Simrad SC90, Installation Manual

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419050/B
Fine tuning the motion reference unit (MRU) offset values
The information from a motion reference unit (MRU) (normally heave, roll and pitch
information) is imported into the SC90 to increase the accuracy of the echo data. For
improved operational accuracy, an external motion reference unit (MRU) may be used.
For optimal SC90 performance, the offset compensation of the motion reference unit
must be as accurate as possible. This task is only applicable is you are using an external
motion reference unit on your SC90.
Prerequisites
The SC90 is turned on, and it is working normally. The
sensor is connected to the SC90.It is switched on and
in normal operation. Neither tools nor instruments are
required.
To do this task, specific environmental requirements
must be met.
• Low wind speed
• Calm sea (Sea state 2 or less)
• Shallow waters
• Flat bottom
Context
A motion reference unit (MRU) measures the vessel’s pitch and roll movements in the
sea. The information provided by the motion sensor is used by the SC90 to stabilize the
echo presentation.
Two methods are used for fine tuning.
• Use the surface reverberation
• Use a flat bottom
Note
This task is only applicable is you are using an external motion reference unit on your
SC90.
Procedure
1 Make sure that the environmental requirements are met.
Simrad SC90 Installation Manual