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Noah Jenkins stands in front of a remotely operated vehicle (ROV) prior to its deployment for an undersea experiment. Photo courtesy of Jenkins.

Why is undersea acoustics important?

An Introduction to Underwater Acoustics by Xavier Lurton, an invaluable reference book for those in the field, provides a nice summary of the practical uses of acoustic waves underwater:

• Detecting and localizing obstacles and targets. This is the main function of sonar (sound navigation and ranging), which is used primarily for military applications such as antisubmarine warfare.
• Measuring characteristics of the marine environment. For example, you can use acoustics to map seafloor topography.
• Transmitting signals. This includes applications such as transmitting data acquired by underwater scientific instruments.

Taking advantage of these practical applications requires designing and building undersea acoustic systems tailored to meet specific needs. For example, the US government collaborates with industry companies to design and build high-performance, long-range sonar systems for naval applications. Undersea acoustics also has a strong presence in academic and research domains, such as universities and navy research labs. Undersea acousticians have successful careers in all of these environments.

Someone with a career in undersea acoustics may be disguised with a title other than “undersea acoustician,” which speaks to how interdisciplinary the field is. The pathway to a career in this area—and the training for working in this space—can vary significantly from person to person. I was initially exposed through an internship at a small company that specialized in developing undersea acoustic systems. The technical staff included people with bachelor’s degrees in engineering, physics, and mathematics. Some also held graduate degrees in those fields.

After completing a bachelor’s degree in applied mathematics, I was hired as an engineer at General Dynamics Applied Physical Sciences. Today, I am a senior engineer in the Undersea Systems and Acoustics Group at Systems & Technology Research (STR). I design, analyze, and implement sonar signal processing algorithms for high-performance systems. These algorithms allow us to extract useful information about an underwater object of interest from signals generated by electromechanical acoustic sensors called hydrophones.

In sonar systems, a typical signal processing chain consists of the following modules: bandpass filtering, beamforming (array processing), detection and clustering, tracking, and finally, classification. Robustly implementing each of these modules requires a strong understanding of the sound propagation physics in the area where the sonar is deployed. To help get this information, we utilize numerical models to simulate how sound propagates in the ocean under assumed environmental parameters. In addition to designing operational algorithms, I sometimes do research to better understand a problem our system needs to address.

There is significant research on undersea acoustics going on, primarily driven by its importance to naval applications. For example, researchers in academia or industry might investigate how a particular ocean phenomenon affects sound propagation or how to exploit the feature of an ocean waveguide to transmit sound very far away.

What I enjoy most about working in undersea acoustics is the breadth of technical fields it intersects with. I work with and learn from people with a variety of technical backgrounds and skill sets. Additionally, many of the projects I work on require at-sea testing and experiments—this has afforded me the opportunity to travel to new coastal and offshore destinations. Working on the unique, challenging problems in this field is both enjoyable and rewarding.