Smiths Kelvin Hughes Nucleus 3 5000 Series, Системный справочник

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Past His tory
52 Target Past History can be displayed by selecting
[PAST POSn] from the radar menus next to the radar
display and pressing any pushbutton to select ON. From the
selection time onwards, the four past positions, separated by
a period of two minutes are displayed for every target which
is being tracked.
NOTE:
A823 has variable history.
53
Past History information is True in True Motion TM(T)
and Relative Motion RM(T) modes and Relative in
Relative Motion RM(R) mode.
GUARD ZONES
54
Two Guard Zones are available, one Fixed and the
other Variable, each zone is preset to 0.5nm wide.
Fixed Zone
55
The Fixed guard zone is preset at 5.5nm to 6.0nm.
56 To activate the Fixed and Variable guard zones,
select
[GUARD] in the [PLOT] menu and press any
pushbutton, the Fixed guard zone appears on the screen at
5.5nm to 6.0nm. The Variable guard zone appears on the
screen at 7 nm to 7.5 nm and can be adjusted from 1.25nm
to 40nm. The pop-down box allows selection of the zones
‘Active’ or ‘Switched Off’.
NOTE:
(1) Turning the Fixed Guard Zone off automatically
removes the Variable Guard Zone.
(2) Targets acquired and tracked when the Guard Zone was
activated, continue to be tracked when the Guard Zone is
switched off.
Vari able Zone
57 Activation of the Variable guard zone is automatic
when the Fixed guard zone is turned on. The variable
zone cannot be displayed alone without also displaying the
fixed zone.
58
The Variable guard zone can be positioned to any
range from 1.25nm out to 40nm.
59 To change the Variable guard zone range, move the
trackerball to anywhere on the zone (not at the ends)
and press the [Select] pushbutton. Movement of the
trackerball then changes the range. Pressing [Select] again
fixes the new range.
Bear ing Limits
60 The port and starboard bearing limits of both the Fixed
and Variable guard zones default to 45° relative to
Ownship’s.
61 To change the bearing limits select the [PLOT] menu
and [GUARD] function. Move the trackerball to the
either end of the guard ring that is to be adjusted (i.e. port or
starboard) and press the
[Select] pushbutton. Move the
trackerball to increase or decrease the angle, Minimum port
limit 15° Maximum starboard limit 180° from ship’s head.
Press
[Select] pushbutton to enter the new value. To
de-activate a guard ring press [Select] , position the
trackerball anywhere on the ring and then press the
right-hand pushbutton.
NOTE:
The fixed ring can only be selected at its ends.
ARPA ALARMS
62
ARPA Alarms, listed below, are displayed in a RED
highlighted box on the right-hand side of the screen. If
the ARPA computer is not available the following message is
displayed:
63
With the ARPA functioning, warnings produce an
audible alarm and the following alarm messages may
be displayed in the highlighted box:
(1)
W h e n a t a r g e t i s
within both CPA and TCPA, a flashing symbol is
generated on the target.
(2)
When a target is lost
this message appears and is always shown until
the target is deleted.
(3)
If a target is not seen
for eight consecutive scans the target is counted
as weak and the Lost Target symbol appears in
the last vector position. If the target is of interest,
after a further 10 sweeps the target is designated
as ‘Lost’ and an Acknowledge box appears above
the warning box.
(4)
W h e n a t a r g e t
enters a Mute Sector it is automatically deleted
and this message is displayed.
KH 2020
Chap 2b
July 03 2b.8 Amdt 5
CD-2078
THE ARPA
COMPUTER HAS NOT
BEEN FITTED
Collision Warning
Weak echo Search
Lost Target
TARGET DELETED
IN MUTE SECTOR