Reson SeaBat 7125 ROV, Operator'S Manual

Page: 88 / 200

SYSTEM OPERATION
SeaBat 7125 ROV Operator‟s Manual
Page 72 May 30, 2011
Version 3
This value is used in conjunction with the spreading loss coefficient to compute the TVG
(time-varied gain) curve as described in
section 5.7.3.2 below .
For examples on how to use this setting, see
section 6.5.1 Loss of Sound by Absorption .
5.7.3.2 Change the Spreading Loss Coefficient (Spreading)
The Spreading slider allows the operator to enter the amount of cylindrical and spherical
spreading loss that is expected through the ambient water medium. The range available
is from 0 to 60dB, with a recommended initial value of 30. The last selected user setting
is stored and will be recalled upon system startup.
This coefficient value is used in conjunction with the absorption loss value (see
5.7.3.1
above ) to compute the TVG curve applied to the returned signal.
For examples on how to use this setting, see
section 6.5.2 Loss of Sound by Spreading .
5.7.3.3 Set the Sound Velocity
The Sound Velocity slider allows the operator to enter the externally measured speed of
sound through the local water. This value is represented in meters per second, and is
used in Range display and Receiver Beam Steering. The range allowed is from 1400 to
1600m/s.
The Override check box is only available, if an external sound velocity source is
detected.
For examples on how to use this setting, see
section 6.5.3 Sound Velocity .
CAUTION
An online sound velocity probe must be used for providing up-to-date velocities, if the
sonar system is using ED beamforming.
If the system is using EA beamforming, an online sound velocity is not required and an
approximate value from the water column SV data can be entered manually.
5.7.4 Primary Display Settings
The Primary Display Settings tab allows the operator to customize some of the visual
properties of the sonar image.
Figure 24: Sample of Primary Display Settings Tab