POS MV V5 Installation and Operation Guide
Installation
2-8
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Ideally, install the IMU at a location for which you require roll, pitch, heading and heave
measurements. Usually this implies mounting the IMU close to, or even on, the multibeam
transducer. The chosen location must provide rigid support so that the IMU does not move
relative to the GNSS antennas; see GNSS System on page 2-5.
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It is not necessary to install the IMU at the vessel’s centre of rotation. There is no degradati
on of
POS MV performance if the IMU is mounted away from the vessel’s centre of rotation, although
this offset should be measured and applied during configuration of the system; see the POS MV
Configuration topic starting on page 4-7.
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There is a label on the top plate of the IMU to identify its sensing axis. It is not required to align
these marks closely with the vessel or the multibeam transducer. Instead, measure the mounting
angles, save them in the PCS when you first power-on and configure the system.
•
Two offset holes are predrilled in the base to accept 5 mm (0.197 in) diameter alignment pins.
These holes maintain IMU orientation and alignment when the unit is replaced, see Figure 5. Two
colinear slots are machined in the base to mate with corresponding rails on the IMU mounting
plate. These slots maintain IMU alignment on the mounting plate when the unit is replaced but
allow the orientation to be reversed in case of cable interference during installation.
Figure 5: Typical IMU Mounting Features
Install the IMU
Once a suitable mounting location is selected, perform the following steps to install the IMU:
1. Apply a thin film of anti-seize grease from the supplied packet all around the alignment pins or
rails, whichever is used, to prevent the IMU housing from becoming stuck on the mounting plate.