Kongsberg Simrad MF90, Installation Manual

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Example procedure
It is not within the scope of this publication to provide detailed instructions for dimensional
surveying. However, an example procedure is provided to help you understand how it is
done.
Prerequisites
For accurate ship dimensions you need the detailed vessel drawings. You need a printed
version of each drawing. Each drawing must be to scale.
Procedure
1 Define the location of the
origin in the coordinate
system.
The origin is the common
reference point where all
three axis in the vessel
coordinate system meet.
All physical locations of
the vessel’s sensors (radar
and positioning system
antennas, echo sounder and
sonar transducers, motion reference units, etc.) are referenced to the origin. In most
cases, the location of the vessel’s "official" origin has been defined by the designer or
shipyard. This origin is normally identified with a physical marking, and also shown
on the vessel drawings.
In this example we will establish the origin at the same physical location as the
skipper’s seat on the bridge, however virtually moved down to the waterline. The
seat is located two metres to the starboard side of the vessel’s centre line. All sensors
will then be referenced to this position.
• The depth readout from an echo sounder will be the Depth Below Surface (DBS)
value contained in the NMEA DBS datagram.
• Whenever a sonar is used with short ranges, this will provide a more precise
presentation.
If required, identify the location with a physical marking.
2 Measure the physical location of the transducer.
Note
In this context, the transducer is regarded as a sensor.
a Draw a vertical line from the transducer and up.
Simrad MF90 Installation Manual