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1 INTRODUCTION
Reliable positioning is recognized as one of the
fundamental requirements for the safety at sea. For
almost 50 years after the WW2 hyperbolic systems
(Decca, Loran etc.) dominated in sea navigation.
HoweversincefirstNavySatelliteNavigationSystem
(Transit) this state gradually changed and now, for
many years
Global Navigation Satellite Systems are
recognized as the primary source in positioning. In
factweobserverealmonopolyofGPSinthisfield.
On the other hand we know that these systems
haveaweakresistanceonmanydisturbances[1].So
reliance on a single position source when its
vulnerability
is known, bring us to not acceptable
risk.Itisespeciallyessential when many devices on
theshiprequirepositioninputtoitswork.Thisisnot
only mariners’ problem, as today many crucial
aspectsofthesocietylifeisdomineeredbyGPS.This
statement refers not only to the navigation,
nevertheless in the general feeling the system is
treated as the element of the navigational
infrastructure. A lot of critical infrastructure
applications involving safety, security, and the
economic flow of goods is dependent from
Positioning,NavigationandTimingsystemsas well.
Let Us Prepare the Officer of the Watch on Jamming
and Spoofing
A.Felski
PolishNavalAcademy,Gdynia,Poland
ABSTRACT:ThegeneralaccessibilityandhighaccuracyofGPScausedthatforadozenorsoyearsitisapplied
commonly, not only in marine navigation. We can ascertain that in this regard there exists the monopoly.
However,nowitis apparentlythat thissystem can
beeasilydisturbed,whattestifynumerous reports. The
problem has been treated as troubles in land navigation, however nowadays became every‐day reality on
coastalwatersaswell,especiallyontheMediterraneanandBlackSeasandPersianGulf.
Officerswhosurvivedthistellthatthefirstimpulseinsuchsituation
istoverifyGPSreceiver,regardlessofthe
situationaroundtheship.Theconcentrationoftheofficer’sattentionontheGPSreceiver,especiallyoncoastal
waterscreatesthethreatfortheship,howeverinthissituationappearotherthreatswhichmanyofficersdoes
not associate with GPS. Usually on the present
ship GPS receiver is not only the source of positioning
information. It is a source of information for many other devices, so inappropriate work of it generates
problemswithmanyotherprocessesontheship.TodayquestioniswhoonthebridgecannoticeGPSproblems
andhow?Thereare
receiverswhichdonotinformabouttheproblem,orpresentnotrealisticdata.Sometimes
onlyECDISpictureshowssomeabnormality,forexamplestillthesamepositionwhileshipisundertheway.
On the paper the analysis of possibly aspects of the problem is discussed. Presented analysis goes to the
conclusion
thatshouldbepreparedsomeprocedurehowtoproceedincaseofthelackofGPSsignals,aswell
asthewatchofficershouldbepreparedtoactinsuchsituation.Thisisataskformarineacademies.
http://www.transnav.eu
the International Journal
on Marine Navigation
and Safety of Sea Transportation
Volume 13
Number 4
December 2019
DOI:10.12716/1001.13.04.18
848
Formanyapplications,likecellularphones,itsuseis
essentialandthemostofusersisfamiliarwithit.
The absolutely new perspective in this aspect
drawstoustheappearanceofunmannedships.From
theonesidewecannottoallow,thatunmannedship
willsailwithoutpositioningdata,
whenexperienced
man can manage this for some time. The second
aspect of this problem is possibility to capture the
unmannedshipbypirates,whatwasdemonstratedas
opportunity by Iranian forces against US Predator
drone in 2013 by means of manipulations with GPS
signals[10].
2 KINDSOFDISTURBANCES
ANDTHESCALE
OFTHEPROBLEM
GPSwasbuiltastheinterferenceproofthankstothe
useofthetechniqueofwidespectrum.Butalreadyin
the first half of 90‐these first report about the
possibilityofthedisturbanceofGPSsignalhasbeen
published [Falen, 1994]. Then possibilities of
interferenceswasforeseen.Asfarasin2001thereport
of the American Department of the Trade widely
analyses potential possibilities of the interference of
the signal GPS with broadband wireless
communicationsystems,thanin2011RoyalAcademy
of Engineering report [Global Navigation, 2011],
[Space Weather, 2013] as the greatest
threat attends
the problem of the intended perturbation of GPS
signal with portable devices. Today is clear, that
Space‐based PNT systems have many limitations,
amongwhich interference, jamming, meaconingand
spoofingarementionedasrealandmostessential.
Figure1. The most common “personal” jammers. Source:
[gpsworld.com].
The problem of anti‐GPS activity isn’t a new
threat.Therootsofthisandsimilartechnologiescan
befind in the WW2eraandlater, inColdWar. The
first attempts to produce some “radio‐noise” for
counteractagainstenemy radio transmission we can
observeduring theWWII.Later,attempt
to transmit
fakeradarechoestobuildfalsepictureontheenemy
radarscreen–inseventies.
Generally speaking there are three options to
disturb GPS signal in intentional mode: jamming,
meaconingandspoofing[Cameron,2014].
Ja mming seems to be the easiest method, as its
sense is to produce enough power of the radio
noiseinreceiver’sspectrum.Thisistruth,thatGPS
receiver works even below of the noise level,
howevertheSignaltoNoiseratioislimited.Ifthe
ratioofthenoiseis
overthelimitinspiteofallthe
receiverdoesnotreceivetheusefulsignal.
Meaconing means a manipulation in the time of
the delivery of satellite signals tothe receiver, in
fact‐introducingsomedelaytotheirpropagation.
Finally coordinates of the position will be
incorrectlycalculated,asthisprocessbasedonthe
timeofsignalpropagation.
Spoofing is the method of transmitting to the
receiver signals which seems to be GPS signals,
however there are produced out of the system –
not by satellites, but by enemy generator.
Reportedly for this the perfect means are GPS
simulators. The threat of spoofing for GPS was
discussed many
times by specialist, during open
discussed,aswellasprobablyintheclosedbodies.
For long time many specialist argued that in
realityspoofingis“toohard”toconductitinareal
conditions. Today many evidences show, that it
works.
Asjammingneedsimpledevices,nowadaysthisis
observed in
many areas and for different reason.
ComplaintsofScottishfishermenalmosttenyearsago
provethatNATOproducessuchdisturbances forits
ownexercises.Ontheotherhand,accordingtopublic
pronouncements of Prime Ministers of Finland and
Norway in February this year, after last NATO
exercises, Russia acts so
in case of exercises of pact
forces. Many experienced ship officers report such
evidences in the west part of Mediterranean Sea in
2017and2018.
For long time Spoofing has been treated as not
workable, up to 2013, when Psiaki with his team
demonstrate it in famous experiment on
Mediterranean Sea
[Psiaki, 2016]. In this experiment
the team from University of Texas (Radionavigation
Laboratory) were carried out an experiment where
GPS‐guided drone was fooled into “thinking” its
altitudewasincreasingandthiscausedittolowerthe
flight and finally – landing. In 2014 the same team
demonstratedhowyacht
couldbesteered off‐course
by means of spoofing attack. In this experiment
yacht’s GPS receiver was spoofed into “believing”
that it was veering off its course, set northwards to
Venice, and heading south to Libya at a very high
speed[Cameron,2014].
Figure2. Photo of GPS receiver on the spoofed yacht.
Reader should notice altitude of the yacht (minus 4000
meters)andspeed(449knots).Source:[Cameron,2014].
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In this context it is worthy to mention two facts
from the life of US Armed Forces. In 2011, Iran
announced that it had captured a highly classified
drone(Predator) belonging to the CIAbyfoolingits
GPS to make it land in Iran instead of Afghanistan.
Nextyeartwo
U.S.Navypatrolboatswanderedinto
Iranian waters. The Iranian military intercepted the
boat and captured 10 U.S. sailors. The seamen were
releasedthenextday,butnomilitaryofficialwasable
to explain why the boats equipped by well‐trained
military personnel had strayed from their intended
path.The
incidentpromptedspeculationthatIranhad
sentfalseGPSsignalstolurethesailorsontoanother
course,howeveritwouldnothavebeeneasyforthe
Iranians to hijack the military GPS receiver, as
military signals are heavily encrypted, contrary to
C/Asignals.Anywayaccidentisstillnotexplained.
Two
or three years later Pokemon Go, a new
mobile phone game appeared. Then in Moscow
youngpeoplediscovered somethingstrange, namely
thataroundtheKremlintheirsmartphonesstillshow
position on Wnukowo airport! They quickly
discoveredthataroundtheKremlinthreetransmitters
offalsesignalsaredistributed.
Figure3. Distribution of spoofers around the Kremlin.
Source:[TheKremlin,2016].
In summer 2018 widely was commented the
spoofing incident at Black Sea, near Novorossiysk.
Almost20shipssignaledatthesametimecompletely
false coordinates, presented by the GPS receiver,
causingimpressionofthestableworkofthereceiver.
ThearmedconflictinSyriahasbeenblamedformuch
of the
disruptions of its shores [Goward, 2018].
Similar evidences of jamming or spoofing has been
observed also in Jeddah, Haifa, Strait of Hormuz as
well.
The fact that the vast majority of marine GPS
receivers in the world relied solely on the
unencrypted C/A code became a cause for concern.
Especially
where biggest part of ships and many
waters can be treated as elements of critical
infrastructure.
Figure4.ExamplesofseriousincidentsinGPSdisruptions
in2018.Source:[Goward,2018].
3 SOLUTIONOFTHEPROBLEM
Manypeoplestillbelievedthatitistoohardtobuild
so complex equipment necessary to perform the
spoofingattack,andthisisoutofreachforpotential
terrorists. In fact, commonly accessible, low‐cost
software‐defined radio (SDR) enables spoofing if
couplewithopen‐source
GPSsimulationsoftware!In
thewebexistsdetailshowtoperformbasicspoofing,
andexampleshowtheyspoofedadrone.Thesemay
not be the most sophisticated setups, but it’s good
enoughtodothejobinmanycases.Thereisnodoubt
that many states use this tactics in
the everyday
practice. Regarding the possibility of the common
usageofjammingtherecannotbedoubts.
The treats of vulnerability of GNSS systems is
commonly criticized and equally criticized is
dependence on one source of information. In this
situation, for example in 2015, U.S. House of
Representatives in Resolution 1678 approved
a
resolution that would require establishment of a
“strong, difficult‐to‐disrupt terrestrial system to
complement GPS, and to serve as another source of
PNT when GPS isn’t available” [H.R.1678]. This has
been noticed not only in US, and has led many
institutionstolookforalternativesolutionsthatallow
an application to maintain the efficiencies and
effectivenessgainedfromthelossoftheirspace‐based
systems and augmentations. As well within the
framework of the e‐Navigation project necessary of
back‐up system is notified. In this situation it is
natural that at present a lot of international projects
are
executed inthisfield.Themostattractivein this
context seems to be AIS, DGPS and Loran
modernization.Thecommonbasisforthisoptionsare
well coordinated time stamps. According to the
opinionofsomespecialists[Barletetal.,2017],[Ward
etal.,2015]newversionofLoran(enhancedLoran,
e‐
Loran)isdeclaredbyUSofficialsandBritishGeneral
LighthouseAuthority(GLA) asthemostperspective
system and from this reason some money are
intended for development works. Similar works are
drivenalso inSouthKorea.Atthemoment e‐Loran,
which was introduced by American company Ursa
Navin
themid‐1990sseemstobeclosetorealization.
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ButNederland’sproposalEurofixisinvestigatedtoo,
and this solution was installed already in the
beginningofXXIcenturyinSaudiArabia[Cameron,
2015]. However at the moment, and probably for
some next years this is still a future. The matter of
consequence is the scale of introduction of such
solutions worldwide, because we remember that
radio‐navigation systems never existed neither in
SouthAmerica,norinAfrica.
4 CONSEQUENCESOFTHEPROBLEMSWITH
GPSANDSUGGESTIOINS
From examples mentioned above we must draw a
conclusionthatdifficultieswiththeutilizationof the
GPSbecomeacommonplaceness.Theunstablework,
falsesignalsortheinaccessibilityoftheGPSbecomea
problem of our life. So today the practical question
appears:howtheofficerofthewatchshouldbehave
in such situation? How many officers are ready to
recognize[Felski,2016]presenceofjamming?Iheard
many tales of persons who had
such adventures on
the bridge. Almost all they tell that in the first
moment they began to analyze reasons of the faulty
operation of the GPS receiver, and in that time the
ship began to change course. What happened? The
answer is simple: the autopilot received data about
thebearing
tonextwaypoint(WPT) andtreatedthis
as new Course Over Ground (COG), however
incorrect GPS fix caused the wrong information,
whichisnotrecognizedbyautopilotasincorrect.
Similar, unforeseeable events, especially in the
Integrated Navigational Bridge (IBS) or Integrated
Navigation System (INS) can happen [Barlet et al.,
2017].There
aredifferencesbetweenIBSandINS,but
for this analysis let’s skip them. So IBS (or INS) is
commonly defined as sets of mutually joint sensors
and executive elements which make possible the
access to the information and the steering by ship
from one workstation. What is crucial here is
the
phraseʺmutually jointʺ that means the complicated
dataflowandthemutualinfluenceofoneelementon
thesecondone.
Inthatcase watchofficershouldbefamiliarwith
processes of the dataflow among the receiver GPS,
withtheautomaticpilot,ECDIS,ARPA,AIS,aswell
as with the gyrocompass and
log. Essential for
analysis of possibly consequences of disturbances in
GPS work isthe sentence of SOLAS Chapter V, Reg
19,para6“Integratedbridgesystemsshallbesoarranged
thatfailureofonesub‐systemisbroughttotheimmediate
attentionoftheofficerinchargeofthenavigational
watch
byaudibleandvisualalarms,anddoesnotcausefailureto
any other sub‐system. In case of failure in one part of an
integrated navigational system, it shall be possible to
operateeachotherindividualitemofequipment orpartof
the system separately” [SOLAS]. In such situation the
watchkeeperwillbeconcernedwithcancellingofall
alarms firstly, that the uneasy captain will come on
thebridge.Howevertheproblemisnotinalarms,but
inthereasonwhyalarmsareactivated!Thisseemsto
beself‐evidentandsimplethat[Roper,2017]:
Watchkeepersmustbefamiliarwiththeoperation
ofIBS(orINS)andinparticularmustbefamiliar
withthealarmsand be abletooperate anyover‐
ridearrangementsincaseofasystemfailure;
If a sub‐system of an INS fails the watch keeper
shouldbeabletooperatealltheothercomponents
ofthesystemindependently.
Unfortunately life is more complicated, and in
practicenotallofficersareefficientinthismatters.Of
coursewatchkeepersmustbe knowledgeable in the
configuration
ofthesystemandtrainedinperforming
thisindividually.Thisisthefact,thatevenonsister’s
shiptheconfigurationofthesystemcanbedifferent,
becausein thepa st somepersonchanged something
accordingto personal fancy. Easy suggestion is, that
clearly written instruction for the systems must be
available
onthebridge.
Themostvitalquestionistospecifydeviceswhich
receivedatafromGPSreceiverandtomakesurethat
backupsystemworks.Aspositioningsystemonbusy
waters the radar can be indicated as an attractive
backup option for GNSS. This is obligatory
equipmentontheboard,
andusuallystaysinuse,but
paradoxically, when ECDIS is in use, many officers
haveaproblemtotransferthepositionfromradarto
ECDIS.
Pleaseremember,thatnowadaysshiphasalotof
deviceswhichshouldbesupportedbyadditionaldata
and what in the past was performed by different
devices,notGPS.OneoflessassociatedwithGPSis
gyrocompasswhichoftentakesthelatitudeandspeed
forthecalculationofthespeedcorrection.
This is trivial and universally well‐known, that
situational awareness to include verified position, is
vitalforsafenavigation.Sonomatterhowgoodand
reliableisGPS,watchkeepersshouldusealternative
methodsandsystemsforcrosscheckingdatafromthe
system.Thisisanimportantrule,notonlyintheface
of GPS disruptions. Still manual checks and other
back‐upmethodsforpositioningmustbeexercisedon
aregularbasis.
Thesecondthreatis
inARPA.Theproperworkof
thisdeviceneedsdataabouttheheadingandspeedof
the ship. Today this can be transmitted as SOG and
COG from GPS receiver. So when GPS is disrupted
some problems with ARPA will occur either. It is
truth, that SOLAS requires speed and
distance
measuring devices which should be connected with
ARPA. However this device must work at the
momentandbeconnectedwithARPA.Isitsoevery
time?Bytheway,somecompanyofferstodaysatellite
speedometer which is in fact GPS receiver showing
only the speed, but in some level vulnerable
as
standardreceiver…
Insuchcircumstancesanexperiencedmastermay
suggesttousetheParallelIndexingmethodofwork
with radar. This is very efficient tool when
approaching the coast to confirm position or
determine turning waypoints [Bole et al., 2014] but
how many watch keepers are ready to use
so old
technique? Different investigations into cases where
vessels have run aground have often shown that,
whenradarwasbeingusedasan aid to navigation,
inadequate monitoring of the ship’s position was a
contributoryfactor.ParallelIndextechniquesprovide
the means of continuously monitoring a vessel’s
positioninrelationto
apre‐determinedpassagepla n,
851
notcheckingwhetherGPSworksornot.Itisproper
to instruct practicing this in clear weather during
straightforward passages, so that watch‐keepers
remain thoroughly familiar with the technique and
confidentinitsuseinmoredemandingsituations.
5 CONCLUSIONS
InthistextItrytopayattentionof
thereadersonthe
importance of disrupters in GPS accessibility and
correct preparation of officers of the watch in this
context. Over the recent years the problem of
intentionaldisturbancesinGPSworkgrows,andthe
awareness of unforeseeable results of this becomes
unusually important. Such threat extorts the
preparation
oftheofficeronthebridgetoevaluating
ofthecomplication,whichcanbecausedbythelack
ofGPSsignals.
Thus one can propose, that training scheme will
takeintoaccountsuchaspectsas:
Understanding the mechanism of jamming and
spoofing;
The skill to diagnose of jamming or spoofing
symptoms;
Efficient setting‐up and reconfiguring of the
integratednavigationsystem;
But also he should be competent in radar use in
themanner which is archaic in the opinion of many
youngwatchkeepers.
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