Reson SeaBat 7125 ROV, Operator'S Manual

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ACTIVE SONAR USAGE
SeaBat 7125 ROV Operator‟s Manual
Page 92 May 30, 2011
Version 3
6.3.1.1 Auto Pilot Sensitivity
In general, the greater the sensitivity setting is, the greater the range. While this lowers
the risk of losing part of the swath due to range, it also lowers the maximum ping rate.
Lower sensitivity settings would be appropriate for roll-stabilized systems or
very calm conditions without roll stabilization.
Higher sensitivity settings (>20%) would be safer for non-roll-stabilized
systems and/or highly featured bottoms.
6.3.1.2 Auto Pilot Limitations
The Auto Pilot functionality is difficult to optimize for all imaginable conditions and it
should be expected that occasionally, the functionality will fail when subjected to
marginal conditions. Occurrences such as rapidly changing seafloor topography, poor
signal-to-noise ratio (possibly when operating at extreme ranges) and environmental
conditions such as flow noise, bubbles around the array, and bio activity could all cause
intermittent failure of Auto Pilot. See also
section 6.6 below.
6.3.2 Roll Stabilization
Roll stabilization is an important feature related directly to system efficiency which allows
the swath width on the seafloor to be maximized, thus increasing line spacing and
reducing vessel time.
Under zero roll conditions, the swath is vertical and the center of the swath is directly
below the vessel.
Figure 37: Swath under Zero Roll Conditions
When the vessel rolls the swath is rotated and the projected swath on the seafloor is
laterally displaced.