JRC JMA-993-SA Instruction Manual page 57

a a o o a a o a a a o o a a a a a a a a a a a a a a o a a a a a a a a a a a a
Vo: O\rm ship's speed
0 o: Own ship's course
Vr:Other ship's lrue speed
Vr: Other ship's reative speed
I r: Olher ship's tue couse
6
":
Other ship s realive couse
0 A:Asp€ct
Fi9.1.21 Relative Vector and True Vector
Radarand Gollision Avoidancg'''''
r' r'' r'''''''
r''
Radar is still playing an important roll for collision prevention and positioning. A plotter is
used to further enhance the radar functionality. The plotter is capable of plotting other
positions of other ships in 3 to 6 minute intervals to monitor their movements. The plots
of other ships represent their tracks relative to own ship, and it is shown whether there
is a there is a risk of collision, namely CPA and TCPA can be obtained. This method
using a plotter is fairly effective, but the number of target ships, which are manually
plotted, is limited and it takes several minutes to measure those
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