Compact Low Noise Acoustic Sensors for Sonobuoys
Navy SBIR 2018.2 - Topic N182-136
ONR - Ms. Lore-Anne Ponirakis -
Opens: May 22, 2018 - Closes: June 20, 2018 (8:00 PM ET)


TITLE: Compact Low Noise Acoustic Sensors for Sonobuoys



ACQUISITION PROGRAM: PMA 264 Air Anti-Submarine Warfare Systems Program Office

The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with section 3.5 of the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws.

OBJECTIVE: Develop, fabricate, and demonstrate a compact, low-noise, sensitive underwater acoustic sensor for use in sonobuoy applications.

DESCRIPTION: Existing underwater acoustic sensors found in common sonobuoys include hydrophone and preamplifier circuits in a combined cylindrical package approximately 3.5” in length and 1” in diameter. For purposes of this SBIR topic, the term “sensor” will refer to a combination of a hydrophone and a pre-amplifier. Future sonobuoys will make use of sensor arrays and thus will need to include more sensors packaged into the same fixed volume. The reduction in size can pose a design challenge for sensor developers, since reducing the volume of piezoelectric materials in an acoustic sensor tends to increase susceptibility to thermal noise and compromise performance. In addition to reducing the sensor size, the cost per sensor must be low in order to be suitable for use in an expendable sonobuoy device. The desired specifications for the sensor are:

Maximum Length: 2.25”
Maximum Diameter: .9”
Maximum Noise at 1 kHz: 30 dB at output of the preamplifier
Maximum Noise at 10 kHz: 22 dB at output of the preamplifier
Resonance: >50 kHz
Cost in Production: <$50 for large orders (suggested quantities: 1000+ units)

PHASE I: Identify a sensor design that can be developed to meet the specifications. Undertake two or three notional paper design variations to assess the strength of the approach. Select a design variation to pursue in Phase II, analyze all aspects of the design, and perform a cost analysis for production.

PHASE II: Complete the design selected in Phase I and fabricate a set of 4 prototypes. Complete preliminary performance testing in an acoustic test tank or similar facility. Modify design based on these results and then fabricate an additional 30 sensors and deliver them to the Navy for independent testing.

PHASE III DUAL USE APPLICATIONS: Extensively test a subset of the sensors fabricated in Phase II and test for severe environmental conditions of depth, temperature, and operating time. Modify design based on these results and then fabricate/test an additional 100 sensors. Compare the test results to those of the Phase II sensors to determine consistency of outcomes. Assist the Navy in transitioning the technology to the fleet. Appropriate dual-use applications for the developed technology in the civilian market are for underwater sensing systems—primarily for oceanographic research and hydrographic survey users.


1. Tims, A. C., “Hydrophone Preamplifier Optimization: Prediction of Hydrophone Self-Noise by a Noise Model.” NRL Report 8180, Naval Research Laboratory, 1978.

2. Sherman, Charles H. and Butler, John L. “Transducers and Arrays for Underwater Sound.” Springer, 2007.

3. Rijnja, H. A. J. “Sensitivity of Small Hydrophones.” Acta Acustica united with Acustica, Vol. 30, Number 1, 1974.

4. Beauducel, Claude, and Gautier, Thierry. “Increased sensitivity piezoelectric hydrophones.” Journal of The Acoustical Society of America – 86, 10.1121/1.398589, 1989.

KEYWORDS: Underwater Sensor; Underwater Acoustics; Anti-submarine Warfare; Sonobuoy


Michael Vaccaro




Charles Traweek




These Navy Topics are part of the overall DoD 2018.2 SBIR BAA. The DoD issued its 2018.2 BAA SBIR pre-release on April 20, 2018, which opens to receive proposals on May 22, 2018, and closes June 20, 2018 at 8:00 PM ET.

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