For deep water mapping
EM 122 multibeam echosounder is a high performance echosounder for deep water
mapping with up to 288 simultaneous beams.
The EM 122 is designed to perform seabed mapping to full ocean depth with an
unsurpassed resolution, coverage and accuracy. The system is cost effective, reliable,
and easily operated. The design of the EM 122 is based on more than 50 years of
hydrographic experience with echo sounders, sonars and underwater positioning for
civilian and military use. It is the latest model in a series of deep sea multibeam
echo sounders started with the EM 12 in 1990 and followed by the EM 121 and the
EM 120, of which about 40 systems are operational.
Up to four times better resolution
It uses the same transducers as in the EM 120 but with new electronics and software.
Compared with the EM 120 the EM 122 has up to four times the resolution in terms
of sounding density through inclusion of multiping capability and more than twice
the number of detections per swath. High density signal processing is a major improvement,
to keep the acoustic footprint size small even for the outer beams in the swath.
In typical ocean depths a sounding spacing of about 50 m across and along is achievable.
25 percent more swath width
The achievable swath width of the EM 122 is in the order of 30,000 m, or about
25% more than possible with the EM 120. This is obtained by using long FM chirps
which gains about 15 dB in signal to noise ratio compared to CW pulses. The EM 122
is a complete system. All necessary sensor interfaces, data displays for quality
control and sensor calibration, seabed visualization, and data logging are a standard
part of the system, as is integrated seabed acoustical imaging capability (side scan).
Meeting the strictest IHO requirements
Including a higher frequency multibeam echo sounder such as EM 710 with the EM
122 system can give a total system solution meeting the strictest IHO requirements
for all water depths. As proven with the EM 120, an accuracy of better than 0.2%
of depth in deep waters is readily achievable with the EM 122.