Prerequisites
For accurate location of the motion reference unit (MRU), you need the detailed vessel drawings. The information about the installation angles must be retrieved from the reports provided by the personnel that installed
the equipment. For maximum accuracy, we strongly recommend that you use the information provided by a dimensional survey.
Neither tools nor instruments are required. The CS90 is turned on, and it is working normally.
Context
The motion reference unit (MRU) measures the roll and pitch motions of the vessel. Some sensor models also measure heave.
On the MRU page, you must define the physical location of the motion reference unit related to the reference point you created on the
Ship page. The rotation around the X, Y and Z axis is used to compensate for misalignments made during the physical installation of the
motion reference unit. Such misalignments occur if the sensor is not placed in parallel with the vessel’s horizontal and/or
vertical planes. The required accuracy of the offset and rotation angles depends on the accuracy requirement for the CS90 data.
Procedure
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On the Setup menu, select Installation.
Observe that the Installation dialog box opens. This dialog box contains a number of pages selected from the menu on the left side.
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On the left side of the Installation dialog box, select the small white triangle next to Installation Parameters.
Observe that a menu opens with access to all the individual pages.
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Select MRU to open the page.
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a |
From the vessel drawings, extract the relevant offset information, and insert those values. |
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From the information provided by the personnel installing the motion sensor, obtain the relevant rotation information. |
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Make sure that the correct offset values have been inserted. |
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Make sure that the correct installation angles have been inserted. |
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Record the information in the result table. |
NoteThe Kongsberg Seapath® - and other GPS systems - allow you to define the MRU location in the positioning system. If this is done, the MRU offset values in the CS90 must be set to 0 (zero) to avoid "dual compensation". The rotation information is normally not recorded by the positioning system, and must therefore be defined in the CS90.
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Select Cancel to close the dialog box without making any changes. |