Teledyne SeaBat T Series, Operator'S Manual, Page: 75 / 152

SYSTEM PERFORMANCE AND DATA TYPES
SeaBat T-Series Subsea Operator's Manual Page 63 January 31, 2019
Version 7
The standard dual head implementation uses time multiplexing to achieve synchronized
operation. The result is reduced ping rate per head and asymmetric sea floor swaths. FRDH uses
X-Range (see
7.4 above ) to achieve dual head operation which has the double effect of range
and ping rate increase. In FRDH the systems are synchronized and ping simultaneously at a high
rate. (See also
section 6.3.4.2 Pipe Inspection with Dual Head Systems .)
Standard dual head with alternate pings FRDH with simultaneous pings
Figure 37: Dual Head Synchronization of Pings
7.7 Quality
The quality of each bathymetric bottom detection point is evaluated by the sonar. For instructions
on how to customize some of the visual properties of the sonar image, refer to the RESON Sonar
UI User Manual (
see Appendix E Reference Documentation ).
7.7.1 Brightness Test
The brightness test measures the signal-to-noise ratio (SNR) of the signal strength (magnitude)
near the bottom detection point (as determined by the bottom detection algorithm) versus the
background noise in the rest of the beam.
The signal strength is the mean of the square of the sample intensity around the bottom detection
point. The number of samples used is marked ‘A’ in
Figure 38 and is a small percentage of the
total number of samples. The noise is based on a mean of the square of the samples in the
second half of the “tail” of the detection window (marked ‘B’ in
Figure 38 ) and the square of the
samples in the “head” of the water column (before the first return – marked ‘C’ in Figure 38 ).
Beams, whose SNR is greater than a predetermined threshold, will be flagged as passing the
brightness test.
For instructions on how to display the test results, refer to the RESON Sonar UI User Manual
(
see Appendix E Reference Documentation ).