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4. AIS OPERATION
4-14
[AIS LOST FILTER]
1 BACK
2 MAX RANGE
OFF/ON
0NM
4 MIN SHIP SPEED
OFF/ON
0.1kn
5 EXCEPT CLASS B
OFF/ON
5 MIN SHIP LENGTH
OFF/ON
0M
4.10 Lost Target
A target is declared a lost target when it fails to produce data for six minutes or
five reporting intervals, whichever is the shorter. When this occurs, the target is
marked with the (flashing) lost target symbol and the indication "LOST" appears
in the Alert Box. To acknowledge a lost target, press the [ALARM ACK] key, or
use the trackball to select the ALARM ACK box then push the left button.
Lost target
Note 1: If a TT lost target mark is displayed when the [ALARM ACK] key is
pressed (or the ALARM ACK box is clicked) to acknowledge an AIS lost
target, the TT lost target also is erased.
Note 2: The AIS data transmission interval depends on target’s speed. For
example, the data is transmitted every 10 seconds on ship speed of 0 to
14 knots and every two seconds on the ship speed of more than 23
knots. For details see the owner’s manual of the AIS.
4.10.1 Lost target filter
If there are a lot of AIS targets in your area, the lost target alarm may sound
frequently. In this case you may wish to have the alarm ignore lost targets whose
range, speed, class or length are below the threshold value you specify.
1. Left-click the MENU box to open the menu.
2. Select 4 [TT
●
AIS] to open the TT
.
AIS menu.
3. Select 8 [AIS LOST FILTER].
AIS LOST FILTER menu