User's Manual

Table Of Contents
ED 3100 G 110 / 02 (2011-10)
Operating Instructions
A-7 Target Handling
A RADAR.fm / 10.11.11
A-63
NACOS Platinum
Prerequisites for the Collision Avoidance Computation in case of AIS Targets
The collision avoidance computation can be performed only if the relative speed between own ship and
the target is known. This must be determined from the speed vector over ground (COG, SOG) received
from the AIS target and from the own speed vector over ground. The own speed vector over ground is
mainly determined from the Bottom Track data of the selected speed sensor; otherwise, it is deter-
mined with the aid of the COG/SOG of the selected position sensor.
If an AIS target is not transmitting COG and SOG, no collision avoidance computation takes place for this
target. Therefore, the target cannot be acquired automatically. If it is already being tracked, no
Dangerous Target alarm occurs in the case of a dangerous approach. The symbol of this AIS target is
displayed dashed.
If, because of missing data or caused by sensor selection, the own speed vector over ground cannot be
determined, then for all AIS targets the collision avoidance computation and the Dangerous Target
alarm does not take place. The symbols of all AIS targets are then displayed dashed. Three minutes after
the occurrence of this situation, the AIS No CPA Alarm, SOG Lost alarm appears