Historical values (heading, position and speed) are continuously recorded and processed:
•
ROT value is calculated from historical values of the heading
•
Acceleration of the ROT is calculated from the same set of values
•
Acceleration of the speed is calculated from STW values.
•
The PP (Pivot point) of the ship is calculated from GPS positions, speed and heading
values
•
The future positions are calculated by iteration (every second) as follow:
- Last position
- Last heading, ROT and speed
- Time interval
•
The new position of the PP is calculated from the above values, and the ship’s orientation
is displayed according to the new heading (Last heading re ROT applied for the
time interval within the limit of ROT and time to reach the ROT).
Active leg window
This option is designed to help mariners during navigation in narrow waters where precise
following along the planned route is essential.
The ship’s shape is displayed in the middle of the window together with the active leg and
turning curves using a scale from 3500 – 10000 depending on the ship’s dimensions.
The picture is leg bearing oriented. In the top left and right corners of the window, current
leg bearing and next leg bearing are displayed.
In the bottom part of the window, XTD value is displayed. An indicator is displaying the
direction where to go following the exact route.
In case of ship turning, this value is calculated for the end of turn showing how far away from
the leg the ship will end its turn for the next leg.
Moving along the leg
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Predictor
| ECDIS900 Operator Manual