Simrad HS50 - Manual (Page 39)

INSTALLATION
20221081 / F
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Run mode: Used for switching the HS50 between
NORMAL and DEMO mode.
DEMO mode is used for simulating input data
to the system.
WARNING! The HS50 must not be switched to DEMO mode when
the system is in operation!
Log data, Server address, User name and Password:
Used for service purpose.
Caution! A change in Expert setup parameters (except Head offset and
Alarm sound) will not take effect before the HS50 is restarted.
Heading offset
The Head offset feature allows you to correct for a constant
compass heading offset that may be present as a result of an off
axis misalignment between the Sensor unit and the vessel
alongships axis.
Note! It is important that the Sensor unit is mounted accurately in the
alongships direction so the Head offset value does not exceed
±5°. If the mounting orientation is not within these tolerances
the heading accuracy will be degraded. Instead of exceeding a
Head offset value of ±5° the Sensor unit orientation should be
adjusted mechanically.
The system has to be calibrated on board the vessel after
installation. A typical calibration consists of calibrating the
direction of GPS antennas within the Sensor unit against an
external reference. Type of reference must be decided according
to the required accuracy. Alternative references for calibrating
the heading offset of the Sensor unit could be:
• The heading of the pier or quay the vessel is moored to.
• An external compass reading like from a gyro compass.
• Two fixed points on the chart that the vessel is sailing
between.
The observation period for the heading difference should
continue for an as long as possible period in order to eliminate
errors in the HS50 measurements caused by multipath effects.
These may be particularly pronounced in the static conditions of
a harbor area.