Appendix E: Connecting a Raytheon Active Compass
E-5
Calibrating the ST80 Active Compass
The Raytheon ST80 active (fluxgate) compass must be calibrated to ensure the
transmitted heading data is accurate. You should calibrate the compass before it
is used as a navigational aid.
Calibration comprises two procedures:
•
Heading Alignment:
This is required to match the displayed heading to a
known heading or transit.You can align the active compass with your ship’s
magnetic steering compass, providing your ship’s compass is accurate. You
should use a minimum of 4 cardinal points
•
Compass Linearization
: This detects heading errors caused by metal
objects, such as engines or gas bottles. Once such errors have been detected,
the compass corrects them automatically.
D4125-1
000˚
0˚
W
E
090˚
180˚
Uncorrected
Linearised
Aligned
270˚
360˚
Heading Alignment
1. Mount the compass (as described in the handbook supplied with it) so the
alignment marker points forward and is parallel to the centreline of your
vessel. Secure in position
2. On your 10" CRT radar display, ensure the Heading data box is displayed.
Use your ship’s steering compass to align your vessel to four point at 90°
intervals; ideally you should use the four cardinal points.
Note the headings displayed on your radar display and the ships compass
for each point.
3. Note the error in the active compass heading for each point and average the
error. To obtain the least error in the active compass, deduct the average
error from each heading reading. The table below shows an example of
corrected heading data.
Appendix F:
Connecting an
Active Compass
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