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JMA-9172-SA Instruction Manual > 5.OPERATION OF TARGET TRACKING AND AIS > 5.1  PREPARATION
If the mode is ground stabilization, SOG/COG used for own ship's information in 
target tracking. If the mode is sea stabilization, SPD (speed through the water) / 
HDG (heading) used for own ship's information in target tracking.
AIS (Automatic Identification System) function
The AIS function shows the target’s information on the radar display, using other 
ship's information sent out from the AIS unit.
5.1.1 Collision Avoidance
5.1.1.1 Problems of Collision Avoidance in Navigation
Marine collision avoidance is one of the problems that have been recognized from 
of old. Now, it will be described briefly who the collision avoidance is positioned 
among the navigational aid problems.
The navigation pattern of all mobile craft constitutes a system with some closed 
loops regardless of the media through which the mobile craft travels, whether air, 
water, the boundary between air and water, or space.  This pattern consists of two 
closed loops in principle, one of which is a collision with another mobile craft and 
the other is a loop of finding a right and safe way to reach a predeterminate 
destination. Fig. 5-1 shows the conceptual diagram of navigation pattern by MR. 
E.W. Anderson. The closed loop of collision avoidance is shown on the left side 
and the closed loop of finding a right course on the right side.
Fig 5-1: Navigation Pattern