5-47 
 
z  If the gain, sea clutter suppression, rain/snow clutter 
suppression are not adjusted adequately, the lost 
target alarm may be easily generated. So such 
adjustments should be very carefully. 
Lost Target Alarm 
 
 
 
 
 
 
 
 
 
 
 
 
 
When it is impossible to continue tracking any acquired and tracked target, or the data of AIS target cannot 
received for a specified time, the    Lost    alarm will be generated. The typical causes for alarm generation are 
shown below, but not limited to the following:   
•  The target echo is very weak. 
•  The target is shadowed by a shore or a large ship and its echo is not received. 
•  The target echo is blurred by sea clutter returns. 
If a target under tracking goes into a range of 32 nm and can no longer be tracked, it is canceled without a lost 
target alarm being issued.   
 
Lost Target Alarm 
 
Status  Symbol on display  Alarm characters  Alarm sound  Conditions 
Lost target 
 
 
 
 
 
 
 
 
 
 
 
Red Blinking 
Lost 
Beep sound (pee) 
Alarm 
acknowledgeable
 
The alarm will sound once 
when a lost target symbol is 
displayed. 
 
System Function Alarm (TT Data) 
 
If occurring some failure in input signals or the processor circuits, generate an alarm. If generating an alarm in 
the target tracking function, 
TT(Data) is displayed in the alarm indication (located at the lower right of the 
display) and nothing is displayed in the indication of the target tracking information. Its cause is inferred that 
the target tracking circuit is malfunctioned, and then ask our agent or brunch office to repair it. 
 
System Function Alarm 
 
Alarm characters  Alarm sound  Condition 
 
TT(Data) 
 
Beep sound 
(pi-pi-pi) 
If the target tracking circuit has some abnormal 
condition, this alarm generates. 
 
Attention
12 
AIS12