The word SONAR refers to a device that utilizes sound to identify objects inside a water column (sound navigation and ranging). Active sonars produce their own unique sound waves and analyze reflected (echo) waves (echosounder). Active sonars are available in multibeam and single beam configurations. Underwater, multibeam sonar may be used to see the soil topography.
How Does A Multibeam Sonar Function?
Multibeam sonar for marine survey operates on the following principle: a projector creates sound waves picked up by a receiver or hydrophone. A transmitter is referred to as a transducer if it can both produce and receive sound waves. The travel duration or energy of the reflected waves can determine the depth or bottom type. The outcomes are dependent on the frequencies transmitted. Because low frequencies are less absorbed, they can travel further than high frequencies. This is why low frequencies monitor a large region with a lesser resolution than high frequencies.
Multibeam sonar is capable of emitting several single narrow beams. The transducer is placed in the keel of the vessel and generates a variety of sound waves. Thus, the seabed is scanned using a line of continuous points perpendicular to the vessel’s journey direction. The swath length is the width of every line drawn on the soil. It can be represented in meters or as the angle (in degrees) at which the line is produced. The transducer determines the timing and energy differential between emitted and reflected sound waves. As a result, the depth and characteristics of the seabed may be calculated. An even hard surface reflects more waves than an uneven substrate.
Apart from the seabed, a vessel mounted with a multibeam sonar can also map the features of the water column. The emitted beams interact with the particles in the water column and create reflections of their own. One may intuitively deduce that the quantity of reflected energy is proportional to the number of particles in the water column. In practice, the particle size and type, as well as the transmitted frequency, are critical. Nowadays, much study is being conducted on the connection between multibeam data from water columns and turbidity. To know the perfect multibeam sonar that will suit your needs, do visit R2Sonic to check on the different varieties that they offer.
Single Beam Vs Multibeam Sonar
Do you want to see a single vs. multibeam sonars comaprison? A single beam system, which generally has beam widths ranging from 10 to 30 degrees, estimates depth by measuring the distance between the main beam and the seabed along with the shortest slant range. Slant range and elevation angle estimations are provided by multibeam (swath sonar) systems along a set azimuth in a sequence of measurements. This approach is preferred since it measures the entire area of the seabed rather than just a single line of it.
A Multibeam Sonar Can be Used In
- Underwater construction or dredging.
- Bathymetric map making
- Water column turbidity mapping
- Underwater habitat mapping
- Underwater marine cultural heritage mapping
The Conclusion
The advantages of multibeam echo sounders are that they scan the seabed using a fan of thin acoustic beams, allowing them to cover the whole bottom with complete coverage. Compared to single-beam mapping, the resultant seabed maps are more detailed than those obtained through single-beam mapping. The maps are generated more quickly, which reduces the amount of time required for ship surveying.
For the best results in underwater mapping, a multibeam sonar is the best choice you can make.
