A Multibeam Echosounder (MBES) is an acoustic device that uses a very advanced sonar to map the seabed. Acoustic devices emit sound energy in a series of continuous pulses, into the water column and detect the returning echoes. MBES systems emit sound waves, called pings, in a fan shape that enable hydrographers to map the seabed in 3d. The soundwaves interrogate the seafloor along a perpendicular line beneath the ship and return to the receiver. The width of this line is called the swath. To better understand this principle watch this Multibeam Simulation by RealSim.
The achievable swath width of a multibeam system is mostly determined by the depth of the seafloor being surveyed. The maximum depth that can be mapped by a MBES depends on the acoustic frequency it uses. The lower the sound frequency, the further the sound can go. There are different types of MBES systems that use different frequencies to map shallower or deeper water. All INFOMAR vessels are equipped with one or more multibeam systems depending on the depth of water they usually survey in.
All modern MBES deliver three key datasets Bathymetry (or Water depth), Acoustic Backscatter and Water Column Data. INFOMAR routinely collects all three datasets for different applications. For example, Backscatter Data can be used to create habitat maps while Water Column Data is used to map shipwrecks in incredible detail.
In addition, INFOMAR also collects Singlebeam Echosounder (SBES) data. As the name suggests, an SBES system emits one single beam (or pulse) of sound and detects the returning echo. Seafloor bathymetry is recorded as a single continuous track directly underneath the vessel meaning it is less efficient than MBES and consequently not as widely used anymore. Today INFOMAR SBES systems contribute to Water Column Data studies. Further information is available in the corresponding Blue Button on this page.
