Multibeam sonar is a kind of active sonar system that scans the seafloor and detects objects in the water column or on the waters surface. Together, the sonar’s numerous physical sensors form a transducer array, which broadcasts and receives sound pulses that map the seafloor or identify other objects. A multibeam array is typically mounted directly to the ship’s hull.
How does it work?
In contrast to single beam sonar, which uses a single sensor to map the bottom, multibeam sonar for marine use simultaneously creates a fan-shaped pattern of sonar beams (or sound waves). This area encompasses both the area directly beneath the ship and the space on either side. Multibeam collects data on two dimensions: depth to the bottom and backscatter. Bathymetry, or the seabed depth, is calculated by the time required for the sound to leave the array, strike the bottom, and return to the array.
Onboard the ship, scientists measure the speed of sound in the sea they are surveying to convert the ship’s two-way transit time to the bottom to a depth measurement. The term “backscatter” refers to the strength of the sound echo that returns to the multibeam array.
Backscatter data can be used to deduce the geological makeup of the seafloor or individual objects on it. For example, more rigid, stonier materials, such as dirt tend to reflect more sound.
Additionally, multibeam sonars can collect data on the backscatter of sound-reflecting objects in the water column. Backscatter data from the water column can be used to visualize objects floating in it, such as three-dimensional formations associated with shipwrecks, bubble plumes erupting from the bottom, and thick biological layers.
What happens next?
Onboard computers collect this data, which is then analyzed by hydrographers to create vibrant two or three dimensional bathymetric maps that aid in seeing the bottom. The bathymetric map below uses warmer hues (red and orange) to represent shallower areas, while cooler colors (yellow and green) show deeper regions.
The Critical Role Of Multi-Beam Sonar
Often, the first step in studying a new region is to perform a multibeam sonar scan after determining the depth, shape, and character of the seabed. The sediment character obtained by multibeam offers information on the species there, assisting in the habitat suitability mapping process. The initial multibeam mapping lays the framework for further in-depth investigation and analysis of our ocean.
A Multibeam Sonar is suitable for a wide variety of applications.
- Dredging or construction beneath the surface of the sea
- Constructing a bathymetric map
- The turbidity of the water column is being mapped.
- Hydrographic mapping of aquatic environments
Exploration of cultural treasures beneath the sea
Conducting hydrographic surveys in mining
Multibeam echo sounders profit from the ability to totally cover the seafloor by scanning it with a fan of narrow acoustic beams. The detailed seafloor maps obtained as a result are superior to those generated by single-beam mapping. The maps are developed more quickly, which minimizes the amount of time needed for surveys.
Multibeam sonar is the most effective approach for undersea mapping since it generates the most stunning findings.