Simrad ME70 User Manual

Simrad ME70

M A X I M I Z I N G Y O U R P E R F O R M A N C E A T S E A

www.SIMRAD.com

Scientic multibeam echo sounder system

We are proud to introduce the world’s rst quantitative
multibeam echo sounder for shery research applications

System description

(CD10104G)

System overview

The Simrad ME70 offers

quantitative data and high operational

exibility. It provides a congurable
wide fan of stabilized and calibrated
beams for biomass estimation, sh
school characterization. and behaviour
studies.

All beams can be congured as
split beams providing data for single
target analysis, such as target strength
measurements and target tracking.

The sector of calibrated narrow
split beams with low sidelobe levels

and short pulse lengths allow for

accurate biomass estimation very
close to the bottom. The ability to
adjust the athwartship centre angle of
the fan enables you to use the system
for studying sh close to ridges and
slopes. The design also permits you
to use all the beams over the full
frequency range pointing in one
direction for frequency comparison.

Not just an ordinary

multibeam sounder

Within the bandwidth of the
transducer, the limits for beam
steering, and the minimum achievable
beam opening, you can select the
directions, frequencies, and opening
angles for the beams in the Simrad
ME70.

You will be able to congure the
system to t your requirements, and
the system will provide you with a
real-time display for quality control of
the current data acquisition.

The system conguration can be
tailored to any user requirements,
allowing for choice of beamwidths as
well as transmission modes.

Low sidelobe levels and

beam interleakage

Low sidelobes are important for
two reasons. The obvious one is to
avoid that strong targets in side lobes
are mistaken for weak targets in the
main lobe. Secondly, you do not wish
to see strong bottom echoes from the
sidelobes. Even the vertical receiver
beam may benet from low sidelobes

Key points

• The Simrad ME70 operates in

the 70 to 120 kHz frequency
range.

• The Simrad ME70 provides

a congurable acoustic fan
containing 3 to 45 stabilized
beams.

• All beams can be congured as
split beams.

• Calibration software included.

• Minimum beam opening is

2° depending on operational

frequency and steering.

• 140° maximum total swath
width.

• The athwartship centre angle
of the fan can be adjusted from
+45° to -45°.

• Minimum acquisition depth
is less than 1 m below the
transducer depending on beam
mode conguration.

• Sidelobe levels and beam
interleakage are adjustable
from -35 to -70 dB depending
on beamwidth and frequency
conguration.

in case of a sloping bottom.

Very low two-way sidelobe levels
are obtained by using two-way side
lobe suppression. Very low beam
interleakage is obtained by using

Frequency Rotated Directional
Transmission (FRDT) where the

frequency band is distributed over all
the beams.

Since each beam has its own
frequency and the fan width is
congurable, the design also allows
you to use all the beams over the
full frequency range pointing in one
direction for frequency analysis of
targets.

Calibration

A calibration utility is
implemented as a special built-in
function in the Simrad ME70 system.
Each beam conguration of interest
can be calibrated using a reference
target located under the ship.

Individual gain parameters for
each beam are adjusted to provide
calibrated target strength and volume
backscattering strength measurements.

Splitbeam conguration

All beams can be congured
as split beams. In addition, two
adjustable reference split beams are
available. These allow you to compare

ME70 data with data from other split

beam systems, for example the EK60.
The reference beams can for example
have 7x7 degrees opening angles, and
operate on 70 and 120 kHz.

The data from the individual split

beams are presented in the same way
as on other Simrad scientic sounders.

Data output

It is possible to set up continuous
output of all beam data. This can be
used for echo integration and 3D
visualisation. The output data for each
beam include for example:

• non-TVG compensated sample

power and sample angle

• 20 log R compensated sample Sv

• 40 log R compensated sample TS

• 40 log R compensated single target

detections

• Detected depth

It is also possible to output the
element data for post processing and
analysis purposes.

Remote operation

Remote systems, such as data
loggers and external post-processing
systems, can subscribe to data and
parameters from the Simrad ME70.
The parameters can also be queried
and dened by the remote system. In
this way the communication between
the ME70 and the remote system can
become an efcient, congurable,
two-way communication.

Screen capture example and system diagram

Operator

station

Power

cabinets

(CD10102C)

TRXU

Transceivers

Beamforming

computers

Network

controller

(CD93003A)

MENU

PWR

This capture provides a typical presentation of sh schools. You can see ve of the 31 beams, as well as the fan

presentation. The menu is hidden from view. (Data kindly provided by Ifremer, France.)

System diagram

Operator station

The operator station comprises a computer running

Windows XP® operating system. It is connected to the ship’s

network, and can communicate with external post-processing
applications.

Transceiver

The transceiver circuitry comprises three transceiver
shelves, a network controller, and six beamforming
computers.

Power Cabinets

Three separate power cabinets provide the operation power
to the TRXU Transceivers.

Transducer

The transducer array is mounted in a circular housing. Its
outer diameter is 677 mm. The array contains 800 individual
elements.

Technical specication

Strandpromenaden 50
P.O.Box 111
N-3191 Horten,
Norway

Sim rad Hort en AS

Telephone: [phone]
Telefax: [phone]

[e-mail]

www .simr ad.com

System

• Scientic multibeam echo sounder

Acoustics

Frequency range

• 70 kHz to 120 kHz

Beams

• Organisation: Fan

• Total number of beams:
Maximum 45 beams in fan
plus two reference beams

• Number of split beams:
Maximum 45 split beams in fan
plus two reference beams

Beam opening angles

• Alongship: Selectable 2° to 20°

• Athwartship: Selectable 2° to 20°

• Opening angles depend on beam

steering and frequency.

Operating sectors

• Athwartship: 60°
Maximum 140º with reduced
sidelobe suppression

• Athwartship sector centre
angle: ±45º

• Alongship sector centre
angle: ±5º

Motion compensation

• Roll: ±10°

• Pitch: ±5°

• Heave

Sidelobe and beam
interleakage

• Alongship: Less than -35 dB

• Athwartship: Less than -35 dB

• Congurable depending on

beamwidth and frequency
conguration.

Transmission

• FM with pulse duration
128 to 5120 µs

• CW with pulse duration

64 to 5120 µs

• Source level: > 225 dB (depending
on beam opening and frequency)

Receiving

• Receiver dynamic range: 150 dB

(instantaneous)

Calibration

• Calibration software included

• Target: Tungsten sphere

Hardware

Transducer

• Number of elements: 800

• Technology: Ceramic polymer

composite

• Housing: Circular

• Housing diameter: 700 mm

Transceiver Unit

• Individual Tx channels: 800

• Individual Rx channels: 800

• Beamforming: Cluster of six

computers

• Communication: 1 Gb Ethernet

• Physical dimensions:

Height: 1921 mm
Depth: 900 mm
Width: 600 mm

Power cabinets

• Quantity: Three cabinets

• Physical dimensions:
Height: 812 mm
Depth: 418 mm
Width: 600 mm

Operator Station

• Type: Commercial workstation

• Operating system: Microsoft®

Windows XP®

Optional systems

• Element data logger

• Bathymetric processing system

The transducer array set up for test

and calibration at Simrad’s laboratory

Note that technical specications can
be altered without prior notication!

(855-165184 / Rev.C / November 2006)