183
1 INTRODUCTION
While the industrial revolution brought an
unprecedentedrevolutioninmaterialwealthtomany
nationsinthe19
th
and20
th
centuries,theturnof the
21
st
centurysawtechnologyenablingthecreationofa
virtual global village. The internet and increase in
computational speed increased the pace of
individuals’ lives, accelerated change and brought
nearlyeverypointoftheglobemuchclosertogether
in virtual space. Satellite navigation systems
augmented this by both providing an enabling
precise, synchronized ti
ming capability, and by
making it much easier to overcome physical spaces
thatstillseparatedindividualsandsocieties.
Thedawnofsatellitenavigationdatesto1958,and
the TRANSIT system created by the Johns Hopkins
University Applied Physics Laboratory, USA.
TRANSIT was used by naval vessels for navigation,
and as a surveying aid and frequency reference.
While there were some limit
ed civilian uses, the
inflection point for the technical revolution was not
reached until NAVSTAR GPS became fully
operationalonJuly17,1995.Sincethenithasbecome
asilentutilitysupportingeverythingfromelectronic
banking to cellular telephone systems and electrical
grids – not to mention tra
nsportation. Few can
imagine life without these and other services. Many
havebecomenecessitiesasthesystemsandmethods
theyreplacedarenolongeravailable.
LaunchofthefirstNAVSTARGPSsatellitein1978
beganthisnewtechnologicalera.Itwasfollowedby
the first launches of GLONASS (Russia) in 1982,
GALILEO(Europe)in2005,QZSS(Japan‐regional)in
2010, IRNSS (India‐regional) in 2013, and Bei Dou
(China)in2015.
Global Navigation Satellite Systems
–
Perspectives on
Development and Threats to System Operation
K.Czaplewski
GdyniaMaritimeUniversity,Gdynia,Poland
ResilientNavigationandTimingFoundation,USA
D.Goward
ResilientNavigationandTimingFoundation,USA
ABSTRACT:Therapiddevelopmento
f
satellitenavigationandtimingtechnologiesandthebroadavailability
ofuserequipmentandapplicationshasdramaticallychangedtheworldoverthelast20years.Ittook38years
fromthelaunchoftheworld’sfirstartificialsatellite,Sputnik1,(October4,1957)tothedayNAVSTARGPS
becamefullyoperational(July17,1995).Inthenext20yearsuserequipmentbeca
mewidelyavailableatthe
consumer level, and 10 global and regional satellite systems were partially or fully deployed. These highly
precise signals provided free to the user have been incorporated by clever engineers into virtually every
technology.Atthesameti
meinterferencewiththesesignals(spoofingandjamming)havebecomeasignificant
daytodayprobleminmanysocietiesandposeasignificantthreattocriticalinfrastructure. Thispaperprovides
informationonthecurrentstatusanddevelopmentofnavigationsatellitesystemsbasedondataprovidedby
thesystemsʹadministrators.Italsoprovidesinformat
iononLoran/eLoran,asystemwhichmanynationshave
selectedasacomplementandbackupforsatellitenavigationsystems.
http://www.transnav.eu
the International Journal
on Marine Navigation
and Safety of Sea Transportation
Volume 10
Number 2
June 2016
DOI:10.12716/1001.10.02.01
184
The first retail consumer GPS receivers, the
MagellanGPSNAV1000,wereshippedin1989.With
an increasing number of satellites and the
proliferation of receivers, the idea of regarding all
satellite navigation systems holistically was born. In
1994 the European Commission, European Space
AgencyandEurocontrolproposedcreatingthe
Global
Navigation Satellite System (GNSS). European talks
withtheU.S.governmentthattookplacefrom1995–
1999resultedinanofficialagreementoncooperation
and Europe’s continental EGNOS augmentation
system was established. Originally, “GNSS” was
intended to be an EGNOS complemented
combination of GPS and GLONASS. With the
emergenceofthe
GalileoandBeiDousystems,GNSS
hascometomeanallthesystemsgenerally.Moreand
more frequently receivers are configured to access
and use any and all navigation satellite systems
available.AsProfessorDavidLasthaspointedout,
the national systems have become interchangeable
andinvisibletotheuser.
GNSShasbecomeasystem
ofsystems.
Butasystemofsystemstillrequiresitscomponent
parts to function properly for users to access the
servicestheyneed.Thefollowingparagraphsdescribe
the operational and construction status of national
satellitesystems thatare most frequently referredto
in the context of
the Global Navigation Satellite
System.Theinformationpresentedhasbeenupdated
frominformationobtainedbynationalauthorities,at
the 15
th
IAIN World Congress held in Prague in
October2015,and at the 10
th
AnnualMeeting of the
International Committee on Global Navigation
Satellite Systems held inBoulder, CO, in November
2015.
Becausethesesystemsaresoimportanttovirtually
everyfacetofdailylifeintechnologicalsocieties,itis
also important to understand their vulnerabilities,
threatsagainstthem,andmitigationmeasures.Sucha
discussionisincludedafterthesystemdescriptions.
While readers of this paper may be primarily
interested in the positioning and navigation
propertiesofGNSS,itisessentialtorecognizethatthe
mostimportantandbroa dest useofGNSSsignals is
forhighlypreciseandsynchronizedtime.Thetiming
function supports IT
networks, telecommunications,
broadcast, financial, transportation, and energy
industries. Professor Brad Parkinson of Stanford
University, widely acknowledged as the “father of
GPS”assaidthatthesystemshouldmoreproperlybe
renamed Global Positioning and timing Services
(GPtS)[Parkinson2012].
2 NAVIGATIONSIGNALTIMINGAND
RANGINGGLOBALPOSITIONINGSYSTEM
(NAVSTARGPS)
ThesystemcommonlyknownasGPSwascreatedfor
theU.S.ArmedForces.Workaimedatdevelopinga
system began in 1960 when Dr. Ivan Getting, was
elected the President of Aerospace Corporation.In
1973, Air Force Major Bradford Parkinson and his
small group of engineers took over from
earlier
researchersandcreatedthefinalsystemconceptthat
was subsequently launched in 1978. The system
achievedfull operationalcapabilityonJuly17, 1995.
Currently the GPS system is utilized by more than
onetrillionofusersandtransmits4civiliansignals:
L1C/A‐thelegacysignal;
L2C‐
thesecondcivilian‐usesignal;
L5‐aviationsafetyoflifesignal;
L1C‐internationalsignal
Also, the GPS satellites transmit signals for the
militaryuse.
Presently, the system constellation consists of 31
satellites.Table1presentsadetailedlistofblocksof
currentlyoperationalsatellites.
Table1. Current GPS constellation‐status at 10 January,
2015[Brennan2015]
_______________________________________________
Satellite Quantity Average AgeoftheOldest
BlockAgeSatellite
_______________________________________________
GPSIIA 2 23.424.8
GPSIIR 12 13.718.2
GPSIIR‐M 7 8.210.0
GPSIIF 10 2.15.3
Total31 9.324.8
_______________________________________________
Itmustbenotedthatthesystemconstellationhas
been intensely rejuvenated throughout its life. For
example,5BlockIIFsatellitesweredeployedin2015.
From the year 2016 the constellation will be
supplementedby newgenerationsatellites.TheGPS
BlockIIIsatelliteswilltransmit4civilian‐usesignals:
L1 C/A,
L1C, L2C, L5 and 4 military‐use signals:
L1/L2 P(Y), L1/L2M. The first GPS III satellite is
planned to be launched in August 2016 [Brennan
2015].
Thecurrentlyactivegroundsegmentofthesystem
ispresentedinFig.1.
Figure1.ThegroundsegmentoftheGPSsystem[Brennan
2015]
Presently, the NavSTaR GPSsystem provides for
better accuracythan the published system standard.
Theaccuracylevelsaredifferentforthecivilianusers
(Fig.2)andmilitaryusers(Fig.3).
185
Figure2. Standard Positioning Service (SPS) for civilian
users[Whitney2015]
Figure3. Standard Positioning Service (SPS) for military
users[Whitney2015]
3 WIDEAREAAUGMENTATIONSYSTEM
(WAAS)
TheregionalWAAS systemwasjointlydevelopedby
theUSDepartmentofTransportationandtheFederal
Aviation Administration as part of the Federal
Radionavigation Plan augmenting the GPS system
operation. First activated in 1994 in North America,
the system was to ensure the use of
high accuracy
satellite navigation for aircrafts during taking‐offs
and landings (comparable with ILS category1). Not
until WAAS was introduced, could GPS be used in
aviation.Theionosphericdisturbances,clock drift,and
satelliteorbiterrorsmadetheGPSsignalnotaccurate
enough to meet the requirements for a precision
approach.
The ground segment of the system consists of
[Januszewski2010]:
a network of 38 ground ‐based reference WRS
stations receiving signals from the GPS system
satellites; after preliminary data processing the
measurements are transmittedto master stations:
20WRSstationsarelocatedinthecontinentalU.S.
(Albuquerque, Auburn, Aurora,
Billings,
Farmington, Fort Worth, Fremont, Hampton,
Hilliard,Houston,Leesburg,Longmont,Memphis,
Miami, Nashua, Oberlin, Olathe, Palmdate,
Ronkonkoma, Salt Lake City), 7 in Alaska
(Anchorage,Barrow, Bethel, ColdBay,Fairbanks,
Juneau, Kotzebue) 1 in Hawaii (Honolulu), 1 in
Puerto Rico (San Juan), 5 in Mexico (Merida,
Mexico City, Puerto Vallarta, San Jose
del Cabo,
Tapachula), 4 in Canada (Gander, Goose Bay,
Iqaluit, Winnipeg); another 9 will be built in the
future;
3 WMS master stations processing data and
determining the correction values in Hampton
(Georgia), Leesburg (Virginia) and Palmdole
(California);
two pairs of GUS stations transmitting the
correction messages to
geostationary satellites at
frequency of 6455.42 MHz located in Napa
(California), Littleleton (Colorado) and Brewster
(Washington), Woodbine (Massachusetts),
respectively.
Currently, the WAAS system uses two
geostationarysatellitestosendcorrectionmessagesto
GPS receivers, augmenting the horizontal position
accuracy provided by GPS to 2‐3 m. The systemʹs
coverageis
plannedtoencompassbothAmericas.The
planneddevelopmentwillinvolvetheoperationof4
geostationarysatellites(Fig.4)
Figure4. The planned coverage of WAAS geostationary
satellites[Lawrence2015]
4 GLOBALNAVIGATIONSATELLITESYSTEM
(GLONASS)
The development of Russian GLONASS
(GLObalnaya NAvigatsionnaya Sputnikovaya
Sistema) satellite system began in 1976 when the
Soviet Unionʹs governmental program was initiated.
Since the first GLONASS satellite was launched on
October 12, 1982, the system has competed with its
Americancounterpart.
The system configuration was complete for the
firsttimein1995.However,duetoashortlifespanof
satellites,structuralchangesintheSovietUnionand
insufficientfundingintheperiodfrom1995to2001,
thesystemconstellationwas reducedto7satellites.In
2001, the revitalization and modernization program
was
started, which resulted in fast development of
constellation.Currently,itiscomposedof28satellites
(TableNo.2).
186
TableNo.2.GLONASSconstellation‐statusatOctober2,
2015[Karutin2015]
_______________________________________________
SateliteBlockQuantity
_______________________________________________
Glonass‐M26
Glonass‐K2
_______________________________________________
Total 28
_______________________________________________
The signals transmitted by individual satellite
blocks[Januszewski2010]areasfollows:
forBlockIIM‐L1/L2(C/A);
forBlockIIK‐L1/L2(P),L3withCDMA.
The ground segment [Januszewski 2010] consists
of:
1SystemControlCenter(SCC)
6MonitoringStations(MS);
4UpLinkStations
(ULC);
4 Telemetry, Tracking & Command Stations
(TT&C);
2CentralClockStations(CC);
1SatelliteLaserRangingStations(SLR).
Currently,theGLONASS systemprovidesservice
withaccuracyof2.8m.
Figure5. The overview of GLONASSpositioningerrorsin
years2006‐2011[Mirgorodskaya2012]
9 rockets carrying Glonass‐M satellites will be
launchedintheyears2015‐2016.Theobjectivesofthe
upgradescheduledfor2012‐2020include:
satellitelifespanextension;
extensionofserviceprovidedbythesystem;
increaseofsatelliteclockstability;
introductionofSARservice;
addition of new
signals to the modernized
Glonass‐Ksatellites:L1OC/L1SC,L2OC/L2SC.
The upgrade isexpected to ensure 4 times better
accuracyowingto[Karutin2015]:
theintroductionofanewCDMAsignal;
theupgradeoftheground‐basedcontrolsegment;
the introduction of new atomic frequency
standards(2CAFs
+2RAFs);
the introduction of advanced satellite, orbit and
clockcontrolsystem;
the change ofthe geodeticreference systemfrom
the presently used PZ‐90 system to PZ‐90.11
aligned to the International Terrestrial Reference
Frame(ITRF)atthemillimeterlevel.
thesynchronizationof GLONASStimewith
UTC
(SU) at less than 2ns while keeping long‐term
stability.
Figure5. New CDMA Signals Implementation Plan
[Revnivykh2015]
5 BEIDOUNAVIGATIONSATELLITESYSTEM
(BEIDOU)
ThefirstsatelliteoftheChinesesatellitesystem was
placed in geostationary orbit on October 30, 2000.
Once the full operational capability is achieved, the
constellation will be composed of 5 geostationary
satellites(GEO),3satellitesingeosynchronousorbits
(IGSO) and 27 satellites in medium
Earth orbits
(MEO).The systemisdesignedasa regional system
covering the area of the Peopleʹs Republic of China
andapartofSouth‐EastAsia.
Figure6.BeiDoucoveragearea[CSNO2013]
Currently,BeiDouiscomposedof:
5 geostationary satellites (positioned at
58.75°E,
80°E,110.5°E,140°Eand160°E)
;
20IGSOandMEOsatellites.
From March to September 2015 4 satellites were
deployed. If the pace at which new satellites are
activatedismaintained,thesystemwillbecomefully
operationalin2017asplanned.
Thesystemaccuracyisbetterthan10m.
187
Figure7.BeiDousystemʹsaccuracy[Ran2015]
BeiDougroundsegmentconsistsof:
MasterControlStations(MCS)
UplinkStations(US)
MonitoringStations(MS)
Figure8.ThecurrentconstellationofGALILEO[Hein2015]
6 THEEUROPEANNAVIGATIONSYSTEM
(GALILEO)
Inthe80ʹsofthe20
th
centuryaneedfordevelopinga
Europeansatellitesystememerged.Intheyears1999–
2000 technical and economic requirements of the
projectwerespecified.InDecember2004,thetesting
of GALILEO ground segment was complete and on
December 28, 2005 the first GIOVE‐A satellite was
placedinorbit.Theconstellation
statusasatOctober
15,2015ispresentedinFigure8.
The initial problems with the system activation
were overcome. The production, testing and
activationofthefollowingsatellitesareproceedingas
planned. Currently, the system has 12 in‐orbit
satellites.Thefactthattheirnumberdoubledin2015
is
impressive. Soyuz rocket launched in French
Guiana insertedthe 11
th
and 12
th
GALILEO satellites
intoorbitonFebruary2,2016.
The systemʹs ground segment is complete. The
visualizationofdeploymentofthegroundsegmentis
presentedbelow.
Figure9.TheGalileogroundsegment[Jean2015]
According to the estimations of the European
Union, the system will have achieved its full
operationalcapabilityby2020.ThreeAriane5 rockets
areduetobelaunchedinthesecondhalfoftheyear
2016,eachcarrying4satellites.Satellitesareproduced
in OHBʹs plant in Bremen, Germany. The
systemʹs
activation is co‐financed by the European Space
AgencyandtheEuropeanCommission.
7 EUROPEANGEOSTATIONARYNAVIGATION
OVERLAYSERVICE(EGNOS)
The development of the European Geostationary
NavigationOverlayServicewasfinishedin2006.Itis
aEuropeansystemaugmentingGPS and GLONASS
systems.AfterGALILEOisinitiated,EGNOS
willalso
supplementthisEuropeansystem.Thespacesegment
is composed of 3 geostationary satellites providing
coverage to all European countries. The ground
segment comprises 40 reference and retransmission
stations as well as 6 control and control‐verification
stations:
34 Ranging and Integrity Monitoring Stations
(RIMS): receiving navigation signals from
GPS
satellites,
188
6NavigationLandEarthStation(NLES):sending
correctionmessagestosatellitestoallowend‐user
devicestoreceivethem,
4MissionControlCenter (MCC):processingdata
andcountingdifferentialcorrections,
2 control and verification stations: DVP
(Development Verification Platform) and ASQF
(ApplicationSpecificQualificationFacility).
Figure10.EGNOSarchitecture[Jean2015]
EGNOSprovidesthreeservicesshowninTable3.
Table3.ServiceprovidedbyEGNOS[Jean2015]
_______________________________________________
ServiceAccuracyServiceStatus
_______________________________________________
OpenService about1m,Availablesince
freeaccessOctober2009
SafetyofLife About1m,compliant Availablesince
Servicetoaviationstandards March2011
EGNOSData Lessthan1m,AvailableSince
AccessService correctionsare 2012
providedby
terrestrialnetworks
_______________________________________________
TheEuropeanCommissionhasadoptedprojectsto
furtherdevelopthesysteminthefollowingyears.The
projects arepartially being performed. EGNOS is to
provide service to the territory of 28 EU member
states.Also,theworksonthethirdversionofEGNOS
system capable of sending messages in dual
frequency
(L1/L5)willhavebeenfinishedbytheend
of 2016. The following version will provide
augmentation to GALILEO and other systems to be
initiated as part of GNSS in the future. The third
version is scheduled to be launched in 2017. In the
yearstofollow,EGNOSʹs
coveragemaybeextended
on other European countries (other than EU
countries) and African countries provided all the
requiredinternationalagreementsareconcluded.
8 QUASI‐ZENITHSATELLITESYSTEM(QZSS)
The government of Japan approved the project to
builditsownsatellitesystemin2002.Theconceptof
the system is different
from the systems described
above.ItwasproposedthatthreeQZSSsatellitesare
to be placed in the so called quasi‐zenith orbit. The
plannedserviceareaofthesystemispresentedinFig.
11.
Figure11.QZSSʹsservicearea[Moriyama2015]
The parameters of the orbit have been chosen so
that at least one of the satellites is always almost
directly overhead above the Japanese islands. This
willprovidebettercorrectionsignalavailabilityeven
in Japanese cities crowded with skyscrapers. The
accuracyofthesystemisexpectedtobebetterthan1
‐
2minJapan.
Figure12.TheplannedaccuracyofQZSS[Kogure2015]
ThefirstMICHIBKIsatellitewasplacedinorbitin
2010. The system constellation is to comprise 4
satellites: 3 QZSS satellites 1 geostationary satellite
(127°E). The system will be further developed to
include 7 satellites around the year 2023. The
scheduled commissioning of subsequent satellites is
presentedinFig.13.
Figure13.QZSScommissioningschedule[Moriyama2015]
Thegroundsegmentofthesystemiscomposedof:
2MasterControlStations
189
7SatelliteControlStations
Over 30 Monitor Stations around the world
(includingexclusiveGPSmonitoringusestations)
Acompletegroundstationwillbegintooperatein
2018.
The Japanese space agency assumes that the
SatelliteBasedAugmentationSystemwillbeavailable
to QZSS in 2020. The frequencies available
in the
systemareshowninTable4.
Table4.ListoffrequenciesinQZSS[Moriyama2015]
9 MULTI‐FUNCTIONALSATELLITE
AUGMENTATIONSYSTEMMSAS
The Japanese MSAS augmentation system started
operatingin2007.Itprovides servicetotheterritory
of Japan. It is not a typical system, when compared
with WAAS and EGNOS, as the space segment is
composed of two geostationary meteorological
satellites (140°E and 145°E),
whilst other systems of
this kind use commercial telecommunication
satellites. The first satellite was placed in orbit on
August1,1999,andthesystemwascommissionedon
September 27, 2007. The system configuration is
showninFig.14.
Figure14.MSASconfiguration[Terada2008]
The Japanese government does not plan to
develop the system. Once QZSS is declared
operational,itisexpectedtotakeoverthefunctionsof
MSAS.
10 INDIANREGIONALNAVIGATIONAL
SATELLITESYSTEM(IRNSS)
BythedecisionofthegovernmentoftheRepublicof
India, a project to build a regional system called
IRNSSwaslaunchedinMay2006. Thedecisionwas
motivated by the concern about the safety of India
and the intention to give India independence from
GPS.Theservicearea ofthesystemwillincludethe
Indian Ocean, South and East Asia, East Africa and
mostofAustralia.
Figure15.IRNSS service area (source:
http://irnss.isro.gov.in/)
The target system constellation will comprise 7
satellites:
4 satellites in geosynchronous orbits at 55°E and
111.75°E,withinclination29°
3satellitesingeostationaryorbitsat32.5°E,83°E
and129.5°E
Thefirstsatelliteofthesystemwasplacedinorbit
in July 2013 and the following
ones‐in April and
October 2014, and March 2015. The fifth satellite
(IRNSS‐1E) was located in a suitable orbital slot on
January 20, 2016. The current system configuration
comprises 5 satellites. The IRNSS system transmits
signals at L5 (1176.45 MHz) and S (2492.048 MHz).
Theremainingtwosatelliteswill
havebeendeployed
by the end of 2016 when the system is expected to
enterfulloperationalstatus.
The positioning accuracy is expected to be 10‐20
meters.Themeasurementsessionsconductedin2015
confirmed the feasibility of reaching the assumed
values.
Figure16. Position error and GDOP coefficient in IRNSS
[Parikh2015]
190
11 GPSAIDEDGEOAUGMENTEDNAVIGATION
(GAGAN)
Indian Space Research Organization (ISRO) and
Airports Authority of India (AAI) agreed to build
their own augmentation satellite system (SBAS) in
August 2001. After WASS, GALILEO and MSAS
GAGAN has been theforth augmentationsystem in
the world. Similarly to other systems of
this kind,
SBASisintendedtoenableaircraftstorelyonGPSfor
allphasesofflight.
Figure17.GAGANservicearea[Indi,Sunda2012]
The space segment of the system consists of 3
geostationarysatelliteslocatedat55°E,82°Eand83°E.
The first satellite, GSAT‐8, was launched in March
2011, the second, GSAT‐10, was inserted in orbit in
April 2012. The last one, GSAT‐15 was launched on
November11,2015fromKourou,
FrenchGuiana.The
groundsegmentiscomposedof15referencestations
(INRES)situatedinthefollowingcities:Ahmedabad,
Bangalore, Bhubaneswar, Kolkata, Delhi, Dibrugarh,
Gaya, Goa, Guwahati, Jaisalmer, Jammu, Nagpur,
Porbandar, Port Blair, Trivandrum. The ground
segment also includes the Indian Master Control
Center (INMCC) in Bangalore which processes data
received
from reference stations to compute
differentialcorrections,andestimatesintegritylevels.
The SBAS messages are broadcast to geostationary
satellites from three Indian Land Uplink Stations
(INLUS)locatedinBangalore(2stations)andDelhi(1
station).
The Directorate‐General for Civil Aviation
(DGCA) confirmed GAGAN for enroute operations
(RNP0.1)onDecember
30,2013andsubsequentlyon
May 19, 2015 certified it for precision approach
services(APV1).GAGANisthefirstSBASsystemin
the world to serve the equatorial region. GAGAN
thoughprimarilydesigned foraviation,willprovide
benefits to many other user segments such as
intelligent maritime, road, railway
transportation,
surveying,securityagencies,telecomindustry,mobile
networks.
Figure18. The ground segment of GAGAN [Indi, Sunda
2012]
12 THREATSTOGNSSOPERATION
Continuouslytransmittingfromorbitsover20,000km
abovetheearth andpoweredbysolar panels, GNSS
signalsreceivedon earth are fainterthan the cosmic
background noise. This makes them very easy to
disrupteitheraccidentallyorpurposefully.Extensive
studies and analyses of these threats are
available
elsewhere. The following outline provides a
summary:
1 GlobalScaleThreats
Solar Activity – Coronal Mass Ejections have
briefly disrupted GNSS reception twice since
2007.Largerand longer lasting instances such
asCarringtonEventin1859havethepotential
toeitherdestroysatellitesand/orground‐based
electronicsand/or
disrupttheionosphereforan
extended period so as to prevent reception of
signals.
HostileMilitaryAction–Fewnationshavethe
abilitytoaccessspaceindependently,letalone
makewar.YettheUnitedStatesmilitaryisvery
concerned about those that are able. Between
2016 and 2020 it plans
to spend $5B on
defensive and offensive space capability in
ordertocounterthisthreat.
Space Debris /Collisions – As space becomes
more crowded with satellites and debris, the
threat grows. While a very low probability
threat to satellites, and even lower to whole
constellations, hostile and other actions
that
createspacedebrisincreasetheriskandthreat
ofcascadingcollisions.
2 RegionalandWideAreaScaleThreats
Hostile Military Action – Most national
militarieshavetheabilitytojamGNSSsignals
overwideareas,andsomehavedoneso.North
Korea has repeatedly jammed signals on the
Korean
peninsula,andwideareajamminghas
beendetected in the UkraineandMiddle‐East
inconjunctionwithmilitaryactions.
Terrorist Action – GNSS jamming devices
effectiveovershortdistanceshavebeenfound
in the possession of terroristgroups. Terrorist
websites have extolled the virtues of GNSS
jamming and spoofing.
Since jamming over
191
larger distances is mostly a matter of a more
powerfultransmitter,itisreasonabletoassume
wide area GNSS jamming by terrorists is a
threat.
3 LocalScaleThreats
Industrial Accidents/Unintentional
Transmissions – US Navy technicians have
twice disrupted GNSS reception in parts of
cities through accidental transmissions.
Sparking
elevators and other electrical
equipmenthavealsobeenfoundtobesources
ofdisruption.
Easily Obtained Illegal Tactical Jamming
Devices – Jamming devices that are effective
fromahundredmeterstotensofkilometersare
easily obtained from any number of vendors
via the internet. Users and possible users
include:
Criminal Enterprises – The US Federal
Bureau of Investigation has published a
notice about use of jamming devices for
theftofhigh value cargo. Similarproblems
have been documented in the UK and
Europe
PrivacySeekingCitizens–Numerouscases
have been documented of telephone and
airportlanding
systemsbeingdisruptedby
“personalprivacydevice”jammersusedby
citizens seeking to avoid surveillance by
employers and others. One small scale
sampling in theUnited States showed 25%
to30%oftrucksinaportareacarryingsuch
devices.Lastyear cranes in aUS container
port were idled
for hours because of
jammingbysuchadevice.
TerroristForces–Lowerpowerdevicescan
also serve the tactical needs of terrorist
organizations. Terrorists have been
apprehendedwithjammingdevicesintheir
possession.
LegalTacticalJammingDevices–Special law
enforcementunitsthatprotectpoliticalleaders
andpolice
SpecialWeaponsandTacticsTeams
are reported to have the ability to jam GNSS
reception over limited distances as part of
their operations. The US military is also
investigating equipping foot soldiers with
devices that wouldalso jamGNSS for use to
prevent improvised explosive devices from
beingtriggered.
Spoofing Devices – Perhaps of even greater
concern are spoofing devices that introduce
hazardously misleading information into
GNSS timing and navigation receivers.
Beginningwithasignalstrengthlessthanthat
of satellite signals, these devices gradually
increase in signal strength until it is slightly
greater and has “captured” the targeted
device.
Previously difficult and expensive to
construct,anexhibitoratahackersconvention
in Las Vegas, Nevada, USA in 2015
demonstrated and published steps for
building a spoofing device from easily
obtained materials. In fact, she sold kits for
spoofersforaround$300.
13 ELORANASAJAMMINGAND
INTERFERENCEMITIGATION
TOOL
The United Kingdom, Saudi Arabia, Russia, China
andSouthKoreaalloperatesomeversionofLoranas
aterrestrialcomplementandbackupforGNSS.Even
thoughtheUnitedStatesshutdownitsLoransystem
in 2010, it has committed to establishing an eLoran
timing system while it develops requirements for
a
largersystemwhichwillalsoprovidepositioning and
navigation[RNTFoundation2015].
Loran/eLoran is a tower‐based hyperbolic
navigation system that is generally effective within
800km of the transmitter, though the range is much
greateroversaltwater.Thesystemwasdevelopedby
theUnited States during World War
II and portable
versions were developed by the US military in the
1960sand1970s.The signal also incorporates a data
channel which was used by the US Navy to
communicatewithsubmarinesinthe1970s.
Loran/eLoran is considered by many as an ideal
complement to and backup for GNSS. It
provides
similar services but has much different
phenomenology than GNSS. Where GNSS is very
high frequency, Loran is low frequency (100kHz).
GNSS is very low power from space while Loran is
very high power from terrestrial towers. Its high
power (350kW to 1 MW) and low frequency also
make Loran/eLoran
very difficult to disrupt. A
receiver with chips enabled for GNSS and eLoran
would be exceptionally difficult to jam and nearly
impossibletospoof.
Many policy professionals believe that
establishment of eLoran systems and wide use of
eLoran chips in navigation and timing receivers
would help eliminate most GNSS jamming and
spoofingbymakingitineffective.
14 CONCLUSIONS
1 Satellite systems have affected many areas of
human activity in the world. The increasing
numberofsystemsofferingsimilarservicesresults
inthegrowingnumberofdifferentreceivers.What
isurgentlyneeded,therefore,istheunificationof
devices so that they could
automatically and
simultaneously use many different systems,
improvingtheaccuracyofestimates.
2 Asthesesystemsarecommonlyusedintheworld,
furtherintegrationofallsatellitesystemsaspartof
GNSSisrequiredandfurthereffortsmustbemade
to make GNSS more immune to increasingly
frequentincidentsofjamming
andspoofing.
3 The eLoran system is currently the best the
technical and scientific solution to allowing for
effective protection of the Global Navigation
SatelliteSystems.
4 Every day human activity around the world
depends upon satellite systems for timing and
navigation. EU Member States should strive to
protect the
GNSS by the construction of
cooperatingnationaleLoranstation.
192
REFERENCES
1.China Satellite Navigation Office (CSNO). 2013. BeiDou
Navigation Satellite System Open Service Performance
Standard(Version1.0),China
2.HeinG.W.2015. CurrentStatus andFuture Perspectives
ofGALILEO&EGNOSS,IAINWorldCongress,Prague,
CzechRepublic
3.IndiC.L.,SundaS.2012.Ionosphericdatacollectionand
analysis over Indian region
‐ Recent results. First
Meeting of ionospheric Studies Task Force (ISTF/1),
Tokio,Japan
4.Januszewski J. 2010. Stacje segmentu naziemnego
nawigacyjnych systemów satelitarnych i systemów je
wspomagających., Prace wydziału nawigacyjnego
AkademiiMorskiejwGdyni,nr25
5.Jean P. 2015 Galileo and EGNOS Programmes Status
Update.TheTenthMeeting
ofInternationalCommittee
onGlobalNavigationSatelliteSystems,Boulder,USA
6.Kogure S. 2015. The Current Status of QZSS Program.
IAINWorldCongress,Prague,CzechRepublic
7.Mirgorodskaya T. 2012. GLONASS Government Policy,
Status and Modernization. 3rd China Satellite
NavigationConference,Guangzhou,China
8.Moriyama H. 2015. Status Update on
the Quasi‐Zenith
Satellite System (QZSS). The Tenth Meeting of
InternationalCommittee onGlobal Navigation Satellite
Systems,Boulder,USA
9.ParikhK.S.2015.UpdateonIndianRegionalNavigation
Satellite System (IRNSS) and GPS Aided Geo
Augmented Navigation (GAGAN). The Tenth Meeting
of International Committee on Global Navigation
SatelliteSystems,Boulder,USA
10.Parkinson B. 2012. GPS for Humanity, Stanford
University,USA
11.Ran Ch. 2015. Update on BeiDou Navigation Satellite
System.TheTenthMeetingofInternational Committee
onGlobalNavigationSatelliteSystems,Boulder,USA
12.Revnivykh S. 2015 GLONASS Status and Evolution,
IAINWorldCongress2015,Prague
13.RNT Foundation 2015.
http://rntfnd.org/2015/12/10/us‐
to‐build‐eloran‐timing‐then‐navigation‐network‐to‐
complement‐gps/
14.Terada K. 2008 Overview of MSAS MTSAT Satellite‐
based Augmentation System. The Third Meeting of
InternationalCommittee onGlobal Navigation Satellite
Systems,Pasadena,USA
