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CERES is a company specializing in
underwater technologies – research, mapping, surveys and expertise.
We use
specialized equipment, and all our personnel are qualified for every mission
underwater – oceanography, positioning, mapping, professional diving etc.
The state-of-the-art equipment
we use can be rapidly deployed anywhere in the world.
Our proprietary
acoustic imaging systems, via two side scan sonar EGG 272 TD (EDGETECH), and
the real-time data analysis of TRITON IMAGING INC (Isis Sonar, Survey Office,
Delph Map, Delph nav) provide a direct mosaic image integrated with a
geographical information system.
All the hardware
and software belongs to CERES.
Although tasks are shared
between various team members, the final analysis is examined by the whole team,
ensuring in this way a high level of quality control.
SIDE-SCAN SONAR
 
CERES digital
acoustic system for survey / TRITON IMAGING
INC. sonar/TRITON IMAGING INC. computer / Isis
Sonar/Target pro/Delphmap
Side-scan sonar
Edge Tech 272TD 100/400 Khz / 150 meters Kevlar cable / Qualified CERES
technician
This sonar
provides an image resolution of 10cm, and a positioning accuracy of 1 meter under normal conditions.
SIDE-SCAN
SONAR DATA ACQUISITION
A picture of the
geomorphology of the seabed is taken using the acoustic imagery of the
side-scan sonar. This technique allows us to understand the sedimentary
phenomena of the seabed, and to map the zones accurately.
Very accurate
positioning is required in order to provide a good mosaic of each waveband.
The sonar system
includes: a cylindrical tow fish with stern stabilizers, a transceiver
A computer for
recording real-time data, a 150 meter Kevlar cable for guiding the tow fish,
and for data transmission
The 220 volt
power supply is provided either from the vessel or from a generator.
These systems
make it possible to save the real-time digital images, and to develop the
mosaic of wavebands. We maintain the accuracy of our findings by the ceaseless
supervision of each profile. Since each image is position-referenced, it is
possible to know the exact position of each object, as also the surrounding
sand and/or rocks on the seabed.
Side-scan sonar
surveys provide a continuous map of the seabed. The acoustic image delineates
accurately the various structures on the seabed.
The principal is
based on variations in the coefficient of reflection. The acoustic signal is
sent by the two transducers on the tow fish. The signal varies in intensity
depending on the changing characteristic of the seabed.
The range of
each transducer can be fixed between 25 and 200 meters, allowing for radial bands between 50 and 400 meters. The CERES sonar we use is the side-scan EDGETECH 272TD, 100/400 Khz.
System
initialization is done through a PC, using Isis Sonar data acquisition
technology. It is possible to modify the contrast of each image. This level of
control is essential when analyzing real-time data with Isis and Delph Map
software.
In shallow
waters, the tow fish is not towed but is attached to the bottom of the vessel.
The data acquisition software – TRITON IMAGING INC.’s Isis Sonar – analyzes the
position references provided by the D-GPS, producing a mosaic map along with
the survey data.
In this way,
significant time savings are made. Where necessary, the technician can adjust
the survey parameters for each zone.
The combination
of sonar wavebands makes it possible to develop a mosaic map of all the
surveyed zones, using the OFFICE SURVEY software from TRITON ELICS.
 
The data can be
used to determine the nature of sediments on the seabed, as also the
positioning of any rocks, using Delph Map software.
Delph Map works
like a classic GIS, providing outlines of sediments, rocky zones, plus any
objects such as wrecks, underwater cables, as also any signs of dredging or
scouring of the seabed by trawlers. This acoustic data can then be exported to
other GIS software if necessary.
The Delph Map
acoustic mosaic can be transferred to a GIS such as MAPINFO or ARCVIEW, making
it possible to profile the contours of the sand or mud on the seabed, plus any
rocky areas:
To position
accurately all rocks and other objects
To profile zones
of seaweed
To characterize
the morphology of the seabed
To define
suspect objects such as wrecks and underwater cables
REPRODUCTION
OF THE SIG AND MAPS
The final report
includes detailed maps with all appropriate geographic reference data, plus
many photos and illustrations.
The report is
available both on a CD-ROM and also in hard copy, at different scales.
 
 
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