A system for sonically probing a seabed comprises at least one row of transducers that each can produce a sonic beam, and a corresponding row of sonic detectors. Each transducer is independently energized to produce a narrow sonic beam, with resulting seabed or subsea echoes being detected to produce one pixel of a display formed by an X-Y array of pixels, before a next transducer is energized and its echoes are detected to produce another pixel of the display. When the system detects a large change in echo amplitude at adjacent seabed locations, then scanning at those locations is accentuated by analysis and by additional sonificiation at different frequencies. The transducers are closely spaced, at a center-to-center distance of typically about 3.5 cm, to provide good horizontal resolution. Each transducer is energized to produce a sonic pulse which, dependent on the application, has a carrier frequency of 0.25 MHz. This results in an optimized narrow sonic beam, with each pulse having a duration on the order of 10 to 100 microseconds to produce a modulation frequency on the order of 200 kHz to 5 Khz, and with each pulse having a high maximum energy to create a wide frequency bandwidth in the seabed.
[1]
James J. Solberg,et al.
Analysis of Flow Control in Alternative Manufacturing Configurations
,
1980
.
[2]
Anthony M. Smith,et al.
Reliability-Centered Maintenance
,
1992
.
[3]
Hiromitsu Kumamoto,et al.
Efficient Evaluation of System Reliability by Monte Carlo Method
,
1977,
IEEE Transactions on Reliability.
[4]
Nagen Nagarur.
Some performance measures of flexible manufacturing systems
,
1992
.
[5]
James A. Chismant.
Using discrete simulation modeling to study large-scale system reliability/availability
,
1998,
Comput. Oper. Res..
[6]
Larry H. Crow,et al.
Reliability Analysis for Complex, Repairable Systems
,
1975
.
[7]
Bengt Lennartson,et al.
Performance modeling of automated manufacturing systems
,
1995,
Autom..
[8]
Rajan Suri,et al.
An overview of evaluative models for flexible manufacturing systems
,
1985
.
[9]
Jack R. Meredith,et al.
Effect of maintenance policies on FMS failures
,
1992
.