Transducer Measurements; Transducer Heading; Transducer Roll And Pitch - Kongsberg EM 710 Installation Manual

8.4 Transducer Measurements

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The measurement should be taken on both sides of the vessel and
averaged to remove any roll effects. Simultaneous measurements
are required if the vessel is moving.
It may be most practical to perform these measurements on the
transducer mounting frames before installation of the transducer
modules. A final verification after module installation is then
required.
Note that it is also necessary to ensure that the final transducer
array face is flat with a maximum deviation from flatness of ±0.2
mm peak to peak including any rotation.

8.4.1 Transducer heading

The heading of the transducers is measured as the average
heading of the two fore-and-aft oriented sides of each transducer
arrays. Thus, the heading of the transmit transducer is the
heading along the keel, while the heading of the receiver array is
the heading across the keel. For the receive transducer it may be
better to measure the heading along the keel, and then subtract
90º to achieve the correct value. The measurement accuracy is
required to be within one fifth of the beamwidth of the transmit
transducer.
Note however that the measurement accuracy of the relative
heading between the transmit and receive transducers must be
better than 0.05º.

8.4.2 Transducer roll and pitch

Roll and pitch measurements are made according to standard
conventions with positive pitch angle if the transmitter array's
forward end is above the aft end (tilts up), and positive roll if the
starboard side of the receiver array is lower than the port side.
Note that the roll and pitch angles to be measured are relative
to the horizontal plane as defined by the vessel's coordinate
system. I.e. for roll the angle that the transducer's y-axis have
with respect to the horizontal and for pitch the angle that the
transducers x-axis have with respect to the horizontal plane. The
multibeam echo sounder converts the measured angles as entered
into the installation menu to rotation angles before use i.e. do not
do such a conversion before entering them into the system.
The required measurement accuracy is given in the table below.
alignment
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