EM712

EM712 system configuration can be tailored to the user's requirement, allowing for choice of beam widths as well as transmission modes. Further key advances made for theEM712 include low-noise receiver transducers and electronics in addition to a smaller, lighter form factor, enabling more flexible installation on a wider variety of platforms. Acoustic ice protection windows can be offered for vessels going to the ice edge 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 EM 712 is often paired with other EM systems on larger vessels and can be synchronized with the K-SYNC synchronization unit.

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. The two individual transmitting fans are generated with a small difference in tilt to provide a constantly sounding separation along track, resulting in a dense 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 lime, 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.

Image credit: Norwegian Mapping Authority Hydrographic Services

The EM 712 ice protected transducer modules have a thin titanium sheet moulded into the transducer face. This sheet distributes the load of anything impacting the transducer and provides some scratch protection when moving through areas with ice. The system includes an ice reinforced casket, titanium sheet moulded into the transducer face, and an ice reinforced mounting frame and cover plate. This is not the same as an “ice window” and is not intended for use to actively break ice. The anticipated reduced performance is on the order of 3dB or less.