4. AIS OPERATION
4-8
4.12
CPA and TCPA Alarm
When the predicted CPA of any ARP/AIS target becomes smaller than a preset CPA alarm range
or its predicted TCPA less than a preset TCPA alarm limit, an audio alarm sounds and the symbol
of the offending AIS target changes to the dangerous target symbol.
Dangerous target symbol
You may silence the audio alarm with the
CANCEL/HL OFF
key. The flashing of the symbol con-
tinues until you intentionally terminate tracking of the target. The ARP continuously monitors the
predicted range at the Closest Point of Approach (CPA) and predicted time to CPA (TCPA) of
each AIS target.
This feature helps alert you to targets which may be on a collision course with own ship. However,
it is important that GAIN, SEA, RAIN and other radar controls are properly adjusted.
1. Press the
MENU
key to open the menu.
2. Choose Target and then press the
ENTER
key.
3. Choose CPA and then press the
ENTER
key.
4. Choose appropriate time and then press the
ENTER
key.
5. Choose TCPA and then press the
ENTER
key.
6. Choose appropriate TCPA and then press the
ENTER
key.
7. Press the
MENU
key to close the menu.
Triangle is thicker
than that of active
target
Off
0.5nm
1nm
2nm
3nm
5nm
6nm
30sec
1min
2min
3min
4min
5min
6min
12min
