This type of echo sounder radiates a very wide surface of
the seafloor. With a single impulse it is possible to obtain
a great number of measurements (up to 508) perpendicularly
to the direction of advancement of the boat, with an investigated
corridor usually up to seven/eight times the water depth.
In such way, it is possible to get the total coverage of the
area with a great number of measurements for unity of surface
(for example more than 40 measurements/m2 in waters shallower
than 10 m)
of a multi beam echo sounder
Example of a swath
obtained with a RESON SeaBat 8125 multi beam echo sounder
In order to work properly, the
multi beam echo sounder needs the data calculated by some external
sensors, below described. These data are used in order to obtain
real-time compensation for vessel motion and ray-bending:
is designed to compute vessel attitude (roll, pitch and
heave) mainly caused by the sea waves.
it measures the orientation of the boat accurately
is installed close to the multi beam transducer computing
the sound velocity values continuously
measures the sound velocity profile in the water column.
All the survey activities are
managed using the navigation and acquisition systems equipped
with RESON PDS2000 or QPS QINSy softwares.
These systems provide all the tools to execute the survey, from
the Survey Setup (geodetic parameters, vessel geometry, etc.),
to Survey Planning, to Survey Execution and Quality Control,
to Data Storage.
A huge number of graphical and alpha numeric displays are available,
making the survey activities and the quality control easier.
the Navigation Display is used to display a top view
of the work area with nautical chart in background,
the vessel and the sounding grid, which can be useful
to check the coverage of the survey and the quality
of the data
Moreover, the sounding grid gives immediately a quick
understanding of the morphology and the water depths
in the work area. This is very important working in
very shallow water areas, in order to avoid dangerous
areas and rocky outcrops.
multi beam sounding
ADVANTAGES USING MULTI
BEAM ECHO SOUNDERS
Better accuracy and resolution of the depth measurements
Full coverage of the work area with higher detail
and great density of data. For example it is possible
to obtain more than 40 measurements/m2 in water depths
of about 10 m
Detection and mapping of debris and other underwater
objects (pipeline, wrecks, etc.)
In water depths deeper than 5 or 10 m, the sector
investigated is enough wide to decrease the number
of navigation lines respect to a survey with single
beam echo sounder. It means shorter survey and better
quality/price ratio of the service provided.