5.2    TT OPERATION 
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5.2.6    Reference Target (Reference) 
 
This equipment can  calculate and  display the  speed of own  ship by  tracking a  target whose position is fixed 
with respect to the ground and by setting this target as a reference target. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
z  The reference target function is to be used if the own ship's 
speed cannot be displayed normally due to trouble such as a 
speed sensor malfunction. Do not use the reference target 
function except in emergencies. 
z  If the speed or course of the own ship is changed or a new 
reference target is set, the displayed speed may take 3 minutes 
or more to reach the specified speed after the speed / course 
change or the setting. 
Even after 3 minutes or more has passed, the speed may differ 
from the specified speed depending on the tracking condition. 
z  If a large radar echo such as a land target is set as a reference 
target, the vectors of the speed and other tracking targets will 
not be displayed correctly and may cause an accident. 
z  If a sailing ship is set as a reference target, the vectors of the 
speed and other tracking targets will not be displayed correctly 
and may cause an accident. 
z  If the    REF.    is selected for the speed sensor, the AIS function 
cannot be turned on. 
z  If the reference target is lost or the target tracking function is 
stopped, the speed sensor is placed in manual mode    MAN . 
z  The loss of a reference target may have a major impact on the 
accuracy of the results for true speed and true course of the 
target and that own speed will be degraded. 
z  The reference targets are only used for the calculation of true 
speed. 
Attention