EM124

The EM 124 is designed to perform seabed mapping to full ocean depth with an unsurpassed resolution, coverage, and accuracy. The swath width is typically 6 times the water depth to almost 4000 m depth. A swath width of about 30000 m is generally achievable for deep waters, depending upon bottom conditions and chosen system beamwidth. With a low noise vessel, a swath width of more than 40 km has been achieved.

The EM124 state-of-the-art electronics and separate transmit and receive transducers in a Mills Cross configuration. It utilizes the same field-proven transducers as the EM122, 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, 0.5 x 1 degrees, whereas the smaller 4 x 4 degrees solution allows full ocean depth surveys, even on smaller vessels.

The transmit fan is divided into up to 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 for full ensonification of the seabed with equally distributed footprints, even in bad 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. Two individual transmitting fans are generated with a small difference in tilt giving a constant sounding pattern on the seafloor.

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.