Broadband Sonar Technology Expected to Set New Market Trend

Two papers published at the International Council for Exploration of the Sea Journal of Marine Science have revealed that broadband-based sonar offers more details than traditional acoustic sonar. The new systems, already tested, have shown that broadband technology has the ability to more accurately detect and identify underwater objects and underwater movement at higher levels of details than traditional single and dual frequency sonar.

The new technology, which is based on over twenty years of research into acoustic imaging modeling technology, analyzes the response of underwater objects to acoustic imaging waves, and compares them to a known database of modeling responses.

Researchers at Woods Hole Oceanographic Institution (WHOI) developed this technology and then implemented it in commercial sonar systems from Edgetech, a company that specializes in mobile underwater sonar scanning systems including broadband acoustic sonar systems. Tim Stanton and Andone Lavery, authors of the papers, have already tested the two systems in operation. The two systems include one that operates between the frequencies of 1.5 kHz to 100 kHz. That system, which is used for the detection of fish, is able to precisely determine the number of fish in a school, the species of fish, the size of the fish, and can pinpoint the areas within the school with the highest and lowest fish densities. The other system operates between the frequencies of 150 and 600 kHz and is used to discern zooplankton from underwater turbulence.

According to the researchers, the flaw with present day sonar is that it only uses one or two acoustic frequencies allowing only one or two points for data analysis. On the other hand, a broadband system uses an infinite continuum of low frequencies, which allows for an infinite number of data points for object identification. Because of the multitude of acoustic frequencies it uses, the broadband sonar is able to establish a detailed fingerprint of the object under observation. In turn, this frequency-fingerprinted response can then be compared and matched with one of thousands of previously frequency-fingerprinted models.

According to the researchers one of the significant results of the tests was that it was able to discern small marine life, such as zooplankton, from water turbulence. This ability to discern and identify accurately at resolutions in the millimeter range is expected to save a significant amount of time for those that depend on accurate underwater identification.

According to Lavery, the technology is available for the commercial market to use. Lavery explained that her “hope is that one of the major companies that makes acoustic systems will pick up on broadband technology and make it accessible to the general user community.” The researchers also indicated that the technology will go forward. The systems are expected to be used on moorings, ships, and underwater vehicles, where they will be used for a wide range of sonar imaging applications.