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THE SIMPLIFIED ARPA OPERATION
The simplified Automatic Radar Plotting Aids (ARPA) function is designed to help prevent a collision with other
vessels or landmasses.
The radar automatically acquires and plots other vessels and landmasses that are in the set watch area. It
automatically calculates the closest point of approach (CPA), and the time to closest point of approach (TCPA)
limit of your vessel and the targets, and sounds an alarm if there is a danger of colliding with them.
ARPA Features
• Only targets in the 0.25 to 16 NM range that are displayed with a high luminosity (strong return signal) can be
selected as ARPA targets.
• Up to 10 targets can be acquired and plotted on the screen, including up to 5 automatically acquired targets
(when the Auto Acquire function (p.25) is turned ON in the Menu screen).
• Plot positions are identified by an approved symbol mark
(p. 24) and associated plot number.
• The target and vector line will move across the screen at the rate and direction defined by the calculated true or
relative course and speed.
• The vector line is displayed on the target.
■
ARPA operation
D
Operation
Select a target on the screen that you want to track.
1. Move the cross-line cursor onto a desired target.
2. Push [ACQ]/[
] to set the target for tracking.
•A dotted circle symbol is displayed on the cursor.
•After 1 minute progressing time has passed, the circle
changes to a solid circle with a dotted vector line, the
number of the target is displayed beside the icon, and
tracking operation starts.
•When the target disappears, a red cross blinks on the
target, and then the mark disappears after 1 minute.
•When a target advances within the CPA and TCPA
limits, the mark changes its color to red, blinks, and
sounds an alarm. To cancel the alarm, push [CLEAR]/
[
].
3. To display a target information, move the cross-
line cursor onto the target, and then push
[ENTER]/[
].
•The corners of a square is displayed on the selected
target.
•
The target identification number,
position, course
(CRS), speed (SPD), CPA, TCPA, bearing (BRG), and
distance (DIST) are displayed.
4. To release the target, move the cursor onto the
target, then hold down [CLEAR]/[
] for 1
second.
Target
ARPA
icon
