2 Training and assessment in radar observation
and plotting should:
3 Demonstrations of and practice in radar
observation should be undertaken, where appropriate, on live marine radar
equipment, including the use of simulators. Plotting exercises should
preferably be undertaken in real time, in order to increase trainees’
awareness of the hazards of the improper use of radar data and improve their
plotting techniques to a standard of radar plotting commensurate with that
necessary for the safe execution of collision-avoidance manoeuvring under
actual seagoing conditions.
General
Factors affecting performance and accuracy
4 An elementary understanding should be
attained of the principles of radar, together with a full practical
knowledge of:
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.1 range and bearing measurement,
characteristics of the radar set which determine the quality of the
radar display, radar antennae, polar diagrams, the effects of power
radiated in directions outside the main beam, a non-technical
description of the radar system, including variations in the features
encountered in different types of radar set, performance monitors and
equipment factors which affect maximum and minimum detection ranges
and accuracy of information;
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.2 the current marine radar performance
specification adopted by the Organizationfootnote;
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.3 the effects of the siting of the radar
antenna, shadow sectors and arcs of reduced sensitivity, false echoes,
effects of antenna height on detection ranges and of siting radar
units and storing spares near magnetic compasses, including magnetic
safe distances; and
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.4 radiation hazards and safety
precautions to be taken in the vicinity of antennae and open
waveguides.
Detection of misrepresentation of information, including false echoes and
sea returns
5 A knowledge of the limitations to target
detection is essential, to enable the observer to estimate the dangers of
failure to detect targets. The following factors should be emphasized:
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.1 performance standard of the
equipment;
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.2 brilliance, gain and video processor
control settings;
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.3 radar horizon;
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.4 size, shape, aspect and composition of
targets;
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.5 effects of the motion of the ship in a
seaway;
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.6 propagation conditions;
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.7 meteorological conditions; sea clutter
and rain clutter;
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.8 anti-clutter control settings;
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.9 shadow sectors; and
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.10 radar-to-radar interference.
6 A knowledge should be attained of factors
which might lead to faulty interpretation, including false echoes, effects
of nearby pylons and large structures, effects of power lines crossing
rivers and estuaries, echoes from distant targets occurring on second or
later traces.
7 A knowledge should be attained of aids to
interpretation, including corner reflectors and radar beacons; detection and
recognition of land targets; the effects of topographical features; effects
of pulse length and beam width; radar-conspicuous and -inconspicuous
targets; factors which affect the echo strength from targets.
Practice
Setting up and maintaining displays
8 A knowledge should be attained of:
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.1 the various types of radar display
mode; unstabilized ship’s-head-up relative motion; ship’s-head-up,
course-up and north-up stabilized relative motion and true motion;
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.2 the effects of errors on the accuracy
of information displayed; effects of transmitting compass errors on
stabilized and true-motion displays; effects of transmitting log
errors on a true-motion display; and the effects of inaccurate manual
speed settings on a true-motion display;
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.3 methods of detecting inaccurate speed
settings on true-motion controls; the effects of receiver noise
limiting the ability to display weak echo returns, and the effects of
saturation by receiver noise, etc.; the adjustment of operational
controls; criteria which indicate optimum points of adjustment; the
importance of proper adjustment sequence, and the effects of
maladjusted controls; the detection of maladjustments and corrections
of:
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.4 the dangers of using radar equipment
with maladjusted controls; and
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.5 the need for frequent regular checking
of performance, and the relationship of the performance indicator to
the range performance of the radar set.
Range and bearing
9 A knowledge should be attained of:
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.1 the methods of measuring ranges; fixed
range markers and variable range markers;
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.2 the accuracy of each method and the
relative accuracy of the different methods;
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.3 how range data are displayed; ranges
at stated intervals, digital counter and graduated scale;
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.4 the methods of measuring bearings;
rotatable cursor on transparent disc covering the display, electronic
bearing cursor and other methods;
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.5 bearing accuracy and inaccuracies
caused by parallax, heading marker displacement, centre
maladjustment;
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.6 how bearing data are displayed;
graduated scale and digital counter; and
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.7 the need for regular checking of the
accuracy of ranges and bearings, methods of checking for inaccuracies
and correcting or allowing for inaccuracies.
Plotting techniques and
relative-motion concepts
10 Practice should be provided in manual
plotting techniques, including the use of reflection plotters, with the
objective of establishing a thorough understanding of the interrelated
motion between own ship and other ships, including the effects of
manoeuvring to avoid collision. At the preliminary stages of this training,
simple plotting exercises should be designed to establish a sound
appreciation of plotting geometry and relative-motion concepts. The degree
of complexity of exercises should increase throughout the training course
until the trainee has mastered all aspects of the subject. Competence can
best be enhanced by exposing the trainee to real-time exercises performed on
a simulator or using other effective means.
Identification of critical echoes
11 A thorough understanding should be attained
of:
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.1 position fixing by radar from land
targets and sea marks;
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.2 the accuracy of position fixing by
ranges and by bearings;
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.3 the importance of cross-checking the
accuracy of radar against other navigational aids; and
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.4 the value of recording ranges and
bearings at frequent, regular intervals when using radar as an aid to
collision avoidance.
Course and speed of other ships
12 A thorough understanding should be attained
of:
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.1 the different methods by which course
and speed of other ships can be obtained from recorded ranges and
bearings, including:
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.2 the relationship between visual and
radar observations, including detail and the accuracy of estimates of
course and speed of other ships, and the detection of changes in
movements of other ships.
Time and distance of closest approach of crossing, meeting or overtaking
ships
13 A thorough understanding should be attained
of:
Detecting course and speed changes of other ships
14 A thorough understanding should be attained
of:
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.1 the effects of changes of course
and/or speed by other ships on their tracks across the display;
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.2 the delay between change of course or
speed and detection of that change; and
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.3 the hazards of small changes as
compared with substantial changes of course or speed in relation to
rate and accuracy of detection.
Effects of changes in own ship’s course or speed or both
15 A thorough understanding of the effects on a
relative-motion display of own ship’s movements, and the effects of other
ships’ movements and the advantages of compass stabilization of a relative
display.
16 In respect of true-motion displays, a
thorough understanding should be attained of:
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.1 the effects of inaccuracies of:
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.2 the effects of changes in course or
speed or both by own ship on tracks of other ships on the display;
and
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.3 the relationship of speed to frequency
of observations.
Application of the International Regulations for Preventing Collisions at
Sea, 1972, as amended
17 A thorough understanding should be attained
of the relationship of the International Regulations for Preventing Collisions at Sea, 1972,
as amended to the use of radar, including:
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.1 action to avoid collision, dangers of
assumptions made on inadequate information and the hazards of small
alterations of course or speed;
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.2 the advantages of safe speed when
using radar to avoid collision;
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.3 the relationship of speed to closest
approach distance and time and to the manoeuvring characteristics of
various types of ships;
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.4 the importance of radar observation
reports and radar reporting procedures being well defined;
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.5 the use of radar in clear weather, to
obtain an appreciation of its capabilities and limitations, compare
radar and visual observations and obtain an assessment of the relative
accuracy of information;
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.6 the need for early use of radar in
clear weather at night and when there are indications that visibility
may deteriorate;
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.7 comparison of features displayed by
radar with charted features; and
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.8 comparison of the effects of
differences between range scales.