MBES

Multibeam sonar（MBES） is a type of active sonar system used to map the seafloor and detect objects in the water column or along the seafloor. The multiple physical sensors of the sonar – called a transducer array – send and receive sound pulses that map the seafloor or detect other objects. A multibeam arrayis usually mounted directly on the ship’s hull.

How It Works

Unlike single-beam sonar, which uses just one transducer to map the seafloor, a multibeam sonar sends out multiple, simultaneous sonar beams (or sound waves) at once in a fan-shaped pattern. This covers the space both directly under the ship and out to each side. Multibeam collects two types of data: seafloor depth and backscatter. The seafloor depth, or bathymetry, is computed by measuring the time it takes for the sound to leave the array, hit the seafloor, and return to the array. Scientists onboard the ship take measurements of the speed of sound in the water where they are surveying so they can translate the two-way travel time from the ship to the seafloor and back as a depth measurement. Backscatter is a measurement of the intensity of the sound echo that reflects back to the multibeam array.