Samyung ENC SI-30A, Manual Instruction

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3 9
PROGRAM UPLOAD SCREEN
3-11
The explanation signs of AIS
This equipment of AIS shows 4 different signs and each sign has functions as below.
: The sign for the pausing ship
: The sign for the moving ship
: The sign when you choose a ship.
: The sign for the ship which is in danger
The meaning of signs show as below
COG/SOG : It means Course of ground, Speed of Ground.
Heading : It means the azimuth of vessel’s head.
Direction of turn : It means that the ship’s direction.
In the event of signing (4) case, it distinguishes dangerous ship after considering CPA/TCPA.
CPA/TCPA means as follow
CPA(Closest Point to Approach)
TCPA(Time for Closest Point Approach)
t
3
t
3
t
2
t
2
t
1
t
1
Target
Target Target
Target
10 knot 10 knot 10 knot 10 knot
O wn
O wn O wn
O wn
5 knot 5 knot 5 knot 5 knot
You get the distance each time between 2 points while the ship(Own) and the other
ship(Target) cruise with 5Knot, 10 Knot as the picture above. When the time should be t1, t2,
t3, …, tn, if you get the distance, you can learn that t3 is the closest point. At that moment,
the point should be CPA and the time when it arrives at T3, should be TCPA.