Multibeam sonar is an active sonar system that scans the bottom and identifies objects in the water column or on the surface. The sonar’s many physical sensors form a transducer array, which broadcasts and receives sound pulses to map the seafloor or detect other objects. A multibeam array is often connected directly to the ship’s hull.
How does it operate?
In contrast to single beam sonar, which uses a single transducer to map the bottom, multibeam sonar produces many sonar beams (or sound waves) in a fan-shaped pattern simultaneously. This covers both the region directly beneath the ship and the space on each side. Multibeam collects two kinds of information: depth to the bottom and backscatter. The time it requires for the sound wave to leave the array, strike the bottom, and return to the variety determines bathymetry or seabed depth.
Scientists aboard the ship measure the speed of sound in the water they are surveying to translate the two-way transit time between the boat and the bottom to a depth measurement. Backscatter is a metric of the intensity of the sound echo that returns to the multibeam array.
Backscatter data may be used to determine the geological makeup of the seafloor or individual objects on it. Harder, rocky materials, for example, tend to reflect more sound than softer materials like dirt.
Multibeam sonars may also collect backscatter data from objects in the water column that reflect sound. Backscatter data from the water column may be used to display suspended objects in the water column, such as three-dimensional structures associated with shipwrecks, bubble plumes erupting from the bottom, and dense biological layers.
What comes next?
This data is collected onboard by computers, which is then analyzed by hydrographers to create colorful two- or three-dimensional bathymetric (water depth) maps that help visualize the bottom. The warmer colors (red and orange) indicate shallower areas in the bathymetric map below, while the cooler colors (yellow and green) indicate deeper areas.
The Importance of Multi-Beam Sonar
After determining the seabed’s depth, shape, and character, the first step in researching a new location is often to conduct a multibeam sonar survey. The sediment character identified by multibeam gives information on the species that may live nearby, aiding in mapping habitat suitability. The initial multibeam mapping lays the basis for more in-depth research and investigation of our ocean.
A Multibeam Sonar may be used in a wide range of applications.
- Dredging or building under the water’s surface and inland surveys
- Creating a bathymetric map
- The turbidity of the water column is being mapped.
- Hydrographic mapping of the aquatic environment
- Exploration of cultural riches beneath the sea
Multibeam echo sounders benefit from scanning the seabed with a fan of narrow acoustic beams, allowing them to cover the bottom thoroughly. The detailed seabed maps produced are better than those produced by single-beam mapping. The maps are generated more quickly, which decreases the time required for surveys.
Multibeam sonar is the most efficient method for sea bed mapping since it delivers the most remarkable findings.