Reson SeaBat 7125 SV2, Operator'S Manual

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ACTIVE SONAR USAGE
SeaBat 7125 SV2 Operator‟s Manual
Page 100 July 25, 2011
Version 3
6.2.6 Correct Range Setting
Table 2: Incorrect Range Settings
– Examples and Solutions
Figure 33: Range Setting
– Too Long
With the range set too long, the receivers a
re “open” for too long and the system is
recording long after the acoustic returns from the seabed have been received.
Spurious background noise can be amplified, especially when TVG is used, and this
can give noisier data. The ping rate is also reduced thereby reducing sounding density.
This should not be used to artificially reduce the ping rate, rather the range should be
set correctly, and the ping rate should be capped using Max Rate (see
section 5.7.1.4
Set the Maximum Ping Rate (Max Rate) ).
Figure 34: Range Setting
– Too Short
With the range set too short, the outer beams formed are not long enough to reach the
seabed. With no seabed in these beams the bottom detection process can only lock
onto the noise in the water column. An exception to this is if the seafloor to the outer
parts of the swath is of no interest and the user wishes to concentrate on a smaller
seafloor coverage thereby increasing the ping rate and hence sounding density. In this
case the user should reduce the swath coverage of the sonar (see
section 5.7.1.7 Set
Vari-Swath ).