5-23  Section 5 Basic Operation of the Radar 
 
 
 
APP A 
APP B 
 
 
5.4.9  Displaying other ship’s trails (Trails) 
Other ships’ movements and speeds can be monitored from the lengths and directions of their trails, 
serving for collision avoidance.   
 
 
5.4.9.1  Trails motion mode 
There are two types of trails: relative motion trail and true motion trail. 
Relative motion trail:  The system plots the trails of a target at a position relative to the own ship. 
  The operator can easily judge whether the target is approaching the own 
ship. 
  While the own ship is moving, the system also plots the trails of land and 
other fixed targets. 
True motion trail:    The system plots the absolute motion trails of a target, irrespective of the 
own ship’s position. 
  The operator can easily judge the course and speed of the target. 
  The system does not plot the trails of land and other fixed targets. 
 
 
While the true motion trail mode is active, this equipment enables the continuous use of true motion 
trail even if any of the following operations is performed: 
•  Motion mode change (TM/RM) 
•  TM reset 
•  Azimuth mode change 
•  Off Centre 
 
Accurate true bearing signals  and  speed signals are necessary for using the true motion trail 
mode.