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Interpreting The Sea Scout’s
Forward Display
The Interphase
Sea Scout provides a display which
shows acoustic echo returns from the underwater area
below and ahead of the vessel. The Phased Array
Transducer steers an acoustic beam over a forward arc
whose scan width can be adjusted from approximately 12
to 90 degrees. As the
Sea Scout steers the beam to
different positions, it transmits a pulse of energy and then
waits a defined period of time (depending on the range
selected) to receive any return echoes. As the energy
from this acoustic beam strikes underwater objects or the
bottom, a small portion of the energy is reflected as an
echo back to the transducer. When the echo is received at
the transducer, it is converted into a small electrical signal
and processed for display on the
Sea Scout’s LCD.
Since the
Sea Scout knows the direction in which it sent
the transmit pulse and the time it took to receive the
return echo, it can determine the location of the object or
bottom that created the return echo. As the
Sea Scout
sequentially steps the acoustic beam from the left to right
and in front of the vessel, the LCD display shows a
continuously updated display of the return echoes in their
approximate position in relation to the boat.
It’s important to remember that to show underwater
objects, the
Sea Scout must be able to actually “see”
them. It can not show forward areas that are hidden from
its field of view or are hidden due to obstructions in the
acoustic beam’s path through the water.
Forward View
The
Sea Scout scans from left to right across the boats
bow. The forward scanning elements in the transducer
are positioned so that the plane of the horizontal scan is
angled downward approximately 20 degrees from the
water’s surface (see sketch at right). This downward
angle is designed to help reduce the effects of surface
noise clutter when the water is choppy and to allow
easier mounting of the transducer to the transom of
smaller boats.
As the acoustic sound beam is projected away from the
boat, the cross-sectional diameter of the beam increases.
At a range of approximately 3 to 3.5 times the depth of
the water the sound beam will begin intersecting the
bottom and some of the sound energy that intersects the
bottom will be reflected back and will appear on the
Sea
Scout’s screen as bottom echos.
Plane of Forward Scan is Angled 20 Degrees
Downward From Surface. Forward beam will
reach bottom at approx. 3 to 3.5 times depth
250
500
750
1000
90
180
270
360
Forward Range
Depth
Beam Depth at Various Forward Ranges
Beam Depth =
Approx. .36 X
Forward
Summary of Contents for Sea Scout
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