1.1 The radar equipment is intended for installation
in high speed craft (HSC) with the following characteristics:
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.1 a maximum speed of 70 knots;
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.2 a maximum rate of turn 20°/s; and
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.3 normally operate between latitudes 70°N
and 70°S.
1.2 In addition to the general requirements contained
in Resolution A.694(17), the radar equipment should comply with the
following minimum performance requirements.
The radar equipment should provide an indication, in relation
to the craft, of the position of other surface craft and obstructions
and of buoys, shorelines and navigational marks in a manner which
will assist in navigation and in avoiding collision.
The operational requirement, where the radar antenna is
mounted 7.5 m above sea level, is that the equipment should give a
clear indication of surface objects such as a navigational buoy having
an effective echoing area of approximately 10 m2 at 2.5
nautical miles in the absence of clutter.
The surface objects specified in 3 should be clearly displayed
form a minimum range of 35 m up to a range of one nautical mile, without
changing the setting of controls other than the range selector.
5.1 The equipment should, without external magnification,
provide a multi-colour daylight display with an effective radar picture
diameter of not less than 250 mm.
5.2 Day and night colours should be provided;
it should be possible to adjust brightness.
5.3 The equipment should provide the following
set of range scales of display:
0.25, 0.5, 0.75, 1.5, 3, 6, 12 and 24 nautical miles
5.4 Additional range scales may be provided.
5.5 The range scales displayed and, when in use,
the distance between range rings should be clearly indicated.
5.6 Off-centre facilities should be provided of
at least a minimum of 50% and not more than 75% of range scale in
use.
6.1 Fixed electronic range rings should be provided
for range measurements as follows
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.1 on the range scales of 0.25, 0.5 and 0.75 nautical
miles at least two range rings; and
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.2 on all other range scales six range rings should
be provided.
6.2 A variable electronic range marker should
be provided with a numeric readout of range.
6.3 The fixed range rings and the variable range
marker should enable the range of an object to be measured with an
error not exceeding 1% of the maximum range of the scale in use, or
30 m, whichever is the greater.
6.4 It should be possible to vary the brilliance
of the fixed range rings and the variable marker and to remove them
completely from the display.
7.1 The heading of the craft should be indicated
by a line on the display with a maximum error not greater than ±1°.
The thickness of the display heading should not be greater than 0.5°
measured at maximum range at the edge of the screen.
7.2 Provision should be made to switch off the
heading indicator by a device which cannot be left in the heading
marker off position.
8.1 Provision should be made to obtain quickly
the bearing of any object whose echo appears on the display.
8.2 The means provided for obtaining bearing should
enable the bearing of a target whose echo appears at the edge of the
display to be measured with an accuracy of ±1° or better.
8.3 A minimum of two lines for parallel indexing
should be available
9.1 The equipment should be capable of displaying
as separate indications on a range scale of 1 nautical mile or less,
two 10 m2targets in the absence of sea clutter at a range
of between 50% and 100% of the range scale in use, and on the same
azimuth, separated by not more than 35 m in range.
9.2 The equipment should be capable of displaying
as separate indications two (10 m2) targets both situated
at the same range between 50% and 100% of 1 mile range, on the 1.5
mile range scale and separated by not more than 2.5° for X band
radars and 4° for S band radars.
The performance of the equipment should be such that when
the craft is rolling and pitching up to ±10° the range
performance requirements of 3 and 4 continue to be met.
The scan should be clockwise, continuous and automatic through
360° of azimuth. The scan rate should not be less than 40 revolutions
per minute. The equipment should operate satisfactorily in relative
wind speeds of up to 100 knots.
12.1 Means should be provided to enable the display
to be stabilized in azimuth by an approved directional sensor. The
equipment should be provided with an approved directional sensor input
to enable it to be stabilized in azimuth. The accuracy of alignment
with the approved directional sensor transmission should be within
0.5° with a rate of turn of 20°/s.
12.2 The equipment should operate satisfactorily
in the unstabilized mode when the main approved directional sensor
is inoperative.
Means should be available, while the equipment is used operationally,
to determine readily significant drop in performance relative to calibration
standard established at the time of installation, and that the equipment
is correctly tuned in the absence of targets.
Suitable means should be provided for the suppression of
unwanted echoes, i.e. from sea clutter, rain and other forms of precipitation,
clouds and sandstorms. It should be possible to adjust manually and
continuously the anti-clutter controls.
15.1 The equipment should be capable of being
switched on and operated from the place at which the navigator operates
the high speed craft.
15.2 Operator controls should be accessible and
easy to identify and use. Where symbols are used they should comply
with the recommendation of the Organization on symbols for control
on marine navigational radar equipment.
15.3 After switching from cold, the system should
be operational within 4 min.
15.4 A standby condition should be provided from
which the equipment can be brought to an operational condition within
15 s.
After installation and adjustment on board, the bearing
accuracy as prescribed in these performance standards should be maintained
without further adjustment irrespective of the movement of the craft
in the earth's magnetic field.
17.1 The equipment should be capable of operating
in relative and true motion.
17.2 The radar origin should be capable of being
off-set at least 50% and not more than 75% of the radius of the display.
17.3 Where sea or ground stabilization is provided,
the accuracy and discrimination of the display should be at least
equivalent to that required by these performance standards.
18.1 The design of the antenna system should enable
it to be installed in such a manner that the operational efficiency
of the radar system as a whole is not substantially impaired.
18.2 The antenna system should be so designed
as to withstand the forces expected to be experienced by such craft.
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Operational with Radar Beacons
19.1 All radars operating in the 3 cm band should
be capable of operating in a horizontally polarized mode.
19.2 It should be possible to switch off those
signal processing facilities which might prevent a radar beacon from
being shown on the radar display.
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Multiple Radar Installations
Where two radar installations are required to be carried,
they should be so installed that each radar can be operated individually
and both can be operated independently.
21.1 The radar system should be capable of receiving
information from equipment such as gyro-compass, speed and distance
measurement equipment (SDME) and electronic position-fixing systems
(EPFS) in accordance with international standards.footnote
21.2 The radar should provide an indication when
any input from an external sensor is absent. The radar should also
repeat any alarms on status messages concerning the quality of the
input data from its external sensors which may influence its operation.
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Navigational Information
The radar display should be capable of presenting in graphical
form positions and navigational track lines, e.g. way-points and tracks
between way-points in addition to the radar information. The source
of the graphical information should be clearly indicated.
Target trails should be displayed by the radar echoes of
targets in the form of synthetic afterglow. The trails may be either
relative or true. The true trails may be sea or ground stabilized.