
Real world flight campaign - controlled RFI from ground jammers
Initial data acquisition
Solution validation
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Types of interferers considered:
CWI
NBI
WBI
Pulsed CWI
Pulsed NBI
Pulsed WBI
Sweep-through
GSINTA Project Gnss Sis INTegrity Assurance
“This research was supported by a Marie Curie IEF within the 7th European Community Framework Programme”
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GNSS frequencies considered:
GPS L1/L2/L5
Galileo L1-E1-L2/E5/E6
GNSS signals/codes considered:
GPS C/A
GPS Y
Galileo CS
Galileo PRS
Galileo SOL
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Benefits:
Short term oriented potential on-board IDLM solution
Real-time IDL simultaneously by several aircrafts in TMA affected by RFI and reporting of interferer location to the service authorized to remove interferer
GSINTA Project Gnss Sis INTegrity Assurance
“This research was supported by a Marie Curie IEF within the 7th European Community Framework Programme”
Carrier-to-Noise Ratio (CNR) Degradation Baseline Test
Measurement Accuracy Test
SBAS Message Loss Tests
1st satellite loss threshold [dB]
3D navigation loss threshold [dB]
Reacquisition threshold [dB]
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RFI tests using MOPS-based GNSS receiver :
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Scenario A Spoofing or Meaconing of GNSS SiS for RNP APCH and DEP operations GNSS RNAV protected Missed Approach (IMC conditions at minima values for APCH; complex geographic environment)
SA with Scenarios of GNSS deteriorated/denied environment
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Scenario B Spoofing or Meaconing of GNSS SiS for ATSA-AIRB ADS service in IMC or ATSA-SURF service during LVOs
Examples of critical scenarios to consider in LSAs for PBN OPS implementation:
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Disruption or loss of GNSS SiS can result in several operational issues especially when reverting to same or lower RNP application:
Transitioning from 3NM to 5NM separation enroute and on arrivals outside of 40NM (DDI unable to assure 3NM separation);
Sudden increase in radar vectoring within airspace volume affected (in RA; number of ATCOs available);
Aircraft diverting to alternative APRTs (Contingency and Holding Fuel policy might not be covering such NAVAID related diversions);
At APRTs with Parallel Runway Operations sudden fall in capacity;
Load of TVs (impact on configurations and sector/TV capacities).
SA with Scenarios of GNSS deteriorated/denied environment
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Proposed steps forward
Consolidation of methodology, techniques and prospective developments in GNSS vulnerability mitigation – initiative by ECTL and ICAO WGs
Formally agree on APNT for the GNSS based PBN navigation applications
Recognizing areas of interest in current R&D to consolidate past and future efforts in SESAR projects supporting on-board IDLM and APNT
Need to consider re-evaluation of NAVAID infrastructure plans due to APNT
Include scenarios with GNSS SiS deteriorated /denied environment into future LSAs for GNSS based PBN navigation applications implementation (including re-application of LSA for past implementations where such scenarios were not considered)
MS to contribute to ECTL NSG lead in GNSS RFI mitigation framework and action plan at ECAC level
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General RFI Effects on Aeronautical GNSS Receivers Backup slide #1
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Example from USAF (source: USAF 746th Test Squadron)
Jamming event in Mesa, AZ
13-18 Dec 2001, GPS jammer caused GPS failures within 180NM of Mesa, AZ
Boeing was preparing for upcoming test
• Accidentally left jammer on L1 frequency radiating at 0.8mW
• Jammer operated continuously for 4.5 days
Impact to ATC operations
• A/C lost GPS 45NM from PHX, performed 35° turn toward traffic
• NOTAM was not issued until 2nd day
• Numerous pilots reported loss of GPS NAVAID