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Simrad GC80/85 Compact MK2 Gyro Compass
Note!
988-12718-003
when the vessel is in harbor. If there is any significant difference
between the displayed value and the vessel's actual latitude, the
value should be adjusted according to
input source
, page 63.
When GYRO is selected as latitude input source and MANUAL is selected
as the speed input source, the indicated latitude value will not be updated
and hence an error may occur.
Speed
The GC80/85 Gyro compasses calculate bearing based on the speed and
latitude information that is input to the Gyro as speed source. Any error in
speed input will therefore cause incorrect true bearing.
Press the DISP button until the vessel's speed information is displayed.
Confirm every 4
hour that the displayed speed is the same as the vessel's
th
actual speed.
Any discrepancy between displayed speed and actual speed is corrected as
described in
If GYRO is selected
you need to verify that GPS connection is set to Non in
extension menu A-2, 2.9.G.
Setting the Speed input source, page 64.
Speed error correction
All Gyro compasses will generate a heading error caused by the vessel's
speed and earth rotation. GC80/85 calculates this error based on latitude
and speed input information, and automatically corrects the bearing signal
output. If no speed information is available, the Gyro compass will output a
heading error either westwards or eastwards depending on the vessel's
course.
If speed information is unavailable, the figure on the next page may be
used to manually calculate the heading error.
In this figure, the following values are used as examples:
-
Latitude:
-
Vessel speed:
-
Vessel heading:
The heading error is found by:
1
Drawing a line between the latitude and the vessel's heading
(shown with gray line in the figure).
2
Drawing a straight line (broken line in the figure) between the
vessel's speed and the point where the latitude/heading line
intersects with the solid black line in the figure.
In the example above, the figure shows a speed error of appr. 1.1° and the
true bearing should then be 30°-1.1° = 28.9°.
Setting the Latitude
40°
16 knots
30°
26
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