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Full ocean depth high resolution seabed mapping from 10 to 11000 meters

The EM 304 MKII is the successor of the highly acclaimed EM 302 and the EM 304 MKI multibeam echo sounder. Its broad range of functionality supports simultaneous collection of multiple data types, saving time in the planning, execution and analysis phase. The low noise echo sounder delivers superior data which requires minimal post-processing.

With its broad frequency span, this system sets a new standard in the market with no compromises between range and resolution. The EM 304 MKII can map the shallow-to-medium water depths with high resolution and still map the deepest depths with a superior coverage. Compared to the EM 304 MKI, the MKII has an increase of 75% swath performance at 6000m.


The EM 304 MKII uses state-of-the-art electronics and separate transmit and receive transducers in a Mills Cross configuration. It utilizes the same field-proven electronics and transducers from the EM 304 MKI/EM 302, making it easy to upgrade.

The design is highly modular and flexible with compact electronics for easier and faster installation. The flexible transducer design makes it possible to tailor the system to almost any required size.
Ultimate system performance – resolution and range – is achieved with the largest standard size, 0.3 x 0.5 degrees, whereas the smaller 4 x 4 degrees solution can be installed on any vessel of opportunity.

Acoustic ice protection windows can be offered for vessels going to the ice rand and for ice breakers. Both TX and RX ice windows are made of hyperlast, reinforced with titanium rods, proven to withstand surveys across the North Pole.


The transmit fan can be divided into 16 individual sectors in dual swath mode. This allows for unique control of the transmit fan, enabling active stabilization in real time to correct for any yaw and pitch movement of the vessel, while roll stabilization is applied on the receiving beams. The result is a stabilized system—full ensonification of the seabed with an equally distributed footprint in all types of weather conditions, leaving no gaps or holes in the mapped area. All beams are maintained and automatically adjusted according to achievable coverage or operator defined limits. Up to 1600 individual beams are available in dual swath mode. The two individual transmitting fans are generated with a small difference in tilt to provide a constant sounding separation along track, resulting in a dense sounding pattern on the seafloor.


Due to the sector transmission technique, the system produces a strong dampening of multi-bounce interference from false echo, resulting in significantly cleaner data. Near field beam focus is applied in real time, both during transmission and reception. Due to sector transmission, the focal point will be individual for each sector, resulting in a much sharper transmit beam over the entire swath. On reception, the focus is done dynamically for each beam. The result is a much higher resolution representation of the seabed.


The EM 304 MKII is part of the new EM platform designed for future challenges and uses the new KMALL datagram format. The format supports several new features, such as extended backscatter calibration, with more features in continuous development. The new platform is supported by Kognifai, KONGSBERG's open digital ecosystem, bringing opportunities to transform survey operations through digitalization.

Like all KONGSBERG EM multibeam echo sounders, the EM 304 MKII ensures the best operating environment to safeguard marine life inhabiting the survey area through the option to decrease emitted sound levels.


  • Modular design
  • High resolution
  • Wide frequency range
  • FM chirp
  • Roll, pitch, and yaw stabilization
  • Short pulse lengths, large bandwidth
  • Transmit and receive nearfield focusing
  • Water column display and logging
  • Water column phase logging
  • Seabed image
  • Dual swath
  • Extra detections
  • Mammal protection

Realtime Software

Post Processing software

Note: KONGSBERG is not responsible for any system malfunction caused by 3rd party software.

Services et support

  • 24/7 Technical support

    Our 24/7 technical support team is there to help at any time, day or night, wherever your vessel is.

  • Conversions, retrofit and refit

    We understand the importance of having the right parts, available in the right place, at the right time.

  • Training

    Ensure that your crew is properly and thoroughly trained. This will reduce operational risk, downtime and maximise return on asset investment.

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