Teledyne SeaBat T Series, Operator'S Manual, Page: 51 / 152

ACTIVE SONAR USAGE
SeaBat T-Series Subsea Operator's Manual Page 39 January 31, 2019
Version 7
6.2.9.2 FlexMode 8

Designed for pipeline or umbilical profiling. Provides equidistant beam spacing for the
full swath coverage together with a high-density equiangular sector which may be
steered toward the detail area of interest.

In this mode the system is started with a 140° wedge and an alternative beam
distribution is used which concentrates the majority of beams into a central sector.
30%
Total swath
High density
sector
Low density
sector
Low density
sector
Default settings
Total swath: 90
°
High density sector: 45 ° centered
Altitude: 5m
DTM density: 0.1m
Figure 9: Graphic Illustration of FlexMode
FlexMode provides a combination of a high density of beams on and around the object location
and a reduced density of soundings for the rest of the swath. The low-density spacing is defined
by the operator (with the slider for Constant seafloor spacing) and the high-density spacing is
computed by optimization based on survey parameters.
For instructions on how to adjust this setting, refer to the RESON Sonar UI User Manual ( see
Appendix E Reference Documentation ).
6.2.10 Use of Gates
Applying range and/or depth gates to the bottom detection process aids in noise reduction and
correcting for a tilted sonar head.

No Gates: The bottom detection process searches the entirety of each beam for the bottom.

Absolute Gates:
o
Depth: Forces bottom detection to occur within the Min/Max Depth limits set. If
the seabed falls outside the limits, bathymetry data will fail and cannot be
recovered.
o
Range: Forces bottom detection to occur within the Min/Max Range limits set. If
the seabed falls outside the limits, bathymetry data will fail and cannot be
recovered.
8 FlexMode is an optional add-on feature (see Table 1 ).