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Watson Forward Looking Sonar
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The Watson Forward Looking Sonar (WFLS) System
(Patent
#5,173,882) was developed to fulfill the market need to collect extremely
high quality sonar imagery and precision depth data from a fixed point
location. A rotating platform tripod assembly with heading and tilt sensor
mechanisms, allow for the acquisition of high quality sonar imagery,
as well as precise depth data using interferometric techniques. The WFLS
sonar imagery and bathymetry data is acquired simultaneously through the
same set transducers. Watson Forward Looking Sonar System
sonar imagery and bathymetry data is stored on an image
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The WFLS System was
designed to collect data in harsh Arctic marine environments. This
requirement led to the development of instrumentation that can withstand
these conditions and can be operated in a straight forward and time efficient
manner, and still meet the criteria for sonar platform stability. For this
reason the material utilized for the basic mechanical structure of the WFLS System is aluminum. The Watson Company Inc. technical approach required the
design of a tripod structure as the main component of the system, so that
the sonar array orientation and stability could be established. The WFLS
tripod platform has a leveling adjustment capability that can be easily
verified.
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Operation of WFLS on Ice
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For WFLS System
orientation a precision heading sensor and an optical level is used for
the exact orientation of the sonar transducers. To index the WFLS System
to a given bearing, the visual level is sighted at a survey
monument. A compass rose with 360 increments for individual degrees in a
circle, is located on the tripod table. The compass rose can be manually
adjusted, and is used to ground
truth the output of the heading sensor.
Rotation speed of the WFLS sonar transducer array is variable in range, from 10 minutes per
revolution, to, 2 minutes per revolution. For practical
operation the range scale of the sonar is variable from 25 meters to 200
meters. The rotation rate is slowed for distant ranges, and
speeded up for close range data acquisition.
Data products generated
from the WFLS include electronic sonar mosaics shown to the right. Ice
gouges are apparent in the mosaic shown to the right.
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