multibeamechosounders

Multibeam echosounders (MBES) are sonar systems used to map the seafloor by emitting a wide fan of sound beams from a transducer array. Instead of sending a single vertical ping, MBES generates many beams across a swath, allowing simultaneous depth measurements along a broad strip of the seabed. The depths are calculated from the travel time of each beam, with the angles known from the array geometry and the water’s sound speed profile.

Most MBES units are hull-mounted, but they can also be deployed on towed devices or autonomous platforms. Key components include a multi-element transducer array, a navigation system (GPS and motion sensors), and processing electronics. Modern MBES systems use beamforming to form hundreds of individual beams from the transmitted signal, increasing swath coverage and resolution. Data collection typically requires a sound velocity profile, which corrects range measurements for variations in water properties, and motion data to compensate for vessel roll, pitch, and heave.

Output includes bathymetric depth data and often backscatter intensity, which provides information about seabed composition. Processing produces gridded bathymetric maps, digital elevation models, and terrain attributes for hydrographic charting, dredging, offshore construction, and habitat assessment. MBES data can be integrated with single-beam data for validation and continuity.

Advantages over single-beam systems include higher efficiency, more uniform sounding density, and better seabed characterization. Limitations involve higher cost, greater data volume, and more complex processing and calibration requirements, including accurate sound velocity profiling and motion compensation. MBES has become standard practice in modern hydrographic surveying and marine geoscience.