129
1 INTRODUCTION
Safetyofnavigationontheapproachestotheseaports
of the Republic of Poland can be endangered by
increasedmovementofbigships,includingMaersk’s
container vessels and especially liquid natural gas
(LNG) delivering vessels. Gdańsk and Gdynia,
Poland’smainseaportsarelocatedinZatokaGdańska
in the east of Polish seaside. In the west is locat
ed
seaport in Szczecin and new build gas port in
Świnoujście. Gdańsk and Gdynia take most of the
Polishseatrade,having reasonablepartincontainers
transportationonthelinetoandfromChina.
In 2014 deliveries of LNG to Lithuania started
throughseaportofKlaipeda.SomovementonSouth
Balt
icSeahastendencytoincreaseintheclassofbig
transportvessels.Weespeciallyhavetoconfrontnew
requirements and dangers tied with LNG
transportation ships destined to Polish or Lithuania
seaports. Any collision or act of terror can be
devastating for seaport’s i
nfrastructure and
populationofnearestcities.Sothereisstrongneedfor
close monitoring of ships’ movement on the
approachestoPolishmainseaportsandonthemain
searoutesinSouthBalticSeanearofPolishseaside.
Generally,systemhastobebasedonregulationsfrom
states and organizations.Domestic andint
ernational
Safety of Navigation on the Approaches to the Ports
of the Republic of Poland on the Basis of the Radar
System on the Aerostat Platform
K.Szafran&I.Kramarski
InstituteofAviation,Warsaw,Poland
ABSTRACT:The report depictstechnical andorganizational possibilities with anaim to increase situational
awarenessandseatravelsafetyontheentrytoPolishseaportsonthebaseofthededicatedradarsystemonthe
aerostatplatform.Theradarsystembasedontheaerostatcanworkatthea
ltitudeof3,000meters,whichallows
detecting sea vessels and low level flying aircrafts in the range of 150 nm and more. The aerostat based in
SiemirowicegivesopportunitiestomonitormovementsofseavesselsallovertheSouthBalticSea,startingwith
theLithuanianseasidewithKlaipedaseaportintheeastwheretheseaentersZa
tokaGdańskaandTrójmiasto
seaports,movementsalongthe whole Polish seaside upto Sund Straid nearCopenhagen and searoutes all
along south Swedish coast. On those bases, itis possibleto observe movements of sea transports of special
interestincludingMaersk’sbigcontainervesselsandgasdeliveringvesselstoLithuaniaandtoŚwinoujście.
The proposed radar system is using solutions of towed aerost
ats tested in working conditions which are
exploitedbytheUnitedStatesofAmericatomonitoritsborderwithMexicoandtoobservemovementsofsea
vesselsandlowflyingaircraftsaroundFloridaPeninsulaandPuertoRicoislandsontheCa
ribbean.Theradar
systemsusedbytheUSAaredepictedwithorganizationalrulesoftheirexploitation.Advantagesandthese
advantagesof such a radar system were depicted and some information about dangers related to aerostat’s
exploitation is also provided. Additional possibilit
ies of using the radar system based on the aerostat are
depictedintheroleofanewandimportantpartofthecountry’sdefensesystem.
http://www.transnav.eu
the International Journal
on Marine Navigation
and Safety of Sea Transportation
Volume 9
Number 1
March 2015
DOI:10.12716/1001.09.01.16
130
lawshavetobecomplied.Weneedtobaseonsolid
geo data with known all water and underwater
obstaclesaswellaswaterdeepanditschangeinthe
time.Weneedtoknowactualweatherandseastate
and forecasts for next hours and days. On such
environment
wecanputdataofport’straffic,trackof
approachingvesselsandtheiridentitiesandalertsof
detectedsuspiciousvesselsorfuturesuspectedillegal
activities. We get those data from national or
European agencies, organizations and service
providersandfuseallthedatatoobtainclearpicture
ofactualsituation
andawarenessofpossibledangers.
In ideal world we have to cope with natural
disasters and technical dangers only. But in real
world we have to cope with people’s lack of
knowledge and experiences, tiredness and sickness,
which end up with misinterpretation of facts or
overload. But we also have to
cope with illegal
activities,includingtraffickingofpeople,weaponand
drags and even including acts of terrorism against
high value vessels, passengers, seaport’s
infrastructureandcitizensofseaports.Therearealot
of evidences of usesmall boats for attacking vessels
on the open sea and in seaports, including suicide
attacks to cause many casualties and destroy port’s
infrastructure.
Onthebaseonexperiencesinsomecountrieswe
are proposing aerostat radar system to monitor
activityonapproachestoseaportsandbythismeans
to increase awareness and safety of sea travel and
transportation.
2 TETHEREDAEROSTATRADARSYSTEM
The most
widely used aerostat radar system is
Tethered Aerostat Radar System (TARS) which is
operated by US Homeland Security Department on
USAsouthlandandseaborders[6].
TARS was developed in the 1980s to protect US
southernborder against drag and people trafficking.
Systemiscomposedoftetheredaerostatwith
airborne
radar subsystem and ground base with power to
analyzeradardataandsendthemtocommandposts.
Security system of US southern border is shown in
Figure1.Aerostatscanhover ataltitudeupto 4.500
meters but typical working altitude is 3.000 meter.
Most of TARS aerostats are operating
on land in
Texas,NewMexicoandArizonastates butthereare
alsoaerostatsusedtomonitorStraitsofFlorida (base
onCudjoeKeyislandinKeyWestarchipelago)andof
Puerto Rico (base is on south west side of island).
United Arab Emirates have build base for aerostat
radar
system to monitor movement of vessels in
StraitsofOrmuzwhichistheonlywaytoentertoand
departfromPersianGulf.RepublicofSingaporehas
justannouncedpurchaseofaerostatradarsystemfor
monitoring of Straits of Malacca, one of the most
importantseawaysintheworld.
In
the same time Kingdom of Malaysia has
decidedtopurchaseaerostatradarsystemtomonitor
situationonthenorthpartofBorneoIsland.
Scarce information are only available about
aerostatradarsystemsoperatedinIsraelwithviewon
approaches to Haifa seaport on the Mediterranean
and Gulf of Aqaba on
Red Sea and about aerostats
stationed on the both sides of Strait of Taiwan and
operated by Republic of China (Taiwan) and China
PeopleRepublic.Thereasonforsuchsecrecyisdesire
to protect information about performances of radars
used in those aerostat radar systems. Those aerostat
radar systems primarily are
connect to national
defense systems to provide better awareness and
protectownmilitaryandeconomyassetsagainstany
adversary. The secondary role is the monitoring of
movement of civil vessels and work for safety of
navigationofapproachingforeignerships.Sampleof
sea mobile radar system for aerostat is shown
in
Figure2.
Figure1.TARSaerostatradarsystemlocationsonsouthern
borderofUnitedStatesofAmerica(USCustomsandBorder
Protection‐http://www.cbp.gov/frontline/2014/10/frontline‐
november‐aerostats).
Figure2. Sea Based Aerostat moored to deck of Abshire
Tide vessel (http://www.tcomlp.com/gallery/sea‐based‐
aerostats/)
Aerostat radar systems add new possibilities to
observe sea waters; seasides and seaports from the
air. Using of radars aerostat radar systems can
provide wide range surveillance in ranges up to
hundreds of nautical miles and by using in
combination of electro‐optical sensors (EO) can
recognize approaching vessels and monitor
theirs
behavior on short distances. Such bird view can be
maintained by utilizing fixed wing and rotary
aircrafts. But those assets are typically more costly
andcannotprovidepersistentsurveillancebecauseof
restricted time of flight (fuel consumption and crew
tiredness).Unmannedairsystems(UAS)areentering
marketofpersistent
surveillancebuttheyareattheir
infancy yet and have to confront requirements of
regulationsandmental obstacles. From thecost side
131
of view, UAS are not as cheap as expected in
comparison with manned and land observation
systems.LeastreportofUSHomelandSecurityOffice
of Inspector General put some light on real costs of
exploitation of UAS on south border with Mexico.
UASs using sophisticated EO systems in stabilized
gimbals
and 3D radars have only small part in
apprehensions of traffickers smuggling drags and
people.Becauseofrestrictionsofuseincivilairspace
UAS can be used only in some small and strictly
designatedpartsofairspace.Sotheirsviewisnarrow
and restricted and should to be
threaten as
complementarytoothercapabilities.
In2010wasstartedprojectcalledI2C‐Integrated
System for Interoperable Sensors & Information
Sources for Common Abnormal Vessel Behavior
Detection & Collaborative Identification of Threat.
ThisinternationalEuropeanprojectwas implemented
to enable automatic identification and tracking of
vessels suspected of involvement in irregular
migration, illegal fishing, and drug trafficking and
looting of cultural heritage and reporting on
EUROSUR (European Border Surveillance System).
With the financial help of European Commission
companies from some European countries have
designed and tested in simulated conditions
integrated I2C system. The I2C system acquires
informationfrommultiplesources, including
coastal
radars,aircraft,andairshipandobservationsatellites.
This data is analyzed using high‐performance
algorithmic software to correlate and exploit all the
informationtoassessvesseltrajectoriesandactivities
dynamically,interrogatedatabasesandautomatically
raise alerts according to established rules in
consultation with the operational authorities.
Airbornepartofthis
Europeanearlywarningsystem
isshowninFigure3.
Figure3.AirshipduringI2CtrialsonsouthshoreofFrance
(www.i2c.eu).
To improve system possibilities airship was
involved in the tests. Airship was equipped with
radar and electro‐optical observation system in
stabilized gimbals. Data from airship’s sensors was
analyzed on board and send to command center on
land.ThereareplanstocontinuedevelopmentofI2C
systemsinthenextyears.
But disadvantage of manned and unmanned air
systemsistheirsdependencyonweatherconditions.
Theycannotbeexploitedinbadweatherconditions,
so cannot help in emergency situations. Aerostats
moored to ground station have proved their
capabilities in harsh weather conditions with wind
speedsupto60kts.
3 AEROSTAT
RADARSYSTEMDESCRIPTION
Aerostatradarsystemconsistsof:
1 Aerostatwithtether,
2 Airborne radar subsystem with electro‐optical
sensorsingimbals(optional),
3 Groundcarwithmooringtowerandwinchsystem
fortether,
4 Ground station for processing, analyze and
distributingofsignalsfromradarsystem,
5 Groundauxiliaryequipment.
Aerostat has non rigid structure without inner
skeleton. Aerodynamic shape is provided by
overpressureoffillinggas‐typicallyhelium.Airship
canopyismadefromhighstrengthNylonfabricwith
polyurethane and Tedlar layers to obtain tightness
and sturdiness for weather conditions. Canopy has
two air pressured ballonets, in front and
aft of
aerostat,toprovidestabilityintheairstreamandto
compensate helium volume changes depending on
temperaturechangesinsidecanopy.Stabilizersonaft
of aerostat are filled by pressured air to maintain
proper aerodynamic shape. The radar system’s
antennaontetheredaerostatisshowninFigure4.
In bottom
aft part of aerostat’s canopy radar
compartmentareusuallymounted.Radarantennais
undershieldwitchaerodynamicshapeismaintained
byairpressure.Undershieldarealsomounteddiesel
electricpowergenerator,airblowersforballonets,air
blowers for stabilizers and communication pack for
sending crude radar signals to ground
base station.
To lower mass of airborne radar subsystem on
aerostat are mounted only antenna and
communicationpack.Cruderadarsignalsaresending
togroundstationandprocessedbyspeedy computers
(alotofelectricpowerisneededforthiswork).When
all fuel is burn by diesel electric power generator
aerostathavetobepullfromaltitudeandmooredto
ground base for fuel filling and for maintenance
works on airborne subsystems. In newest aerostat
radar systems like JLENS special tether was
introduced.Insidetetherareelectriccablesaswellas
optical fibers for control and communication. So,
there is
no need for every few day fuel filling and
communication between antenna and ground
processing station are secured and immune of
interferences. But such integrated tether is heavier,
more costly and has unknown durability (during
work on altitude aerostat is exposed on harsh wind
blowswhichgeneratehighloadsontether).
132
Figure4. Aerostat radar system on Cudjoe Key Island on
Straits of Florida (base for two aerostats)
(http://en.wikipedia.org/wiki/Tethered_Aerostat_Radar_Sys
tem
Airborne radar subsystem is composed of
rotational antenna and communication pack.
Dependingonwinddirectionandresultedfromthis
direction of aerostat in air, rotational radar antenna
provides full coverage of surrounding space. All
processingofcruderadarsignalsaredoneinground
processing station to lower mass of airborne radar
subsystem.
Range of radar detection is directly tied with
curvature of Earth and operational altitude of
aerostat. Even smallest altitude can provide much
wider radar view in comparison with land radar
systems.According to specificationTARS aerostat
systemcandetectnavalactivityandlowflyingsmall
aircrafts from distance up
to 200 nm (operational
altitude is 3.000 meters) and JLENS with more
sophisticatedradarcandetectobjectsfromupto300
nm. Ground station has round place with car with
mooringtowerforaerostat.Towerismountedonthe
topofrotationalcar with winchfor tether. Car with
tower and
winch can rotate to allow take any
direction depending on wind direction in the
sequenceofmooringaerostat.
Figure5.Rotationalradarantennaundermaintenance
Ground station takes crude data from airborne
radar antenna and processes it by using station’s
computer systems. By this way processing of radar
signals is done on the ground, not on the board of
aerostat. Computer systems for signals’ processing
areonthegroundandtheyuseelectricenergyfrom
land
sources. So radar system on the aerostat can
havelowerweightandbythismeanaerostatcanbe
smaller(it’salsomeancheaper)orcanworkonhigher
altitude(greaterrange).
Figure6. Range of aerostat radar system depending on its
altitude and height of observed vessel (Ireneusz
KRAMARSKI)
Processed data can be distributed to monitoring
system on higher level of command (navigation,
emergency,defense,scientificpurposesetc.).
Table1.Calculationofradar’svisibility(basedoncalculator
onhttp://members.home.nl/7seas/radcalc.htm)
_______________________________________________
Radar’sHeightof Visual Radar
altitude‐H[m] vessel‐h[m] Horizon[nm]Horizon[nm]
_______________________________________________
2531315
30033642
60035058
100036474
30003108125
_______________________________________________
4 POLANDAEROSTATRADARPROGRAM
In1990 yearsin Poland aerostat radar program was
startedincooperationofInstituteofAviationandPIT
Company. Working jointly, specialists from the
Institute of Aviation and Przemysłowy Instytut
Telekomunikacji (now PIT‐RADWAR SA) finally
came to the idea of designing the observational
system, including aerodynamically shaped,
unmanned, tethered aerostat carrying the airborne
radarwithstationaryomnidirectional (nondirectional
and non rotational) antenna, and being controlled
from ground situated control centre. Such system
shows a lot of advantages over widely known
airplane installed AWACS facilities: longer
endurance, relatively smaller horizontal speed
between antenna
and object (an important factor of
the radar return measurement process), operational
safetyandlowcostofexploitation.[2,3].
On large aerostats radar antenna is mounted
underspecialgondolaunderaerostatbelly.Onsmall
aerostats radar antenna is mounted under belly,
typically with addition of EO system (smaller
operationalaltitude
andlowerrangeofobservation).
BecauseofmediumsizeofdesignedSK‐1system,
designers choose to mount radar antenna inside
aerostat belly. Radar antenna with such dimensions
would require gondola of reasonable size and with
high front area which can severely affect
performancesoftheaerostat.
133
Table2.Comparisonofgroundandairborneradarsystems
_______________________________________________
Parametersof GroundradarAirborneradarAirborne
radar
observation system systemon systemon
system(mobile) aircraftaerostat
_______________________________________________
Rangeoflowveryhigh high
observation (25‐50nm) (150‐300nm) (50‐150nm)
Timeofnonstoplongshortlong
operation (week– (upto(week‐
months) 10hours) months)
Mobilityof highveryhigh low
system
Numberof lowveryhigh low
system
Resistanceof veryhigh
highveryhigh
weatherconditions
Costoflowveryhigh high
purchase
Costsof lowveryhigh low–
medium
operations
_______________________________________________
Figure7. SK‐1 aerostat radar system project with
omnidirectional (non rotational) antenna (Krzysztof
SZAFRAN)[4].
Aerodynamically shaped, SK‐1 tethered aerostat
radarsystem was destined to use for observation of
objectsmovingonthegroundandwatersurfacesand
objects flying not higher than 300 meters inside the
circled area with 75 nm radius. Rough estimations
show that it is possible to observe such area
effectively
fromthesystemworkingatthealtitudeof
500movertheground/waterlevel.
Table3. Specific parameters of SK‐1 aerostat radar system
(ILot2000)[5].
_______________________________________________
Length38m
Diameter10m
Volume2500m3
Weightofradarantenna200kg
Dimensionsofantenna(DxL)6.6x1.5m
Maxweightofpayload(airborneequipment1000kg
includingtetherline)Operationalaltitude 300‐500m
Operationalrangeofradarsystemupto75nm
Operational
temperatures‐40‐+45
0
C
Weatherconditionswind,rain,snow
_______________________________________________
Tetherwouldmoreaerostattotheground,provide
electrical power to airborne subsystems on board of
aerostat and provide communication and control of
airbornesubsystemsbyuseofopticalfibers.
5 BOS‐2SPATIALOBSERVATIONAEROSTAT
To learn some experiences with handling and
operatingofaerostatinrealconditions and to
check
some technical solutions a smaller demonstrator of
aerostat was designed, developed and produced.
NamedBOS‐2,ithashadlengthof10m,diameterof
3 m and volume of 50 cubic meters. It can take
payloadofupto25kgtoattitudeofupto150meters.
[5].
Figure8.BOS‐2aerostatdemonstrator—firstvariantwith
simplified stabilizers‐on International Defense Industry
Exhibition MSPO in Kielce, Poland (Ireneusz
KRAMARSKI).
Technology demonstrator was used in full scale
trialsinsemirealconditions.Becauseoflackofradar
system with small mass, only EO system was used
during tests. In those times EO system was analog
system with heavy weight optics and complicated
stabilization in gimbals. But we have learned a lot
about handling, operating and transport of tethered
aerostatsystem.
Inthenext years aerostatdemonstratorwasused
in trials with new lighter EO system in cooperation
with Polish Instytut Techniczny Wojsk Lotniczych
(Air Force Institute of Technology) and in such
configurationhastakenpartinInternationalDefense
IndustryExhibitionMSPO
inKielce,Poland.
Onthebaseoftrialsnewstabilizersweredesigned
withbiggersizeandbetteraerodynamicefficiency.
Butinthemeantime someprogress was made in
electronics and optics, as well as in gimbals
stabilizationandcommunicationsubsystems.
So on this base a new project was started under
name
SOPEL.Itissmalltetheredaerostatsystemwith
multipurpose gondola (stabilized gimbals with day
and low light camera and infrared camera as well,
134
weather sensors, pollution sensors). Weight of the
gondola is up to 7 kg. Aerostat has length of 6.5
metersanddiameterof2.3meterswithvolumemore
20cubicmeters.Itcanoperateonaltitudesupto150
meters.
ItisnowintroducingforUAVvehiclestestingasa
mean
tomonitorflyingvehiclesandretranslatetheirs
signalstogroundcommandstation.Biggeraerostatis
planned for small sophisticated radar system which
canbeusedinmonitoringofland,seasideandwater.
Figure 9. SOPEL aerostat system with multipurpose
gondola and trailer with winch and compressor (Ireneusz
KRAMARSKI)
6 CONCLUSION
Lessonslearned
1 It is feasible to design and manufacture aerostat
radar system with satisfactory performances
(radar range and weather resistance) and
reasonablecostsofpurchaseandoperations;
2 Steady progress in electronics provide new
possibilitiesforaerostatsystemmarketutilization
andfornewapplications;
3 Specific needs generate
specific radar and EO
equipment and on this base should be designed
tetheredaerostatsystem;
4 More volume of aerostat more problems with
handling,transportationandoperation,andmore
all purchase and operational costs (helium, crew,
groundstationormobilestationetc.);
5 Smalleraerostatsystemsallowforheliumrecovery
in reasonably time by using mobile compressors;
morevolumelesscapabilityofmobility.
After a lot of years aerostats are returning to
operational use. Main reason is theirs long time on
stationandresistanceforweatherconditions.
It is possible to operate a few of tethered
small/mediummonitoringsystemsinnon
crewmode.
Tethered aerostats, and especially those in
positionsof mobile lead observations in a variety of
field conditions. Position BOS‐2 was tested in forest
areas to observe fire hazard. Attempts were also
conducted follow‐up of road traffic on the routes of
communication. Platform together with the
observation
systemhasmetexpectations.
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BP‐3/45/99.1999,113str.
[3]SZAFRAN K. – Bezpilotowe stanowisko obserwacji
przestrzennej.InstytutLotnictwa,BP‐3/32/98.1998,77str.
[4]SZAFRAN K.& zespół –
Projekt techniczny, Platforma
balonowa jako uniwersalny nosiciel systemów obser‐
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[6]USCustomsandBorderProtection’sUnmannedAircraft
SystemProgramDoesNotAchieveIntended
Resultsor
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