Self-Compensation Procedure - ADVANSEA COMPAS S400 Manuel Utilisateur

8.2- Self-compensation procedure

To successfully self-compensate, you must navigate:
- On a flat and powerless sea.
- Far from large magnetic masses such as cargo ships.
- In an open area to make a circle whose diameter is about 4 times the
boat length.
- With a constant speed of the order of 3 or 4 knots so as to obtain a travel
time of the circle in about one minute
During compensation, the boat is expected to circle at a constant
speed, clockwise. The boat must travel between 390 and 400 ° at least,
with a constant speed of gyration.
The user must have the boat describe a circle with a diameter equal
to 4 times the length of the boat. It is obvious that the more time to
complete the self-compensation round will be, the best the calibration will
be. But in practice, it will also be more difficult to ensure a constant rate
of gyration over a longer period.
The compensation is calculated with a resolution of 0.25 °, the
correction value being coded on a byte, will be between -32.0 ° and +
31.75 °. 36 compensation points are calculated, one point every 10 °. An
interpolation is performed between the 2 values closest to the table. When
calculating, the angle is obtained at 1 / 10th of a degree.
The calibration procedure can be started after the first 30 seconds
after power-up by connecting the initialization wire (green wire to ground).
You can cancel a calibration at any time by disconnecting this initialization
wire.
The advanSea Compass then emits the proprietary $ PADVH frame
in addition to standard frames $HCHDG and $HCHDM:
$HCHDG,58.8,,,,*77<CR><LF>
$HCHDM,58.8,M*1C<CR><LF>
$PADVH,58.8,0,5,*55<CR><LF>
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