NORTHROP GRUMMAN Sperry Marine NAVIGAT X MK 2, Assembly Instructions Manual

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NAVIGAT X Mk 2 056341 Rev. AA
5: Installation Page 5-5
5.4.1 Alignment Error Correction
In order to obtain correct heading data, the existing alignment error (i.e. the an-
gular difference between the compass orientation and the vessel's fore-and-aft
axis) must be determined and the required correction applied. Alignment error
is 0° if the sides of the compass housing run exactly parallel to the vessel‘s lon-
gitudinal axis and the back of the housing points dead ahead. The alignment er-
ror correction is carried out electronically by setting the required correction
value in the Service Setup 1 (code 600).
To carry out the alignment error correction:
1) Determine the existing alignment error by comparing the compass head-
ing with the vessel's true heading. The true heading must be known to an
accuracy of at least 0.5°.
compass orientation
vessel's fore-and-aft axis
alignment error
Caution
The compass must have been in continuous operation for at least 4 hours be-
fore the alignment error can be determined accurately.
If bearing repeaters are used to determine the true heading, these must be
properly aligned to the vessel's fore-and-aft axis.
2) In the Service Setup 1 (code 600), select the align error correction sub-
menu.
3) Enter the required correction value.
The correction value equals the alignment
error with the sign reversed.
Example:
The vessel's true heading is 123.0°,
the compass displays 123.4°,
the alignment error is therefore 0.4°;
thus, the required correction value is -0.4°.
The correction range is -179.9–180.0°.
ALIGN ERROR CORR.
SERVICE SETUP
+000.0°
Note
After correction of the alignment error, the compass is to display the vessel's
true heading to an accuracy of at least 0.5°.