317
1 INTRODUCTION
1
st
of July 2015 will be half of the period of
mandatoryElectronicChartDisplayandInformation
System (ECDIS) implementation. This six‐year
implementationperiodappearsasalong‐termlook‐
ahead;however,takingtheenormouschangeandthe
need to adapt in consideration, it requires certain
issues to be solved properly and, ab
ove all, timely.
Afterthe implementation ending date, therewill be
increasinglylesstimeforsolvingorreviewingarising
problems.Itespeciallyreferstopositioning,whichis
by mandatory means incorporated in the ECDIS
system,acting as anintegratedpart of it. Here,itis
not about a traditional classification of ma
ritime
navigation in general and coastal navigation, but
about a fact that reliable positioning and its
redundancyrepresentsfundamentalsafetyfactoron‐
board navigating vessels. Positioning methods
dependonthenatureofthetypeofnavigationwhich
takes place as well as available positioning means.
Global Navigation Satellite Systems (GNSSs) are
nowadays used as prima
ry positioning sources in
ECDIS.Theyprovidemostreliableandmostaccurate
positions among others; however they are not
immune to errors and failures. The safety of
navigationrequiresausageofsecondarypositioning
sourceinECDISsystemasatrustyredundancyback‐
up in the case of potentia
l primary positioning
failure.Moreover,thereappearsastrongneedforits
Navigation with ECDIS: Choosing the Proper
Secondary Positioning Source
D.Brčić,S.Kos&S.Žuškin
FacultyofMaritimeStudies,UniversityofRijeka,Rijeka,Croatia
ABSTRACT: The completion of ECDIS mandatory implementation period on‐board SOLAS vessels requires
certainoperational,functionalandeducationalgapingholestobesolved.Itespeciallyreferstopositioningand
itsredundancy,whichrepresentsfundamentalsafetyfactoron‐boardnavigatingvessels.Theproposedpa
per
deals with primary and secondary positioning used in ECDIS system. Standard positioning methods are
described, discussing possibilities of obtained positions’ automatic and manual implementation in ECDIS,
besidedefaultmethods.Withtheaimofemphasizingtheneedandimportanceofusingsecondarypositioning
sourceinECDIS,positioningissuefromthestandpointofend‐users waselaborated, representingapra
ctical
feedback of elaborated topic. The survey was conducted in the form of international questionnaire placed
among OOWs, ranging from apprentice officers to captains. The result answers and discussion regarding
(non)usageofsecondarypositioningsourcesinECDISwereanalysedandpresented.Answersandstatements
wereelab
oratedfocusingnotonlyinusageofthesecondarypositioningsysteminECDIS,butinnavigationin
general.Thestudyrevealedpotentialrisksarisingfromthelackofknowledgeandevennegligence.Thepaper
concludes with summary of findings related to discrepancies between theoretical background, good
seamanshippracticeandrealact
ionstakenbyOOWs.Furtherresearchactivitiesarepointedout,togetherwith
plannedpracticalactionsinraisingawarenessregardingnavigationwithECDIS.
http://www.transnav.eu
the International Journal
on Marine Navigation
and Safety of Sea Transportation
Volume 9
Number 3
September 2015
DOI:10.12716/1001.09.03.03
318
verification by comparing obtained positions with
other, independent methods and techniques. The
proposed paper deals with positioning in ECDIS
system and the usage of reliable secondary
positioningsource.Standardpositioningmethodsare
described along with their pros and cons, pointing
out the possibility of obtained positions’
implementation in ECDIS. Considering
common
navigationalpracticeandtheoreticalbackgroundfor
good seamanship, the positioning issue from the
standpointoftheend‐users,i.e.navigationalofficers
was elaborated. During the period of 2013‐2015 a
surveyintheformofinternationalquestionnairewas
placed among seafarers, ranging from apprentice
officers to captains. The questionnaire
contains
questions related to experience with ECDIS,
operation,personalopinionregardingjustificationof
ECDIS system as a primary navigation mean,
withdrawal of paper charts and other specific
problems with which OOWs, as skilled end‐users,
are facing with. Questions and answers regarding
ECDISpositioning were elaborated. The results and
discussion regarding
(non‐) usage of secondary
positioning in ECDIS were presented andanalysed.
Answers and statements were elaborated focusing
not only in using the secondary positioning in
ECDIS, but onnavigation in general.In this way, a
practicalfeedbackwasobtained,identifyingpotential
risksarisingfrom sequence of events in operational
navigation. The main causal process here is
transitional period of ECDIS implementation. The
paper concludes with summary of findings and
points out further research activities and practical
actions needed, aiming at safer navigation and
raisingsituationalawareness.
2 POSITIONING
This chapter gives an insight into positioning
methodsusednowadaysonboard
merchantvessels.
A short overview of traditional methods is also
presented, in order to emphasize the flow and the
significanceoftransitionperiod.Itrefersnotonlyto
positioning, but development of navigation tools,
navigation conduction in general and its
repercussions.
2.1 Generalconsiderations
Positioningcanbeclassifiedinorder
ofwhichtypeof
navigation takes place: ocean going, coastal,
navigation in port approaches and restricted
waterways,andnavigation inportareasandinland
waterways (Bowditch 2002, IMO A 860(20) 1997,
IMO MSC 915(22) 2001, Brčić et al. 2014). The
navigation type determines (available and proper)
positioning methods, positioning frequency
and the
required redundancy level. The most distinct
difference appears between ocean and coastal
navigation.Inopen‐seanavigation,theofficerofthe
watch (OOW) cannot rely on landmarks and shore
stations which are providing lines of positions
(LOPs)relativetomarkedobjects(Nav2013).Coastal
navigation therefore provides number
of reference
objects from which LOPs are derived, but also
represents greater risk for navigation (waterways,
restrictedpassageroutes,shallowwaters…).Inopen
sea,satellitepositioningisthemostcommonmethod,
also often and regularly employed in other
navigationsegments.
2.2 Anshortoverviewofpositioning
Depending on the type
of positioning source and
method used, position can be absolute
(unambiguous) and relative (related to an object),
employingdifferentcoordinate systems. On the one
hand, traditional positioning methods developed
overtime in pace withtechnology and navigational
equipment. On the other hand, the sole positioning
methodsremainedthesame,but
thenavigationtools
changed.Thepositioningprocessremains thesame.
New navigation methods are developing, becoming
moreaccurate,butalsomoresusceptibleatthesame
time.
Visual observations are the first and yet most
reliablepositioningandsituationalconfirmation.On
theopenseatheyarereferringonothervesselsinthe
first place, however in coastal navigation they are
consideredasthefundamentalwayfornavigational
situation interpretation and situational awareness.
The observed, orienteering directions from objects
aretakingformofbearings,andthechangingrateof
objects size gives an perception of distance to the
object. It determines two fundamental
lines of
position – the azimuth and the true distance (polar
coordinate system LOPs). These two positioning
toolsarenowadays usedin almost all methods and
navigational devices, becoming more refined with
navigationaldevelopment.
Figure1presentsatraditionalpositioningmethod
based on the moment of appearance or
disappearanceofthe
objectonthehorizon(Kosetal.
2010).Itseemsunlikelythatthismethodisstillused;
howeveritillustratesthehumaningenuityonetime
before, when visual observations were sufficient to
obtainareliableposition.
Figure1. Position determination based on the moment of
appearanceordisappearanceoftheobjectonthehorizon.
Thisrangingmethodisbasedonthecalculationof
thecurvatureoftheEarth,Earthradius (R) and the
usageofdirectionfinder,e.g.magneticcompass(Kos
etal.2010):
12 eo
ddd kh kh (1)
319
where d = distance to objectin (NM); h
e = height of
the eye of the observer; h
o = height of the observed
object; and k = constant calculated from the Earthʹs
mean radius and distance conversion in nautical
miles,k=1.9274.
Sincetheseahorizonisgreaterthangeometric,it
canbe stated thatk = 2. Thisleads to final distance
determination(Koset
al.2010):
2
eo
dhh (2)
Although aged, described positioning method
providesthenavigatorwithazimuth(directionline)
and distance (circle), the same lines of position on
whichcontemporarycoastalnavigationrelieson.
One of the first and sustained positioning
methodsis DeadReckoning(DR).In thismethod,a
knownposition is advanced on the
basis of vessel’s
course and distance prevailed regarding vessel’s
speed.Thismethodcanbeemployedalways,under
condition that there is one known position, known
course and known speed of the vessel. DR method
developed from manual plotting on navigational
charts to sophisticated methods embedded in
navigational devices, by employing various
differential and other algorithms. It can provide
reasonable accuracy, however it becomes fairly
inaccurate over time (Nav 2013). An Estimated
Position (EP) can be viewed as DR upgrade, where
outereffectson vessel’scourse and speed are taken
intoconsideration(e.g.setanddriftandotherleeway
effects), providing corrected
Course Over Ground
(COG) and Speed Over Ground (SOG) (Nav 2013,
Bowditch2002).
Celestial navigation positioning methods are not
reliantonanyelectronicsystems,andthepositionin
dueaccuracy(≤1NM)canbeobtainedbyusingthe
sextant, compass and nautical almanacsolely. Lines
ofposition(azimuthanddistances
again)arederived
by known locations and movements of celestial
bodies–stars,planets–whichareactingasreference
objects. Astronomical positioning methods are still
valid check in open sea navigation. However, with
the rise of new technologies and real‐time
positioning, there appears a possibility that these
methods
willslowlygointooblivion.Thenumberof
vessels where sextant is not anymore obliged
increases, distancing celestial navigation methods
fromthecommonusage.
Radar represents an enhanced eye of the
navigator, providing visibility in different parts of
the frequency spectrum. Vessel’s position can be
obtained in several ways. LOPs from
reference
objects can be derived thusmanually providing the
position.Inanautomatedway(EchoReference‐ER),
the reliable object in vessel’s vicinity can be used,
providingvessel’scontinuouspositionrelativetothe
object.Radarisautonomousdevice,meaningthat it
is not dependent on any other source except
electricity.
Even in the case of connected sources
failure (e.g. heading and speed sources) it can be
used with satisfying positional accuracy (e.g. in
RelativeMotionmodeandHeadUporiented).Radar
positioningisconfinedtocoastalnavigation,whilein
opensearemainsaprimarycollisionavoidancetool.
As for (and not
only) ocean navigation, satellite
positioning provides the navigator continuous
service of positioning, navigation and velocity
determination, as well as time standard service
provision (Parkinson & Spilker, Jr. 1996, IS‐GPS
2013). Among all GNSSs, the Global Positioning
System (GPS) is most used, fully operable system.
Satellitenavigation isembedded in
various systems
which are based on its services. In relevant
navigational equipment, such as Automatic
IdentificationSystem(AIS)andECDIS,GPSnotonly
provides its services, but acts as anintegrated part.
With the development of multi‐frequency satellite
receivers (either employing several dedicated
frequencies from one GNSS system, or employing
various GNSS system’s frequencies) and local and
global differential services, satellite positioning
services are reaching great levels of accuracy and
reliability; however they are, as any other system,
susceptible and vulnerable to effects of number of
externalcauses(Chapter5).
A number of supplementary positioning and
situationalmethodscanbe
usedinordertoobtaina
positionandinterpretnavigationalsituation.Someof
them can be used as direct positioning means (e.g.
InertialNavigationSystems,orhyperbolicnavigation
systems where available) while other are used as
complementary navigation tools (e.g. Echo
Sounders).
This short positioning overview was given in
order to
present the choices and possibilities OOW
canemployinordertoobtainaposition,butwhatis
more important, to provide the OOW with
supplementary positioning means in redundancy
terms. Emphasizing the need for secondary
positioning source, every position has to be double
checked or multi checked. Moreover, theoretical
knowledge
ofpositional erroranduncertainty areas
isessential.
3 ECDIS
ECDISsystemunitscanbedividedinhardwareand
softwarecomponents,uninterruptablepowersupply,
official/updated databases (electronic charts) and
required sensor ports formandatory and additional
navigation and aiding devices (IMO MSC 232(82)
2006, IMO A 817(19)1995). Thesedevices in
ECDIS
contextactasasensors,and they are not treated as
standalone devices anymore. This is important fact.
Once the regulated requirements are fulfilled
(SOLAS 1974, IMO MSC 232(82), IMO A 817(19),
IMOA694(17),IMOMSC191(79),IHOSPS‐662010,
IMO SN/Circ. 248), the system can
be ‘…accepted as
complying with the up‐to‐date chart’. This fact
determines further way of understanding and
conceptionofECDISasaprimary navigationmean,
butentailsnumberofconsequences.
3.1 Generalreview
According to (IMO MSC. 232(82), IMO A. 817(19)
1995) performance standards, at least three
mandatory devices
should be connected in ECDIS;
320
positioning,headingandspeedsource.Thesesensors
are needed for ECDIS to reach its full operability.
Today, those are (most commonly): satellite
navigation receiver (SNR) (ship’s position fixing
system,mainlyGPSreceiver),agyrocompass,anda
speed and distance measuring device, although
certainvariationsarepossible.Incaseof
twoormore
independent ECDIS systems on board vessels, at
leastone positioningsystemper ECDIS unit should
be provided (IMO MSC 232(82) 2006). Independent
ECDIS systems as a topic will not be elaborated
further, but other means of positional redundancy
insidesolesystem.
3.2 Positiondeterminationandtransfer
The
SNR GPS acts as an integrated part of the
system. It is embedded in the ECDIS as well as in
position interpretation on Electronic Navigational
Charts (ENCs), which are produced in the same
referenceframe(MSC232(82),NIMA2000,IHOSP‐
66 2010), providing continuous display of vessel’s
position.Inmost
ofECDISequipmentthereareother
dedicated sensor ports in order to connect other
positioningsources;second SNR orother. Here, the
most popular candidate is the Loran hyperbolic
system. Although these systems were abandoned
with the rise of satellite navigation, there are
indications that improved Loran (e‐Loran/e
‐Chayka)
willtakeplaceincreasingly.SeveralLoranchainsare
operating worldwide (NP282 2014). The reasons of
re‐commissioning of hyperbolic systems are either
positioning redundancy back‐up as well as security
reasons(Brčićetal.2014).However,theLoranglobal
networkisfarfromfullyoperational.
Besidesheading
(HDG)andspeedthroughwater
(STW) information, speed and distance measuring
equipment (SDME) and gyro compass data inputs
are enabling the DR automated position calculation
inECDIS.Inadditionwithexternalsensorswhichare
determiningvessel’sdrift,leewayandsteeringerrors
(Bowditch 2002) an EP positioning method is
enabled, improving
the DR technique. DR/EP
methodisquitereliableovershortperiods,andthey
have to be corrected regularly. However, this
implementationinECDIScanbepoor,dependingon
specific ECDIS manufacturer (Nav 2013, Norris
2010).
The position in ECDIS can be obtained and
maintainedrelativetoreferenceobjectsinthevessel’s
(restricted) vicinity, using the Echo Reference (ER)
method. It can be employed by using the radar
objects (overlaid on ENC), or by employing ECDIS
radar functions – Radar Integrated Board (RIB)
(Weintrit2009). Although more reliable than EP/DR
method, it suffers from several deficiencies: the
possibilityofselectionofproper
objectisnotalways
the case, and the time and the usage of reference
objectislimitedonthevicinitytothespecificobject,
i.e. vessel’s movement. Moreover, there appears the
possibilityofskippingbetweenobjects.
Anotherpossiblepositioningtechnique inECDIS
is a manual input of lines of positions (LOPs)
from
outer sources. It refers primarily on radar derived
LOPs.Sinceenteredmanually,LOPscanbederived
byallavailablenavigationalequipmentmeans.Thus,
any of methods providing desired lines of position
canbeused;howeveritishardlyeverthecase.
3.3 DisplayandplottingofpositionsonENCs
Current ECDIS systems are allowing for several
possibilities of plotting positions on the ENC. Once
predetermined, the positions are always present.
SNR GPS derived positions are continuously
displayedonchart.Byusingtrackoptions,theycan
alsobepresentedastrajectoriesshowingvessel’spast
movement. The same is possible with positions
obtained with the secondary positioning, whatever
the source. However, the secondary positioning
source option has to be defined in the system and
associated as the source which will provide the
positionandtrack.Thesystemwillalert theuserin
thecaseofpositioningsourceerrororunavailability.
However,if
theprimarypositioningsourcefails,and
thereisnosecondarypositioningsourcedefined,the
chart will freeze and it will become useless.
Dependingontheappearanceofsystem’salarm,the
timespanbetweenfailureandOOW’sawarenesscan
besignificant.Figure2presentsanexampleofENC
primary and secondary position
plots and
correspondingtracks.
Figure2.OwnshiptrackdisplaypresentedwithTransas©
Navi‐Sailor4000ECDISSystemonENCchart.Blackdotted
(straight) lines represent vessel’s position and past track
from the primary positioning source, with the secondary
positioningdisplaymarkedinblue.
Position from outer source can be plotted
manually in two ways:by using the manual option
(depending on the ECDIS model and function
availability), or by using predefined maps overlaid
onENC(additionallayers).Usually,thisfunctionis
oftenusedtoactuatetheusuallyinactiverasterchart
to a certain degree,
when ECDIS operates in Raster
ChartDisplaySystemMode(RCDS).
Sofar,fourpositiontypesarepossibletoploton
ENCs. Each of positions has its own accuracy and
uncertaintyareaandalevelofreliability.Thatiswhy
sole position is inadequate for safe navigation, and
the positioning redundancy
is essential. One has to
always check and compare as many positions from
varioussourcesasavailable.Moreover,thenavigator
hastoknowthereliabilityandperformanceofeach
positioningsourceandtheaccuracyonwhichhecan
count on, as well as to choose proper positioning
321
method depending on navigation type which is
takingplace.
To the date, positioning was defined clearly and
provenmethodshavebeenemployedovertheyears.
However, with the rise of paperless ships, the
navigation tools and, in a way, methods are
changing, becoming automated, implying certain
knowledgeadopted. It is
essentialtoensure thatall
operationalandfunctionalissueshavebeenclarified,
understoodandhandledproperly.Atthehalftimeof
the transitional period from paper charts to digital
cartography,theaimofthisresearchwastoreceivea
practicalfeedbackabouttheECDISpositioningtopic.
A survey has been
conducted asking answers from
truly engaged end‐users – navigational officers,
whichareexperiencingthetransitionalchange.
4 THESURVEY
The survey firstly emerged as questionnaire to
seafarers which are attending the Merchant Navy
Certification Courses at the Faculty of Maritime
Studies in Rijeka, Croatia. The aim of the
questionnaire was
the assignment of attendees in
ECDIS simulator working groups, depending on
their experience and familiarization level. The
questionnaire internationally spread on ECDIS
Courseattendeesinordertochoosetheproperlevel
ofexercises,besidesthoseregulatedwiththeECDIS
Model Course (IMO MC 1.27 2010). New questions
raisedinthe
questionnaire,regardingnotonlypure
ECDIS topic, but also general and specific
navigational questions. The final result (so far) was
the comprehensive survey, spread among
internationalshippingcompanies,achievingconcrete
opinions from navigational officers on global basis.
The survey yielded an international character,
comprising the period of 2013/2015. The initial
motivation
developed and became a wish for the
improvement – to gain an insight in current
knowledge not only on the good seamanship
behaviour,buttheresponseofseamenontransition
anditsreflectiononnavigationofficers.
4.1 Aquestionnaireoverview
Thequestionnaireisentitled:‘ECDISSurveyAnalyses:
Experience, Handling and
Opinion’, or ECDIS EHO.
Among total number of 24 questions, and besides
general questions (years of experience, rank…), the
followingquestionswereelaborated:
1 Does your job description include working with
ECDIS/ECSsystem?
2 In accordance with the SOLAS Convention and
the ECDIS mandatory regulations, what is the
currentstatus
onyourvessel?
Possessionofpapernavigationchartssolely;
Possession of one official ECDIS system and
appropriatefolioofpapercharts;
Possessionoftwoormoreindependentofficial
ECDIS system, meeting the requirements for
paperlessvessels;
Other________.
3 IstheECDISsystemusedasthe
primarymeansof
navigationonyourvessel?
4 In the system, do you use the setting related to
secondarypositioningsource?IfYES,pleasestate
whichone.
4.2 Therespondents
The questionnaire was targeted to seafarers for
whom the ECDIS term is not unfamiliar and the
usage of ECDIS is expected.
Thus, the profile of
respondentscomprisespresentandfuturenavigation
officersentirely. The Officers are affiliated to global
shippingcompanies,sailingonvesselsrangingfrom
DPOffshorevessels,largecruiserstomerchantnavy
vessels. The survey was completed by 123
participants: Captains (41), 1
st
Officers (30), 2
nd
Officers(24), 3
rd
Officers(5), Apprentice officers (5),
SeniorDynamicPositioning(SDPO)Officers(2),staff
captains(2)andundefinedrankings(14).
Undefinedrankingscompriseallofthementioned
ranks including harbour pilots, port captains and
port inspectors. The seamanship experience among
respondentsvariesbetween12monthsand41years.
4.3 Analysesandresults
Totalnumberof87ofrespondents(71%)isforminga
part of the navigational watch (Question No.1), or
theirworkdescriptionencompassesECDIShandling,
respectively.
AnswersregardingcurrentECDISstatusonboard
(QuestionNo.2)arepresentedinTable1.
Table 1. Summary of answers regarding current ECDIS
statusonboardvessels
_______________________________________________
InaccordancewiththeSOLASConventionandtheECDIS
mandatoryregulations,whatisthecurrentstatusonyour
vessel?
_______________________________________________
StatusNo.ofanswers
_______________________________________________
Paperchartsonly31
OneECDIS&ACF44
Paperlessrequirementsfulfilled19
Other29
_______________________________________________
TOTAL123
_______________________________________________
Inordertoachieveanswersfromofficerstowhom
the questionnaire was dedicated, the respondents
whichanswereda)(possessionofpaperchartsonly)
wereeliminatedfromfurtheranalyses.Theiranswers
willbediscussedlater.
Themostcommoncase(36%)wasthepossession
of one official ECDIS system and one Appropriate
Chart
Folio(ACF)(answerb).Asforoptionc),where
therewasnorequirementformandatorycarriageof
paper charts, the answers can be further divided in
two cases: i) Paper charts not required but present;
and ii) Truly paperless vessels with two or more
independent ECDISs. Looking at the
time span of
obtained and fulfilled questionnaires, the paperless
scenariobecomesmorecommonasthetimegoesby
and, as expected, paperless transition increasingly
takes place on board vessels. The Figure 3 shows
322
graphical presentation of noted scenarios regarding
ECDISandpaperchartscarriagerequirements.
Figure3.NotedscenariosregardingECDISstatusonboard
vessels.
The last possible answer (option d) refers to
specific cases on board vessels, where various
configurations were noted, mainly ECDIS as a
trainingsystemonly(‘nottobeusedfornavigation’);ECS
systems on board; RCDS system and ACF, unofficial
ECDIS on board, and ECDIS and RCDS
on board with
and/orwithoutACF.
Table2.summarizesanswerstoQuestion3.
Table 2. Summary of answers regarding ECDIS as a
primarynavigationmean
_______________________________________________
IstheECDISsystemusedastheprimarymeansof
navigationonyourvessel?
_______________________________________________
AnswerNo.ofanswers
_______________________________________________
Yes21
No71
_______________________________________________
TOTAL92
_______________________________________________
This question determines further quantity of
respondent numbers which will be additionally
elaborated.Thefinalquestion(QuestionNo.4):
In the ECDIS system, do you use the setting related to
secondary positioningsource? If YES, pleasestate which
one,
presents the backbone of the proposed research.
Answers were considered implying that
i) there is
ECDIS system present on board (omitting case a)
fromQuestionNo.2),ii)ECDISisusedasaprimary
navigationalmean,andiii)thereareseveralsystems
onboardincaseofpaperlessvessels.
Theanalysisexcludedseamennotformingpartof
the navigational watch (apprentice officers, port
captainsandpilots),which resultedintotalnumber
of 84 answers. The conditional respondents’ profile,
nowECDISoperatorssolely,ispresentedinTable3
andFigure4,respectively.
Table3.ProfileofrespondentsasECDISoperators
_______________________________________________
RankNumber
_______________________________________________
Master24
1
st
Officer24
2
nd
Officer23
3
rd
Officer5
StaffCaptain2
SDPO2
Undefined4
TOTAL84
_______________________________________________
Figure4.ProfileofrespondentsasECDISoperators.
Answers on Question 4 are summarized in
Table4.
Table4.SummaryofanswersregardingSPSusage
_______________________________________________
Inthesystem,doyouusethesettingrelatedtosecondary
positioningsource?IfYES,pleasestatewhichone.
_______________________________________________
SPSusageAnswer
_______________________________________________
Yes16
No42
N/A26
_______________________________________________
TOTAL84
_______________________________________________
The share of specific answers (Yes, No and Not
Applicable)isgraphicallyillustratedonFigure5.
Figure 5. Answers regarding the usage of the secondary
positioningsourceinECDIS.
Whenaskedwhichpositioningsourceisusedasa
secondary (implying affirmative answer),
respondents mostly (69%) answered GPS/DGPS
system. The remaining percentage refers to Dead
323
Reckoning(19%),orthecolumnremainedblank.As
for the N/A answer,itcan be interpreted in several
ways. One of the acceptable explanations is that
eitheri) the respondentsdidnot know the meaning
ofthe question (even ifSPS isused), or ii) theyleft
theblankcolumn
insteadofnegativeanswer.
In cases where ECDIS appears as a primary
navigation mean (19 in total), 7 respondents (37%)
are using the SPS option, for 1 respondent
(representing5%ofthetotalamount)thequestionis
notapplicable,and11respondentsdoesnotuseany
of the secondary positioning
options in the system,
making58%oftotalrespondentnumber.
5 DISCUSSION
InChapter2(Positioning)andChapter3(ECDIS),the
tendency was to emphasize the importance of
positioning redundancy in order to monitor the
primary position of the vessel. Several ways and
methods were presented. The possibilities of
positioning in ECDIS system were also described.
Theaimof theoretical backgroundoverview was to
emphasize the need and the possibilities of using
proper,reliablepositioningtechniqueasasecondary
positioning source in ECDIS system. Obtained
(simultaneous) positions willnever match perfectly,
however one (OOW) should know the uncertainty
area
ofeachpositionmethod,aswellaswhichfactors
areinfluencingtheaccuracyandreliabilityofderived
position.Again,itisessentialfortheOOWtoemploy
as far of the methods as he can (in due time). The
core question was: what is the proper replacement
for well‐known and
well‐used GPS? The question
wasplacedamongthenavigationalofficersasapart
ofthesurvey.
Considerable number of respondents (50%) does
notusethesecondarypositioningatall.Moreover,it
refers even to larger amount (58%) to respondents
whicharesailingonECDISapprovedvessels.Asfor
SPS
confirmative usage, it is frequently the satellite
navigationreceiver.
Here, drawing conclusions has to be made with
caution. Seamen who are sailing on non‐ECDIS
vessels, or the system is not yet familiar on board,
haveadifferentapproachandadifferentlookatthe
stated problem. In a way, it
can be considered as
normal. Traditional methods are implying
(simultaneous) combination of two or more
independentsystemsforobtainingposition,andthe
redundancy is covered in this way. However, with
the rise of ECDIS mandatory implementation and
paperlessvessels,significantissuescanoccur.There
appearstheriskthatthetransition
frompapercharts
and traditional navigation methods electronic
navigation means willfind the seamen unprepared.
Itspecificallyreferstoofficerswhicharenotfamiliar
withthesystemastheiryoungercolleagues(Weintrit
&Stawicky2008,IMOMC1.272010,Edmonds2007).
ArepresentativeofGNSSfamily,theGPSsystem,
is nowadays
taken for granted. According to
questionnaire results, respondents are using second
GPSreceiverasapositioningback‐up,amongthose
whoareusing SPSatall. Itisquitelogicalthattwo
SNRreceiverswillbeusedasprimaryandsecondary
positioning sources. However, whether it is about
two or
more GPS receivers, they are based on the
same positioning technique, meaning that they are
susceptibleand vulnerable to commonerror causes.
The same cause will degrade or disable all of the
receivers.
There appears proportionality between the
sophisticationlevelofprovidedservicesandsatellite
navigationsystems’sensitivitytoexternalinfluences.
It is particularly pronounced when navigational
equipment(ECDIS,AIS,LRIT)reliesanddependson
the same basic technology. As for GPS, the error
causecanbedividedintoanumberof components,
whose description would exceed the paper page
limit.Fromtheseanavigationcontext,theerrorscan
be divided
in three main categories: i) errors
resulting by natural causes, ii) those which are a
consequence of intentional interference and iii)
system errors related to integration characteristics
(e.g. Integrated Navigation System (INS) linkage
failures) (Kos et al. 2013, Norris 2010, Parkinson &
Spilker,Jr.1996).
GPS is not an autonomous system.
Its
functionality and performance depends on number
ofouterfactorsonwhichnavigatorhavenoinfluence
atall.Atcontrary,radarwillserveitspurposeeven
whennoouterdeviceisconnectedinit.Thatiswhy
radar presents a basic navigational aid in coastal
navigation, as well as in
collision avoidance. In
combinationwithECDIS,radaroverlayimageactsas
areliablesupplementontheENC;howeveritisnot
yetrecognizedassuch.
It is important to know and to be aware the
existence of all these possible error sources, to
mitigate them as much as possible, and if
not
possible, to find adequate (or any) replacement. At
theseever‐developingtimes,augmentingservicesare
increasingly present in sea navigation as well (e.g.
DGPSandSBASservices)(IMOMSC.114(73)2000).
The International Maritime Organization has
recognizedthepotentialofothersatellitenavigation
systemsbesides GPS (IMO MSC.379 (93)
2014, IMO
MSC.233 (82) 2006, IMO MSC.915 (22) 2001, IMO
MSC.113(73)2000,IMOA.860(20)1997),aswellas
the usage of combined satellite receivers onboard
vessels (IMO MSC.115 (73) 2000). It leads to
improvement of integrity and reliance, but also to
complacency. It is important in this, still initial
transitional stage, to know and to be aware of
potential risks and dangers. And that is the gist of
proposed research: to mitigate lack of knowledge
with proper actions, and to ease in most efficient
manner the forthcoming changes. As Dr. Andy
Norris wrote in his book (Norris 2008): ‘…in
future
integratednavigationsystems, GPSs and gyro‐compasses
willbeonlyblackboxeshiddensomewhereintheinterior
of the bridge’. This statement says a lot, but also
impliesalot.Satellitenavigationsystemsbecamean
inevitablepartofnavigationalbridges.Thenavigator
does not have to employ old, slow
positioning
methods,giventhat he has final,perfect, continuous
positionplotonthechartscreen.Ordoeshe?
The conducted survey initiated number of
unwritten questions. Several issues were identified,
andtheycanbesummarizedasfollows:
324
Non‐usage of ECDIS secondary positioning
source,
Over‐relianceontechnology,and
Issuesarisingfromtransitionperiod.
Taking identified issues in consideration, an
unwanted sequence of events can appear.
Transitional issues (paper‐ to paperless) and
improper usage of the ECDIS system (presented on
theSPSexample)can
giverisetoeventsandactions
withunwantedmanifestation.Lackofeducationand
practice appears as a main reason for ignorance.
Indifferenceappears as a continuation of ignorance,
however here the problem has already seriously
increased. In combination with human vanity and
negligence, the sequence can lead to operational
errors,
developmentofunwantedevents andfinally
to real accidents occurrence. The ever‐present over‐
relianceontechnologyandoperationalsystemsonly
enhancesthisflowandweightstherisks(Figure6).
Figure6.Sequenceofunwantedevents.
Severalinvestigationandresearchreports(MAIB
2012, BSU 2011, BEMAER 2010, BSU 2009, MAIB
2009, NTSB 2007a, NTSB 2007b, Žuškin et al. 2013)
demonstrated the share of ECDIS and its
inappropriateusageinmarineaccidents, actingasa
direct or indirect cause. The good seamanship and
navigationalpracticemaynotbe
doubted;howeverit
isthetransitionissueforwhatitcountsfor.
In order to prevent described events (the
unwantedmodel–Figure6),thereappearsaneedfor
concrete actions. By proper handling of vertical
components of the model (identified issues)
horizontal chain ofcomponents canbe mitigated to
certain extent, and even eliminated. However, it
requires fundamental and comprehensive actions to
betaken,byengagingdifferentlevelsofactivities.
Theactivitiesshouldreflectonexistingproblems,
developing problems and possible problems which
can arise in the future, but which also can be
predicted. In order to close this problem
circle,
severallevelsofactivitieshavetobeemployed:
1 Educationalactivities,byteaching(regularclasses),
courses (STCW and other specifications) and
discussions with seafarers, raising awareness on
the basis of gained knowledge. In this way, the
problemscanbedetectedintheirbeginning;
2 Practicalactivities,supplementforeducation,
taken
by using available resources as navigational
simulators,trainingvessels,etc.
3 Research activities, with the aim of preventing
problemsandmaintainingthisstate.Itisprobably
thehardestlevel.Itcomprisesthoroughresearch,
monitoring, surveys among end‐users, marine
accident investigations and analyses, and other
feedback methods, implying continuous
bidirectional
communication.
The final outcome will, of course, depend on
individualperson.However,inaproposedwaythe
learning model achieve the required level of
situational awareness, if looking at such delicate
topic. The cornerstone of the model is proper
educationanditspracticalconfirmation.
6 CONCLUSION
Theproposed paper deals
with usage on secondary
positioning inside the ECDIS system, during the
beginning of the second half on ECDIS mandatory
implementation period. A survey was conducted
aimingatinsightgainincurrentsituationon board
vessels regarding positioning topic, but also
navigationconductingingeneral.Theanswersfrom
allnavigational rankswere
analysed anddiscussed.
Thefindingsindicatedthatthesecondarypositioning
source is not used as it should be, what entails
potentialrisksregardingsafetyofnavigation.Asthe
transitionperiodpasses,unsolvedproblemswillonly
riseintheirnature. Paperchartswillnotdisappear,
howeverthenumberofpaperlessECDIS
vesselswill
increase. It requires proper actions to be taken on
differenteducational,practicalandpreventinglevels,
ingeneralaswellasinsubtlemeans.
The ECDIS EHO survey does not end with this
paper. The proposed research presents the basis for
further work and described activities. As for the
survey,
itcomprisesallofthem.Thesurveyisnotthe
researchinwhole:itactsasapartofit.Thelargerthe
future sample of respondents, the more the
questionnaire is possibleto extend, and to focus on
arisingproblems,whichinthiswaycanbedetected
intheir
roots.Thesameappliestoeducation,courses
and discussions. This will determine further
modification of the survey. Furthermore, different
levels of problems can be identified: existing
problems,thosewhicharecurrentlydevelopingand
problemswhichwillappearinthe(near)future.
The question remains: what is the proper
secondarypositioningsource
whichhastobeusedin
ECDISsystem?
325
Thekeyansweristhepropereducationandgood
seamanship. It is not anything new; however it
requires thorough and complex actions to obtain it,
asfor anyadoptiontonewconceptsandsituations.
Aiming to reach a satisfying state of awareness,
nothingismoreeffectivethanwhenaperson
realizes
the gravity of the problem alone. And the proper
path for recognizing it comes exclusively and only
withone’sknowledge.Notother’sknowledge,butits
own.
ACKNOWLEDGEMENTS
The presented research was conducted within the
projectentitledResearchintotheCorrelationofMaritime
Transport Elements in Maritime Traffic: Satellite
navigation
segment, supported by the University of
Rijeka,RepublicofCroatia.
Student assistants with the affiliation to the
Faculty of Maritime Studies of University of Rijeka,
Croatia,JosipMohovićandDavidĐurićdeservethe
praisefortheirassistanceinsurveypreparation.
TheauthorsaregratefultoalltheOfficers ofthe
navigational watch on their time and they
willingnessforfulfillmentofthequestionnaire.Their
answershaveanimmensesignificance.
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