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1 INTRODUCTION
Marine traffic near the Korean sea coast has been
increased by economic growth. The increase of
marinetraffichascausedcongestionandhasbeenone
ofthecausesofmarineaccident[1].Accordingtothe
marineaccidentstatisticaldatafromtheKoreaCoast
Guard,thenumberofmarine
accidentshasincreased
every year since 2004 showing that 4,172 ships
encounteredmarineaccidentsbetween2004and2008.
The annual average number of marine accidents in
the past five years was 834 [2]. The most frequent
marine accident was ship collisions caused by the
failure of radar detecting. Human error
was a large
part of the reasonforcollisionaccidents.One of the
main reasons of human error is negligence of
navigationwatchingkeeping. Therefore,International
Maritime Organization (IMO) emphasizes the
importance of keeping a navigational watch by
regulations[3]
Recently, sea pirate attacks and armed robbery
againstships haveincreased
considerably,according
to the International Maritime Bureau (IMB) [4].
According to a report from The United Nations
International Maritime Organization (IMO) and the
IMB,293seapirateattackswerereportedandofthose
49 ships were kidnapped [5]. The IMO recommends
the installation of marine surveillance equipment
(Day/Night Vision) to
secure navigation safety from
pirateattacksandshipcollisions[6].Inaddition,the
United States enacted the ISPS code after the 911
terror attacks and required that ships be equipped
with the security and surveillance system[7][8].
Consequently, shipping companies started to install
the marine surveillance equipment and the related
industrial
market is expected to expand gradually.
Therelatedregulationswasimproved[9]
Nowadays, many studies are carried out on
navigation visual supporting systems. A study used
The Development of Ship Watch Keeping Supporting
Aids
N.Im,E.K.Kim,S.H.Han,J.S.Jeong&S.M.Lee
M
okpoNationalMaritimeUniversity,Mokpo,SouthKorea
KunsanNationalUniversity,Kunsan,SouthKorea
ABSTRACT:Thisstudydealswiththedevelopmentofshipwatchkeepingsupporting aidsthatwillbeuseful
forshipdeckofficersinrecognizingnavigationalharmfulobstaclessuchasseamarksandsmallfloatingobjects
onthesea.
Thedevelopedwatchkeepingsupportingaidsismadeupoffourcomponents;acompositevideo
sensortoproducevideosignal,alaserdistancemeasuringpart,aPan/Tiltpartandacentralcontrolpart.The
system was installed in a ship in order to verify its performance of the recognition ability on
the sea. The
comparisonwasmadebetweentherecognitionabilityofthesystemandthatofwatchkeepingdeckofficers’.
The image from the watch keeping supporting system was found to be more recognizable than that of a
binoculartelescopewithina5kmdistance.Thenewlysuggestedsystemis
expectedtobeusedtorecognize
smalldangerousfloatingobjectsmoreeasilywhennavigationdeckofficers haveadutyofwatchkeepingfor
navigationespeciallynearharborarea.
http://www.transnav.eu
the International Journal
on Marine Navigation
and Safety of Sea Transportation
Volume 7
Number 4
December 2013
DOI:10.12716/1001.07.04.04
502
the data of RADAR ARPA for development of
navigationobservationsystem[10][11][12].According
to the E‐Navigaton strategic plan of IMO, the
importance of maritime situation awareness for safe
navigationisemphasized[13].Howevertherealityis
thatthemajormeanofmaritimesituationawareness
is binocular telescopes with the
help of ARPA and
AIS.
This study describes the development of
navigationwatchkeepingsupportingsystemthatcan
improve recognition ability for navigational harmful
obstacles.Thesystemwasinstalledinashipinorder
toverifyitsperformanceoftherecognitionabilityon
the sea. The image from the watch
keeping
supportingsystemwasfoundtobemorerecognizable
than that of a binocular telescope within a 5 km
distance.
2 CONFUGURATIONANDFUNCTION
Radar has been used as one of the essential tools of
navigation equipment. However it has trouble
recognizingsmall floatingobjectson thesea.In case
of
abinoculartelescope,ithaslimitationsofdetecting
andrecognizingfloatingobjectsseveralnauticalmiles
away.
In this study, the navigation visual supporting
systemwasdeveloped tomakeupfor the weakness
of existing navigation equipment. Since visual
informationsuchasa video image is provided on a
monitor, navigators
can easily recognize small
dangerousobjectssuchasmarinemarks.Thepurpose
ofthesystemistoimprovetherecognitionabilityfor
maritime situation awareness, one of the important
factorsfornavigationsafetyonthesea.
Pan/Tilt Driver
Housing
Composite video
Sensor
Central Control Unit
Laser Range
Finder
Tilt
encoder
Tilt
Motor
Tilt
Motor
Driver
Pan
encoder
Pan
Motor
Pan
Motor
Driver
Controll
er
Display
Monitor
Display
Monitor
Central
Control
Sever
VGA
U.V.W.
U.V.W.
EnDat Seroal
EnDat Seroal
RS232
RS232
Zoom In/Out
Video Signal
Range Data
Order for Range
Control for
Pan/Tilt
Figure1.TheOperatingprincipleofvisualnavigationalaids
The system provides visual information about
dangerousfloatingobjectsaroundashipusingalaser
distancemeasuring technique and video signals
fromcompositevideosensors.Thesystemconsistsofa
compositevideosensorforvideosignals,alaserdistance
measuringunit,aPan/Tiltunit,andacentralcontrolunit.
Theconfiguration
isshowninfigure.1.Theoperationsof
thejoystickinthecentralcontrolunitgivecommandsto
eachunitthroughthecontrollerinthePan/Tiltunit.Each
unitcarriesout theorderaccordingtothesignalsfrom the
controllerofthePan/Tiltunit.
Atthistime,thecollected
dataistransferredtothe
centralcontrolunitandtherelatedinformationsuch
asatargetimageandthedistancebetweenthe ship
and the target are displayed on the monitor. The
particularsofnavigationvisualsupportingsystemare
shownintable1.Theoutlineandconnectionbetween
eachpartare
explainedinfigure2.
Table1. Figures of Real time front observation navigation
System
_______________________________________________
ParameterUnitValue
_______________________________________________
Drivingrangedeg360
Accuracyofanglemrad1mrad
Detectionrangeofragerm10,000
Accuracyofdistancem±5
PowerofragermJ,ns4,30
wavelengthofrager㎛1.54
typeofrager‐Erglass
weightkg1.5
PowerlossW25
lossinformationpixel1.3M
Opticalzoom‐12
Distanceof
detectionkm<5.0
_______________________________________________
Figure2.Outlineofthesystem
2.1 CompositevideoSensor
The Image sensor module for navigation equipment
basicallyhasthesameobservationfunctioncompared
with a general camera CCD. However, it requires
durability and waterproofed structure and design
since it is operated in the harsh conditions of sea
environment. In addition, visual information
connected to ship operations
should be provided in
realtime.
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Inthisstudy,thecompositeimagesensorisused
for the front monitoring and gets the image from
camera CCD and LLCCD. With a telephoto lens,
magnification can be adjusted appropriately. As
shown in figure 3, the image sensor for the front
monitoring consists of five main parts. The
specifications
ofeachpartareexplainedinTable2.
Figure3.Mainelementpartsofimagingsensor
Table2.Featuresofcompleximagingsensor
_______________________________________________
ParameterValueUnit
_______________________________________________
ImageFormat½inch
FocalLength8~96mm
IrisF1.6~1000 Video
MountTypeC‐
Temp.Range‐10~+50
Size130×77×87 mm
Weight1.2kg
Power12VDC
ExternalcommunicationUART,12C,SPI
_______________________________________________
2.2 Laserdistancemeasuringunit
The laser distance measuring unit provides the
distanceinformationbetweentargetsandaship.The
bearing of the targets can be easily obtained by the
Pan/Tilt unit. However, it is necessary to get the
distance information from the laser distance
measuringunitinorderto
fixthetarget’spositionon
aseachart.
Table3.Featuresoflaserrangefinder
_______________________________________________
ParameterValueUnit
_______________________________________________
Wavelength1.54μm
Supplypower5mJ
Pulsewidth30nsec
Beamdivergenceangle0.5mrad
Repetitionratio2(Max.)Hz
Size155×110×225 mm
Weight3.5kg
_______________________________________________
The laser distance measuring unit calculates the
distancebetweenatargetandashipbymeasuringthe
timeofflightforaradiatedlaser.Itusesahighoutput
and small pulse laser because it is safer for human
eyes. The distance measured by the laser distance
measuringunit
ismoreaccuratecomparedtothatof
existingRadarsystems.Ithasadistanceerrorofless
than several meters. Besides, this unit has the
advantageofbeingcompactandlight.
In this study, the laser distance measuring unit
detected and recognized small floating objects and
ships within 10km. The specification
of the laser
distancemeasuringunitisexplainedintable3.
2.3 Pan/Tiltunit
The navigationvisual supporting system is required
todetectdangerousobjectsfromeverydirection.
The Pan/Tilt unit enables the system to move
vertically and to rotate a full 360‐degree. The unit
consists of an observation
window, controlling
algorithms, a drive, and a special housing that
protects the system in the harsh conditions of a sea
environment. Figure 4 shows the main body of the
developedPan/Tiltunit.Theimagesignalsensorand
thelaserdistancemeasuring unitaremountedinside
the housing. A type of slip
ring was adopted in the
rotaryPantosecurerotarymotions.Thespecification
ofthePan/TiltunitisshowninTable4.
Figure4.BodyofPan/Tilt
Table4.FeaturesofPan/Tilt
_______________________________________________
ParameterValueUnit
_______________________________________________
AcuatorDD(Directdrive)SERVOSYSTEM‐
Supplypower 85VAC～265VACVAC
Actionspeed PAN:0.1∼90
TILT:0.1∼40°/sec
Drivingrange PAN:360Endless /
TILT:‐30∼+30°
Temp.Range‐40∼+50°c
Size530(L)X280(W)X390(H)mm
Weight
60Kg
TextureSUS316,AL6061‐
Opticaldevicef:10∼500mmvidualzoomcamera ‐
TypeofControl RS‐422‐
Signaling
Signalingspeed 9600bps‐
Typeofprotocol PELCO‐D‐
SoftwareGUISoftware‐
_______________________________________________
2.4 Centralcontrolunit
Thecentralcontrolunitreceivesdistanceinformation
and bearing data from the laser distance measuring
unit and the composite image sensor unit
504
respectively. The information is displayed on the
monitorofthe centralcontrolunit.Themonitoralso
displaysthevisualimagedetectedby the composite
imagesensor.Figure5showsthecentralcontrolunit
that consists of a monitor, a joystick controller, a
controlserver,andarack.Eachpartis
accommodated
intherack.
Figure5.CentralController
2.4.1 Monitor
A marine type monitor is adopted in order to
identify the screen data more easily in navigation
environments.Themonitordisplayconsistsofamain
screen and menu tools that enable users to zoom in
andoutofthemainscreen.Figure6showsthepicture
of the monitor
and its specification is shown in
table.5.
Figure6.ThemonitorofCentralController
Table5.Featuresofthemonitorofcentralcontroller
_______________________________________________
ParameterValueUnit
_______________________________________________
Size20.1inch
ActiveArea408*306mm
Resolution1600*1200dpi
Contrast300:1‐
Light250Cd/m
FieldofView85°
_______________________________________________
2.4.2 Keyboard
The keyboard of this system has multi‐function
controls since it is specifically designed to control a
CCTV system. A receiver can control the Pan/Tilt
motions, its power systems and the laser distance
measuringunit.Thestatusofthesystemisdisplayed
ontheLCDmonitor.Thedetails
ofthekeyboardand
itsspecificationisshownintable6.
Table6.FeaturesoftheJoystickofcentralcontroller
_______________________________________________
ParameterValue
_______________________________________________
TypeofControlSignalingRS232,RS485,RS422
Preset256
StepofControlSpeed10
Supplypower12
_______________________________________________
2.4.3 Controlsever
Thecontrolserverreceivesananalogimagesignal
fromthecompositeimagesensor.Theanalogimageis
saved in a built‐in HDD using the compression
algorithm of the H. 262. The control server displays
thesavedimageinthemonitorinrealtime.Thesaved
image
can be replayed and searched by the built‐in
software. The control software displays split screens
and provides several functions like the control of
Pan/TiltthroughtheGUI,theloggingofstatusdata,
theadjustingofasearchrange,and thedisplayofa
laserdistance.Thespecificationisshown
intable7.
Table7.Featuresofthecontrolsever
_______________________________________________
ParameterValues
_______________________________________________
TypeofProcessor IntelCoreTM2duo
HDD2.5”160
EmbeddedCache 256KB´4,L2
processorFSB1333
MainMemory2x240‐pinDDR2667to2.0GB.
OnbordLanFeatures TwoRealtekRTL8111CPCI
ExpressGigabitcontrollers
AudioFeaturesRealtekALC662HighDefinition
audioCODEC
_______________________________________________
3 SEATRIALTEST
Sea trial test were carried out in order to verify the
performanceofthesystem.Oneofthetrainingships
of Mokpo maritime university was used for the sea
testintheareabetweenMokpoandKwang‐Yang.
3.1 Theinstallationofthesystemonboard
The Pan/Tilt was mounted on the campus deck, the
highest floor on the training ship, in order to easily
detecttargetsfromahighposition.Thecentralcontrol
unit was installed on the bridge deck where
navigation officers watch the image on the system’s
monitor.Figures7and8show
thePan/Tiltunitonthe
campus deck and the central control unit on the
bridgedeck.
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Figure7.ThePan‐tiltoncompassdeck
Figure8.Thecentralcontrollerinthebridge
3.2 Theresultofseatrialtests
Theseatrialtestswerecarriedoutontheconditionof
theweatherandtheseastateasshowninTable.8.The
arrangementofthetargetsandtheshipisindicatedin
figure9.
First, lighthouses and sea marks were designated as
targetsof
whichdistancesweremeasuredbyradarandasea
chart.Then,thesetargetsweredetectedbythesystem
and their images were displayed on the monitor in
order to verify the system’s recognition ability.
Finally, the images were compared with that of a
binoculartelescopeandnakedeyes.Thedetails
oftargets
areshownintable.9.
The detected images from the system are shown in
figures10‐13.
TargetAintable9wasalighthouse5200mawayfrom
the sea trial ship. The target was dimly visible but not
clearlyrecognizablebyabinoculartelescopeandnaked
eyesat
thattime.Howeveritwasfoundthatthesystem
provided the image as shown in figure 10 where the
targetwasmorerecognizable.TargetBintable9wasa
smalllighthousewhichwasnotvisiblewithnakedeyesat
thedistanceof3700meters.Avaguefigurewasjust
seen
even by a binocular telescope. However, the system
showedmoreaclearandrecognizableimageasshownin
figure 11. The image provided by the system made it
possibletorecognizethetargetasalighthouse.
TargetCandDintable9weresmallfloatingsea
marks. It was
relatively difficult to recognize these
targets with naked eyes or a binocular telescope.
Figure12showstheimageofthetargetCobtainedby
thesystem.Itwaspossibletorecognizethetarget at
thedistanceof3300meters.TheimageofTargetDis
showninfigure13.It
waseasilyrecognizablebythe
systematthedistanceof5370meters. Theresultsof
theseatrialtestsindicatedthattheimagesfromthe
systemweremoreclearandrecognizablethanthatof
a binocular telescope within a 5 km radius. The
system detected and recognized the targets more
effectively
and easily compared to a binocular
telescopeornakedeyes.
These tests indicated that the developed system
couldbeusedtorecognizesmallbuoysordangerous
floating objects in a harbor area more easily and
quickly
Table8.Thestateofsea
_______________________________________________
ItemsDimensions
_______________________________________________
SeaConditionBeaufortScale3
WindSeed5knot
VisibilityScale4
SeaWave0.6m
_______________________________________________
Figure9.Thearrangementoftargets
Table9.Thefeaturesoftargets
_______________________________________________
Target‐A Target‐B Target‐C Target‐D
_______________________________________________
TypeLighthouseLightedBuoy
Distance(m) 5200 3700 3300 5370
Height(m) 119.35.65.6
Breath 4‐52.32.02.0
_______________________________________________
Figure10.ThesnapshotoftargetA
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Figure11.ThesnapshotoftargetB
Figure12.ThesnapshotoftargetC
Figure13.ThesnapshotoftargetD
4 CONCLUSIONSANDFUTUREWORKS
Thisstudy describedthedevelopednavigationvisual
supporting system which will improve maritime
situation awareness. The system has the merit of
showingtargetsinamonitorvisuallyandrecognizing
smalltargetsinrealtime.Itcouldbeusedtomakeup
fortheweaknessofexisting
Radar,sinceRadarcan’t
provide any information about the recognition of
targets.
Thedevelopedsystemwasmountedinatraining
ship for sea trail tests to evaluate the recognition
abilityforbuoyageandlighthouses.Theimagesfrom
the system were compared with that of a binocular
telescope. It was found
that the images from the
systemweremoreclearandrecognizablethanthatof
a binocular telescope within a 5 km radius. The
developed system could be used to recognize small
buoysordangerousfloatingobjectsinaharborarea
moreeasilyandquickly.
ACKNOWLEDGEMENT
This research was a part of
the project titled
ʺDevelopment of the Intelligent Technology for
Marine Accident Protection & Salvageʺ funded by
theMinistryofLand,TransportandMaritimeAffairs,
Korea.
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