Researchers will develop the first hull attack sensor system to predict underwater radiation noise

South Korean researchers have developed the country’s first hull mounted sensor-based system to predict underwater radiation noise (URN), a key factor in the naval stealth operation. New technologies allow real-time monitoring of the underwater noise levels generated by naval vessels, allowing early detection of abnormal vibrations, improving operational efficiency while reducing maintenance costs.

Under the National Council of Science and Technology, the research team, led by Principal Sunghyun Lee of the Virtual Engineering Research Center of the Korea Institute of Machinery and Materials (KIMM), successfully verified the system through full-scale testing of multiple naval vessels.

Using empirical data collected during ship operations, the team has developed a unique algorithm and sensor placement technology that accurately monitors and predicts both hull vibrations and underwater noise.

Unlike traditional URN analysis methods that require intermittent data collection using external equipment in quiet sea areas where there is no traffic to surrounding vessels, the new system allows for continuous on-board monitoring with real-time updates.

Even with a limited number of sensors, optimized sensor placement and advanced signal processing technology allow the system to maintain high prediction accuracy and achieve errors within 4 dB during actual testing.

This algorithm processes real-time data from accelerometers connected to the vessel’s hull, analyzes vibrational properties, radiation efficiency, and frequency profiles to calculate underwater radiation noise levels. Furthermore, statistical anomaly detection algorithms allow for early identification of abnormal vibration patterns, and adaptable threshold settings can accommodate a variety of operational conditions.

This real-time feature offers a distinct advantage for stealth operations, particularly in detecting changes caused by cavitation or shifting in propulsion modes.

Beyond military applications, the system offers significant benefits for maintenance management and is flexible in integrating into a variety of vessel designs and operations. Streamlined sensor configurations help reduce installation and operational costs while improving overall fleet management.

The researchers further validated the technology by collecting vibration data from sensors mounted on the hull during various operating conditions, including changes in speed. Comprehensive testing was conducted in accordance with International Standards for Underwater Noise Measurement (ISO 17208-1:2016) and actual results consistently show prediction errors within 4 dB.

“This world-class system enables real-time prediction and monitoring of strategically sensitive underwater noise data,” said Kimmmu Principal Sunghyun Lee.

“It not only strengthens the naval stealth capabilities, but also improves early failure detection and maintenance efficiency across diverse naval operations.”

The project was carried out in collaboration with defense contractor Lig Nex1, entitled “Sensor-based surveillance technology installed in a hull for naval propulsion systems.”