3. TARGET TRACKING (TT)
3-21
3.15
Collision Alarm (CPA, TCPA)
This radar calculates CPA and TCPA by using own ship and relative target positions.
The TT continuously monitors the pre-
dicted range at the Closest Point of Ap-
proach (CPA) and predicted time to
CPA (TCPA) of each TT. When the
predicted CPA of any TT becomes
smaller than a preset CPA range and
its predicted TCPA less than a preset
TCPA limit, the audio alarm sounds
and "TT DANGER OF COLLISION"
appears (in red, flashing) in the Alert
Box. In addition, the symbol of the of-
fending TT is red and flashes together with its vector.
This feature, when used correctly, helps prevent the risk of collision by alerting you to
threatening targets. It is important that GAIN, A/C SEA, A/C RAIN and other radar con-
trols are properly adjusted.
CPA and TCPA ranges must be set up properly taking into consideration the size, ton-
nage, speed, turning performance and other characteristics of own ship.
The reference point for CPA and TCPA calculation can be selected from antenna po-
sition or conning position. For further details, see section 1.50.
3.15.1
How to set the CPA and TCPA ranges
CPA and TCPA ranges can be adjusted from the ap-
propriate indication in the [TT] box.
1. Left-click the [CPA/TCPA] indication to activate
the feature.
2. Place the cursor on the indication you wish to
adjust.
3. Left-click, or spin the scrollwheel, to adjust the settings as required. The settings
options are outlined in the table below.
3.15.2
How to acknowledge the TT collision alarm
Press the
ALARM ACK
key on the control unit, or select the [ALERT] box with the
trackball then left-click to acknowledge the alarm and silence the buzzer. The alert "TT
DANGER OF COLLISION" remains in the Alert Box until the dangerous situation is
gone or you intentionally terminate target tracking. The symbol and vector stop flash-
ing and are displayed in a solid red color.
Indication
Method
Settings options
CPA
Left-click
0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 5.0, 6.0 (NM)
Scrollwheel
0.1 to 20; 0 to 10 in 0.1 NM increments, 1 NM increments thereafter
TCPA
Left-click
1, 2, 3, 4, 5, 6, 12, 15 (minutes)
Scrollwheel
1 to 60 minutes in 1-minute increments
CAUTION
CPA/TCPA Alarm
The CPA and TCPA alarm feature should
never be relied upon as the sole means for
detecting the risk of collision.The navigator
is not relieved of the responsibility to keep
visual lookout for avoiding collisions,
whether or not the radar or other plotting
aid is in use.
CPA setting
TCPA setting
Left-click here to activate
CPA/TCPA settings.
Summary of Contents for FAR-2218
Page 132: ...1 OPERATIONAL OVERVIEW 1 110 This page is intentionally left blank ...
Page 176: ...3 TARGET TRACKING TT 3 36 This page is intentionally left blank ...
Page 202: ...4 AIS OPERATION 4 26 This page is intentionally left blank ...
Page 232: ...5 VIDEO PLOTTER OPERATION 5 30 This page is intentionally left blank ...
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