Ministère de l‘Environnement, de l’Énergie et la Mer

Direction générale de l’Aviation civile

Review of 20 years of Space

Weather impacts on Aviation

Aviation and Space Weather Forum 17 March 2016 – DGAC, Paris

Benoit Roturier

DSNA

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• Impact over Communication systems

• Impact over Navigation systems

• Impact over Surveillance systems

• Impact over Aircraft systems

• Unseen during the last 20 years , but…

PLAN

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• HF long distances Communications– Reflexion over the ionosphere, highly dependant upon solar activity

– Low/Mid latitudes vs. Polar regions

– Appropriate frequencies may vary, as well as blockage durations

• VHF short distances Communications– No significant impact reported

• Satellite communications― Mainly impacted by signal scintillation

― In the equatorial region severe scintillations can cause degradation and blackout

― At middle latitudes, impact seen during very strong space weather storms as occurred in October – November of 2003

― Attenuation: aviation data transmitted through a store-forward mode, no significant impact reported from Cayenne and Tahiti FIRs

IMPACT OVER COMMUNICATION SYSTEMS

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• Use of Australian predictions within Tahiti FIR

IMPACT OVER HF COMMUNICATIONS

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GNSS

GPS

GLONASS

Ground Based Augmentation System

(GBAS)

Aircraft Based Augmentation System

(ABAS)

GalileoGeostationary Satellite

WAAS EGNOS

Based Augmentation System

(SBAS)

MSAS GAGAN

SDCM

BeidouEGNOS

Satellite Based

THE CIVIL AVIATION GNSS

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• GPS, GLONASS, Galileo, Beidou– Ionosphere disturbs radiowave propagation

– Error on the user/satellite estimated distance

– Scintillation fades out signals

– Electromagnetic energy transmitted by the sun mayblackout signals– In December 2006, the Sun radiated very strongly at L1 and

L2 frequencies during a flare. – This burst caused codeless or semi-codeless positioning

techniques receivers on the dayside to lose lock for up to 10 minutes

IMPACT OVER GNSS

CORE CONSTELLATIONS SIGNALS

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• ABAS systems and operations

– Mainly based over core constellation signals

– Few operational limitations are observed since the tolerances are quite high for ABAS operations (lateral navigation only, error < 0.3 Nm)

• Next generation Dual Frequency Multi Constellation – Error on the user/satellite estimated distance eliminated

– Scintillation impact reduced due to a higher number of satellites

– More vulnerable codeless or semi-codeless receivers no more needed

IMPACT OVER GNSS ABAS SYSTEMS

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• Core constellation ionospheric errors/scintillation– Are today the main driver in term of system performance and

architecture

– Must be resolved, or the system must be automatically desactivatedover the impacted area

– Concerns/difficulties over areas around the geomagnetic equator

• DFMC GNSS will significantly improve the robustness/worldwide coverage

• The GEO communication link may also be impacted– WAAS Galaxy 15 GEO disrupted in 2010 due to fast solar winds

creating electrostatic discharge

– Mitigated (except Alaska North-West) since SBAS usually work with 2 or 3 GEOs

IMPACT OVER GNSS SBAS SYSTEMS

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STORM IMPACT OVER 3 SBAS SYSTEMS

EGNOS (EUR), WAAS(US), GAGAN (INDIA)

(From CNES)

• Shows the auto-adaptativemodification of coverage area of SBAS – Due to the wide scale

observation and internalmodelisation of ionosphere

• Strong perturbations of coverage area is however a rare event– ESSP may send warnings

to ANSPs

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• GBAS for Category I approach & landing operations– Ionospheric propagation of GPS signals impacted

– Unlike SBAS, since GBAS is a local system, there is a lack of observation of local disturbances which might create wrong positioning

– Operations limited today in the proximity of geomagneticequator (Japan, Brazil, Africa,…)

• GBAS for Category II/III approach& landing operations– ICAO standardisation delayed due to ionosphere impact

– The Cat II/III standard to be approved end of this year will not be usable in all ICAO States

• Next generation Dual Frequency Multi Constellation GNSS should also resolve these issues

IMPACT OVER GNSS GBAS SYSTEMS

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• Secondary Radars mode A/C– 04/11/15 @ 1430 Multiple Radar site failures initially in Malmo ACC and

Stockholm ACC followed at 1445.– Initial ACC global ‘0’ rate regulations applied for 2 hours

– Belgocontrol is investigating some alarms, which happened on 04/11/2015 on two of its older A/C radars

– Germany DFS observed a high number of false plots on 4/11/15.– But having modified their reply processor/correlator sw after an occurrence in the late

90´s they haven’t had any operational constraints anymore

– No impact reported over modern mode S radars, nor in France

• Automatic Dependant Surveillance systems– Ground ADS-Broadcast, Satellite ADS-Broadcast, ADS-Contract technologies do

all rely over GNSS positioning– vulnerabilities are thus connected to GNSS section discussion, and imply a common

mode of failure

IMPACT OVER SURVEILLANCE SYSTEMS

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• Electronic components are susceptible to impact• From the highly ionizing interactions of cosmic rays, solar particles and the

secondary particles generated in the atmosphere.

• Single Event Effects (SEE)• Upset the state of one (or more) bits

• Certain devices could also be triggered to burn-out and hardware failure;

• In-flight aircraft measurements of 4Mb Static RAM produced a rate of 1 upset per 200 flight hours

• Aviation industry has catalogued such events on equipment: • Auto-pilots tripping out and flight instrument units latching into built-in tests.

• Expected to increase as more low-power, small feature size electronics are deployed in “more electric” aircraft.

• Avionic manufacturers have to demonstrate how SEE, and failures, can meet high level certification requirements at equipment and system level

IMPACT OVER AIRCRAFT SYSTEMS

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IMPACT OVER AIRCRAFT SYSTEMS

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• 23 July 2012, just missed the earth:– By 6 days, with intensity similar to 1859 Carrington event

• Hit the earth, well before aviation: – Analysis of isotopic composition of ice layers in Groenland shows up to 5 times

more powerful solar events than 1859 Carrigton

• Theoretical studies show that, although very rare: ‒ 100 to 10 000 times more powerful than Carrington events are possible

‒ satellite destructive events are possible

‒ and resilience of ground systems, in particular electric transformers seriously challenged

• Potentially very high level of disruption over our society:– Aviation needs to better understand the degree of impact of such rare events:

– Understand the vulnerability of space infrastructure

– Better prepare the crisis management (see session 3)

UNSEEN DURING THE LAST 20 YEARS,

BUT…

Ministère de l‘Environnement, de l’Énergie et la Mer

Direction Générale de l’Aviation CivileFrom the UK report « Space Weather Preparedness Strategy » - July 2015

CONCLUSIONMAIN PHYSICAL EFFECTS AND THEIR IMPACT