User's Manual

5.5 ALARM DISPLAY
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CPA / TCPA Alarm
In the system, targets are categorized into two types: tracked / activate AIS targets and dangerous targets.
The grade of danger can easily be recognized on the display at a glance. So the officer can easily decide which
target he should pay attention to.
The types of target and alarm are shown below.
CPA / TCPA Alarm
Status Symbol on display Alarm characters Alarm sound Conditions
Dangerous target
Red blinking
CPA / TCPA
Beep sound
(pee-poh)
Alarm
acknowledgeable
• CPA ≤ CPA LIMIT,
• 0 ≤ TCPA ≤ TCPA LIMIT
An alarm is issued when all the
conditions are met.
The AIS targets that issues
alarm refer to Section 5.1.5
“Setting Collision Decision
Criteria (CPA/TCPA Limit)”.
CPA Limit and TCPA Limit: The Setting Values
12
AIS12
Since these alarms may include some errors
depending on the target tracking conditions, the
navigation officer himself should make the final
decision for ship operations such as collision
avoidance.
Making the final navigation decision based only
on the alarm may cause accidents such as
collisions.
Caution