This section should give a short
introduction to operational aspects of a
is functions and features human aspects
the AIS transponders unit is designed to
automatically broadcast the vessels
position course and speed over ground
together with static and voyage related
information after activation an
automatic built-in integrity test or bi
T is performed in case of malfunction an
alarm is given and the unit should stop
transmitting all day is units are
designed to communicate with each other
automatically exchanging information
about course and speed and intended
route
this enables the Mariner to be aware of
other ships long before visual contact
is established allowing appropriate
action to be taken in good time
the master shall keep a is an operation
at all times except where international
agreements rules or standards provide
for the protection of navigational
information if the master decides to
switch off the a is this should be
logged in the ship's log book 200w
should periodically check that the
information transmitted by the AIS is
correct the information transmitted by
AIS can be divided into three main
groups static dynamic and voyage related
in addition safety related messages
could be transmitted when needed the
static information provided by AIS is
set on installation and consists of the
following own ship data maritime mobile
service identity
msi call sign and name IM own number
ships length and beam type of ship and
location of positioning fixing antenna
the dynamic information except
navigational status is automatically
updated by a is the dynamic data may
consist of the following parameters
ship's position with accuracy indication
and integrity status position timestamp
in Universal Time coordinated UTC course
over ground speed over ground ships
heading navigational status and rate of
turn the voyage related data must be
manually entered into the system from
the operators panel and may consist of
the following parameters ships draft
type of cargo destination an estimated
time of arrival ETA root plan and short
safety related messages the technical
status of the AIS is checked
automatically by the built-in integrity
test vit but the quality or accuracy of
the ship sensor data input to the AIS is
not checked by the bi T before being
transmitted to other ships and short
stations the officer on watch
oooww should therefore carry out regular
routine checks during the voyage to
validate the accuracy of the information
being transmitted the frequency of those
checks needs to be increased in coastal
waters a is information can be displayed
in various ways such as minimum display
as alpha numeric information only or any
other suitable device such as radar
activist arpa etc these symbols are
recommended by the international
maritime organization IMO for use with
the graphical presentation and display
of a is target data in standalone or
integrated navigational systems the
symbols may be changed at a later stage
after experience has been gained a
sleeping target symbol indicates the
presence and orientation of a vessel
equipped with a is at a given location
no additional information is presented
until activated thus avoiding
information overload this symbol
represents automatic or manual
activation of a sleeping target for the
display of additional graphically
presented information including a vector
speed and course over ground the heading
and rate of turn our OT or direction of
turn indication if available to display
actually initiated course changes this
symbol represents the manual selection
of Nea is target for the display of
detailed information in a separate data
display area in this area received
target data as well as the calculated
cpa and TCPA values will be shown the
dangerous target symbol represents an
AIS target activated or not and
indicates which data contravene preset
cpa and/or TCPA limits the lost target
symbol represents the last valid
position of an AIS target at the time
data ceased being received the AIS
symbols shall be similar to that
provided by arpa or radar as far as
practical when a is information is made
available for a graphical display at
least the following information should
be displayed position course over ground
speed over ground heading rate of turn
or direction of turn as available
whenever the graphical display of a is
targets is enabled the graphical
properties of other target vectors
should be equivalent to those of the AIS
target symbols otherwise the type of
vector presentation radar plotting
symbols or a is symbols may be selected
by the operator the active display boat
should be indicated the presentation of
a is target symbols except for sleeping
or lost targets should have priority
over other target presentations within
the display area including targets from
electronic plotting aide TBA automatic
tracking aid a TA or art by if such a
target is marked for data display the
existence of some other source of target
data may be indicated and the related
data may be available for display upon
operator command a common reference
should be used for the superimposition
of a is symbols with other information
on the same display and for the
calculation of target properties such as
TCP a CPA if a is information is
graphically displayed on radar the
equipment should be capable of
approximately stabilizing the radar
image and the AIS information if a is
information is graphically displayed on
radar the equipment should be capable of
appropriately stabilizing the radar
image and the AIS information target
data derived from radar and AIS should
be clearly distinguishable as such and
the mode of presentation should be
indicated when the display of a is
symbols is enabled removing a dangerous
target should only be possible
temporarily as long as the operator
activates the corresponding control if
the course over ground co ji
and speed over ground sog vector is
shown its reference point should be
either the actual or the virtual
position of the antenna if zones guard
rings or search areas for automatic
acquisition are specified and activated
these should be the same for all targets
regardless of their source whenever the
calculated cpa and TCPA values of an AIS
target fall below the set limits a
dangerous target simple should be
displayed and an alarm should be given
the preset cpa or TCPA limits applied to
target data derived from different
sensors should be identical if the
signal of a dangerous a is target is not
received within a specified time frame a
lost target symbol should appear at the
last known position together with an
alarm the lost target simple should
disappear after the alarm has been
acknowledged an automatic display
selection function may be provided to
avoid the presentation of to target
symbols for the same physical target if
target data from a is and from radar
plotting functions are available then
the activated a is target symbol should
be presented if the automatic selection
criteria are fulfilled
otherwise the respective simple should
be displayed separate the operator
should have the option to make
reasonable changes to the default
parameters of automatic selection
criteria as far as practical the user
interface for operating displaying and
indicating a is functions should be
equivalent to the other relevant
functions of the navigational aid
current ship
bridges with all their communication
navigation and other equipment represent
a major challenge to the navigator the
risk of information overload is imminent
which is why many navigators question
the value of the minimum keyboard and
display type a is the solution to this a
is problem seems to be a graphical
presentation of the AIS target data