International Journal
on Marine Navigation
and Safety of Sea Transportation
Volume 1
Number 2
June 2007
The Role of Navigational Aids Such as
Radar/ARPA, ECDIS, AIS, Autopilot, on Safe
Navigation at Sea
H. Yousefi
Chabahar Maritime University, Iran
ABSTRACT: Chabahar Maritime University has started radar/ARPA simulator training course since 2004 and
the training has been carried out fully comply with STCW95 Convention and the IMO model course.
According to the improvement in navigational technology, the reducion of Navigational Aids as two credits of
the latest BSc sylabus for future officers on board ships will be discussed through this article in depth.
In addition to the above, the author attempts to describe the AIS (Auomatic Identification System) which is
defined by IMO and has been adopted by the latest revision of SOLAS chapter V. In fact, the AIS is part of
ship’s radio station and is surveyed together with radio installation. The AIS training is going to be taken
place from next semester at Chabahar Maritime University in order to improve the skill of the trainees in order
to rely the information provided by AIS..
Based on Section A-1/2 of STCW95 Convention,
training of marine simulator regarding Radar and
ARPA Courses are compulsory for future officers
and masters on board ships. According to the above
sction of STCW95 Convention, the following factors
should be consideed:
be suitable or the selected objectives and training
tasks and be capable of satisfying the specific
assessment objectives;
be capable of simulating the operating cababi-
lities of shipboard eqipment concrned, to the level
of physical realism appropriate to tranng of
assessment objectives, and include the
capabilities, initiations and possible erroe of such
have sufficient behavioural realism to allow
a trainee to acquire and a candidate to exibit the
skills appropriate to the training and assessment
provide a contolled opearating environment,
capable of producing a vriety of conditions,
which may include mergency, hazardos or
unusual situations relavant to the training and
assessment objectives;
provide an interface through which a trainee can
interact with the equipment, the simulated
environment and, as appropriate, the instructor;
present an instructor, and assessor the ability to
control, monitor and record exercises for the
effective debriefing of trainees and effective
assessment of the performance of candidates.
In addition to the above essential simulator
training items, instructors and assessors should
consider some more factors in order to assess the
ability of candidates based on his/her competancey
AIS is abbrivated as Automatic Identification
System which is being used to concur with the IMO
standards (MSc74,(69), annex3). Indeed, IMO
reccomended that it is compulsory for all vessels to
be equipped with AIS until July 2008. As Cap.Holder
said that we might discover that AIS could have a
positive or ngeative influence on collissions. Its
impact will be positive if it aids mutual recognition,
enhances the application of the correct rules and
proides unambiguous agreement of further action. It
will also be posiive if AIS can identify ships in
clutter or hidden behind bends.
In fact, AIS offers the following information
which can be categorized as three main group: a).
Constant information suach as name of ship, IMO
no, length and breath of ship, type of ship.b). Voyage
information such as draft, type of loaded cargo,
destination and ETA, etc. c). Changed information
such as time, compase course, position, ship speed,
sailing condition, etc.
David Patraiko pointed out that wihin a decade,
ships could have to fit VDRs, AIS and increasingly
ECDIS, wih a proliferation of different designs for
similar equipment.
In the meantime, Cap. EM.Scott stated that
...there are significant risks associated with the
introductin of AIS and regulators must resolve
uncertainty through practical research to evaluate
optimum displays.... therefore, seafarers can use AIS
guideline book which has been issued by IALA in
order to get following information:
1 Receiving information related to the AIS radar
targets that have been sent by local VTS.
2 Maximum 12 courses and way points with the
reccomended turning circle which are presented
by VTS.
3 Information regarding metorology, oceanography,
direction & velocity of wind, sea temperature, air
temperature, direction and speed of current, depth
of water, etc.
4 Navigational information such as crossing,
overtaking, head on situation, etc.
5 Reigonal or local information for safe navigation
at coastal waters.
According to the new amendment of SOLAS
(no.19), ECDIS became a compulsory navigational
aids on board ships. The advantages of the system is
to save time for applying correction and a large
space as chartroom in the bridge. Peter Jones from
UK Hydrographic Office stated that... the emergency
of electronic publications with their additional
functionality and potential for more efficient
updating may assist in enhancing access to the full
range of relevant navigational information.
ECDIS can be used as an optimum equipment in
order to save all the ship’s courses, turning and
maneouvaring, etc. By installing ECDIS system,
moden technology, to all vessels; it may cause to
enhance safety at sea and improve seafarers
operational capability while sailing. Of course,
adoption of IMO regulations by all countries will
cause to provide clean, secure and safe sea. As
Andrew Hal as seafarer concluded in his presented
paper tha... I have no doubt that the increased use of
electronic charting can only improve safety and
efficiency of navigation.
It is essential to know that what is meant by GPS?
The system consists of three operational segments
such as a). Ground station tracking / processing
network b). Space based constellation of trans-
mitting satellites c). User segment consisting of GPS
navigation receivers. Ground station is controlled by
department of Defence of the United states and the
earth stations track the GPS satellites and the
information transmitted to each satellite every six
The space satellites consists of 27 operational
satellites which are distributed in six polar orbits and
located at an altitude of 20000 km above the earth’s
The receiver on the earh’s surface allows to see at
least four and max 12 satellites simultaneously with
10 degree elevation, it will be either a military
Precise Positioning Service (PPS) or civilian
Standard Positioning Service (SPS) unit. The GPS
receiver measures the time for a signal transmitted
by the satellite and multiplied by the velocity of light
in order to calculate latitude, longitude and height.
It should be noted that since the clock of the GPS
receiver is not synchronised with the satellite clock,
therefore to avoide of receiving large position errors
it is arranged to observe four or more satellites at the
same time. In 1980, the intenational surveying
companies offer Differential GPS (DGPS) with all
the capability of GPS plus better positioning
accuracy of +/_3 to 5 metres. The principle
configuration of DGPS is that by arranging one or
more GPS receiver as fixed reference stations in
order to measure ranges to all satellites in view; and
also calculate all the errors in the signals by DGPS
corredition processor then the DGPS corrections are
transmitted via the Inmarsat A,B or M compatible
marine satellite communications network.
DGPS service improves vessel safety for
navigating in confined waters or even as
hydrographic surveying or offshore construction
vessels and so on.
VDR or Vessel Data Recorded is used for recording
ship voyage information; it is called black box too
which is introduced based on the advanced
technology in shipping. The advantages of this
equipment is as follows:
1 Main Recording Unit (MRU) can record the
required information of IMO and shipowner up to
24 hours.
2 Voyage information capsule or main black box of
ship which is located at the heighest point of ship;
is can save the required IMO information up to
12 hours.
3 Electrical power of the equipment is supplied by
linking the system to the emergency power of
ships with a 2 hours battery.
4 The required information of the IMO for
passenger sips are as follows: date, time, latitude
and longitude, ship speed, ship course,
communication of perssonal at the bridge and
VHF, radar information, depth of water, ship
engines, velocity and direction of wind, alarm
system, etc.
Although, the technology of marine radars is under
progress, neverthless the latest technology of the
radars is going to be considered through this paper.
There is no any modification in the megnetron
system and the scanner of marine radars. Referring
to the new design of marine radars, radar display unit
of CRT has been changed LCD system. Based on
advanced technology, marine radars integrated wih
AIS which is quite important equipment in order to
prevent collision cases at sea.
The combination of the above two systems
require some corrections to be applied to the new
type of radards; for instance whether a marine radar
should be able to detect mountain and rock in 20
miles distance toward the land. Inded, a marine radar
must easily find the emergency signals from SART,
Racon, Beacon, etc and be able to detect small radar
targets in critical situations.
Concerning to the significance of marine radards,
Mike Pope (2002) concluded that ... I belive radar
will continue to play an important, if not crutical,
role in safety at sea. Even with the advent of high
accuray DGPS and AIS, radar will continue to be a
primary aid to navigation and collision avoidance.
Improvement in technology making new navi-
gational equipment to be become more complicated
for user or seafarers. Therefore, reducion of
Navigational Aids as two credits in the latest BSc
sylabus is not suitable for future officers on board
ships. It means that more emphasise should be taken
to improve safety of navigation. Use of advanced
equipment on board ships is not the solution for safe
navigation at sea; the qualify of training of new
navigational tools is vital for navigators which
should be considered by the nautical colleges.
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