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6.3 Orientation of the GNSS and Signature
Next
align the ‘Heading’ and the GNSS direction. The heading, measured by the GNSS, is the actual, true
north, direction that the a
ntenna is pointing at. The direction as indicated under the ‘Global Navigation
Satellite System’ label is the direction in which the ship moves, relative to earth. When adjusting this it is
important that the vessel is moving in a straight line, preferably straight into or with the local current. If the
current (or strong wind) is coming in from the side, the vessel will drift sideways which will give an incorrect
direction of movement. To adjust the offset, open the ‘Configuration’ and adjust the ‘Heading Offset’. The
correction will be applied immediately after pressing ‘Enter’ or ‘Tab’.
Don’t forget to click ‘Save Configuration’ !
The Bottom track velocity and direction are measured relative to earth by the Signature. The GNSS velocity
and direction should match. In the example shown in the status screen this is not the case. This also shows
up very clearly in the track plot. The blue line shows the track according to the GNSS, the red line according
to the b
ottom tracking. It’s clear that the bottom track direction is about 45 degrees off, which is due to the
45 degrees offset of the Signature sensor.
These values should match
