N15A-T015 TITLE: Experimental Noise Measurement System for Ship Sonar Design

TECHNOLOGY AREAS: Sensors, Battlespace

ACQUISITION PROGRAM: Torpedo Warning System (PMS 415); HVU Mounted Sonar FNC (ONR)

OBJECTIVE: Develop portable, self-powered affordable sensors that can be attached to the exterior of a ship for measurement and recording of acoustic noise on the hull.

DESCRIPTION: Hull-mounted sonar systems used on ships and submarines are an important capability for underwater sensing. Placement of the hull-mounted sonar is part of a design process that requires knowledge of the noise characteristics of the vessel. Noise can include the effects of (1) hydrodynamic flow as the ship or submarine moves through the water, and (2) acoustic radiation from the ship transmitted through the water or borne by the hull structure. This STTR topic seeks to develop sensors that can be attached to the exterior of a ship and record noise for at least five days. The sensors must be capable of attachment below the water line without permanent hull modification or requiring dry-dock facilities. This topic also seeks to develop analysis software to examine measurements recorded from spatially sparse sensors and, given the hull shape, estimate the noise experienced elsewhere on the hull.

The Navy seeks innovative and cost-effective solutions for this effort with generic applicability to a wide range of ship hulls. Design solutions tailored to a particular ship will be considered less desirable.

PHASE I: Design, develop and test a single sensor that incorporates acoustic pressure and vector sensor capabilities, an integral power source, clock and recording device. The sensor should be watertight and survivable to depths of 100 feet (ft). Develop algorithms and a preliminary design for noise analysis software.

PHASE II: Design and develop a temporary hull-mount mechanism that attaches the sensor under wet conditions and is survivable to speeds of 25 knots. Produce two sensors based on the Phase I results that incorporate this mechanism and test them on a Navy ship or representative vessel. Develop and test prototype software for analysis of multiple sensor recordings that estimates noise elsewhere on the hull.

PHASE III: Produce complete noise measurement system including multiple sensors, software, installation guidance and operating instructions. The company will perform operational demonstrations of the sensor system and software to ensure it meets Navy requirements. The company will also support the Navy in transitioning the technology for Navy use.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Successful development of this system will enable rapid and cost-effective data collections to support hull sonar sensor placement analyses by industry sonar developers. Additional commercial applications might include noise measurements for acoustic fault isolation of machinery on merchant ships.

REFERENCES:
1. Ross, D., "Ship sources of ambient noise," IEEE Journal of Oceanic Engineering, vol.30, no.2, pp.257-261, April 2005.

2. Takaaki Musha, Akira Shinohara, "Evaluation of ship radiated noise level from near-field measurements, "Applied Acoustics, vol.40, no. 1, pp. 69-78, 1993.

3. Shipps, J.C.; Abraham, B.M., "The use of vector sensors for underwater port and waterway security," Sensors for Industry Conference, 2004. Proceedings the ISA/IEEE, pp.41-44, 2004.

4. Johnson, M.P.; Tyack, P.L., "A digital acoustic recording tag for measuring the response of wild marine mammals to sound," IEEE Journal of Oceanic Engineering, vol.28, no.1, pp.3-12, Jan 2003.

KEYWORDS: Accelerometers; acoustic measurement; bio-communications; data recording; hydrophones; sonar

** TOPIC AUTHOR (TPOC) **

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