Reson SeaBat 7125 ROV, Operator'S Manual

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ACTIVE SONAR USAGE
SeaBat 7125 ROV Operator‟s Manual
Page 89 May 30, 2011
Version 3
Figure 33: Range Setting
– The Exception
If you are operating in relatively deep water to the limits of operation and the outer
parts of the swath exceed the acoustic range of the sonar, the user should reduce the
swath coverage (see
section 5.7.1.6 Set Variable Swath ) to cover the seabed that is
visible only. This will increase the ping rate and reduce noise picked up for these
visible beams.
6.2.7 Use of Gates
The depth gates, with no input from a motion sensor, will orient themselves parallel to
the horizontal plane of the sonar head, as shown by the Min and MaxDepth lines in
Figure 34 . In this series of illustrations, the bottom detect dots are shown as a horizontal
line (Line A or B) with dashed lines representing depth gates above and below the
bottom and no vessel r
oll present. Visualize the bottom as being in the „layer‟ formed by
the depth gates.
Sonar Head
MinDepth
MaxDepth
Line A
Figure 34: Depth Gates, With No Roll
Figure 35 shows the same bottom image with a small roll value to port. Notice that the
ends of the swath have been cut off due to the action of the static depth gates (no
motion sensor applied). In this figure, and all remaining figures in this discussion, the
bottom is flat.