Acoustically Transparent Mid-Frequency SONAR Projector
Navy SBIR 2020.1 - Topic N201-066
NAVSEA - Mr. Dean Putnam -
Opens: January 14, 2020 - Closes: February 26, 2020 (8:00 PM ET)


TITLE: Acoustically Transparent Mid-Frequency SONAR Projector


TECHNOLOGY AREA(S): Battlespace, Electronics, Sensors

ACQUISITION PROGRAM: PEO IWS-5A: Integrated Warfare Undersea Systems, Advanced Development 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 an innovative acoustically transparent mid-frequency SONAR projector to add active capability to traditionally passive sensor arrays and reduce life-cycle costs.

DESCRIPTION: U.S. Navy nuclear attack submarines (SSNs) have traditionally relied on acoustic receive arrays to sense their environment, including sensing of enemy submarines [Refs. 1-2]. Evolving conditions such as increased shipping traffic have degraded the effectiveness of sensing the underwater regime solely using passive acoustic sensors. Mid-frequency active sonar is used extensively by surface combatants and could meet the environmental sensing needs of submarines; however, current projector technology incorporated into submarine arrays would degrade the passive capability that submarines depend on when covert.

Current Navy and commercial state-of-the-art SONAR projectors are physically large and heavy, and require specialty-mounting structures. In addition, such projectors must be mounted at a distance from receive sensors and arrays so as not to interfere acoustically. To add mid-frequency active capability to traditionally passive sensor arrays without degrading passive performance, the Navy requires R&D for an acoustically transparent projector that can be located between or in front of receive sensors and/or arrays. Lifecycle costs will be reduced by eliminating specialty structural and mounting requirements and reducing material, manufacturing, and packaging costs.

Advancements in projector technologies involving meta-materials or non-traditional acoustic signal generation, together with lightweight (such as neutrally buoyant) elements make it feasible to envision acoustically transparent mid-frequency SONAR projector arrays that achieve useful acoustic source levels (SLs) with conventional power amplifiers. The projector and projector cable requirement for acoustic transparency is less than 0.1 dB insertion loss and less than 0.5 degrees phase error induced in individual receive array pressure or velocity sensors. The requirement for mounting location is in front of or in-between receive array elements. Current SONAR projector technologies cannot meet these requirements. Finally, the goal for the associated projector power amplifier is to use existing Navy units such as the Modular Power Amplifier (MPA) or High Density Power Amplifier (HDPA) or ruggedized commercial-off-the-shelf (COTS) devices such as Class D or Class T power amplifiers. Proposed projector concepts shall address the acoustic transparency and mounting location requirements, and the conventional power amplifier goal. The concept shall then provide derived projector performance including, but not limited to, size, weight, mounting/attachment method, transmit voltage response (TVR), useable bandwidth and source level achievable (SL) with selected power amplifier.

Any specialty equipment required, but not normally associated with a submarine environment, shall be identified.  The solution shall also address the environmental requirements associated with submarine use, including but not limited to, temperature (-28°C to 50°C), accelerations (frequencies up to 100 Hz over a range of 0.0 g to 25.0 g), and hydrostatic pressure (depths to 1200 psi). The proposer shall test these parameters at their facilities and may be independently verified at Navy facilities such as the Naval Undersea Warfare Center.

Work produced in Phase II may become classified. Note: The prospective contractor(s) must be U.S. Owned and Operated with no Foreign Influence as defined by DOD 5220.22-M, National Industrial Security Program Operating Manual, unless acceptable mitigating procedures can and have been be implemented and approved by the Defense Security Service (DSS). The selected contractor and/or subcontractor must be able to acquire and maintain a secret level facility and Personnel Security Clearances, in order to perform on advanced phases of this contract as set forth by DSS and NAVSEA in order to gain access to classified information pertaining to the national defense of the United States and its allies; this will be an inherent requirement. The selected company will be required to safeguard classified material IAW DoD 5220.22-M during the advance phases of this contract.

PHASE I: Develop a concept for an innovative acoustically transparent mid-frequency SONAR projector. Demonstrate that the concept can feasibly meet requirements in the Description through modeling and simulation or analysis. The Phase I Option, if exercised, shall include the initial system specifications, models and capabilities description to build a prototype solution in Phase II.

PHASE II: Develop and deliver three innovative acoustically transparent mid-frequency SONAR projector prototypes for testing and evaluation. Demonstrate that the technology meets Navy performance goals for source level, frequency and bandwidth as defined in the Description. Conduct testing and evaluation at a company-provided facility and may be independently verified at a Government facility such as the Naval Undersea Warfare Center. Develop a Phase III plan.

It is probable that the work under this effort will be classified under Phase II (see Description section for details).

PHASE III DUAL USE APPLICATIONS: Support the Navy in transitioning the technology to Navy use for submarine arrays in Integrated Warfare Undersea Systems through system integration and qualification testing. (Note: Government personnel will independently verify test results for the prototype projector, pre-production units, and first article inspection at Navy test facilities prior to Navy use in SONARs aboard submarines.)

Commercial applications that currently utilize various forms of active acoustic transmission and reception that could benefit from lightweight and acoustically transparent projectors include oil exploration, seismic survey, rescue and salvage, and bathymetric survey.


1. Wilson, Oscar B. “Introduction to the Theory and Design of Sonar Transducers.” Peninsula Publishing: Los Altos, CA, 1989.

2. Moffett, M. Trivett, D. Klippel, P. and Baird, P. D. "A Piezoelectric, Flexural-Disk, Neutrally Buoyant, Underwater Accelerometer." IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, Vol. 45, No. 5, 1998, p. 1341.

3. Lindberg, J.F. “The Application of High Energy Density Transducer Materials to Smart Systems.” North Holland: New York, 1981.

4. Sherman, C. H. and Butler, J. L. “Transducers and Arrays for Underwater Sound.” Springer: NY, 2007.

5. “Attack Submarines – SSN.” United States Navy Fact File, 13 Dec 2018.

KEYWORDS: Acoustically Transparent; Mid-frequency SONAR Projector; Eliminate Specialty Mounting Infrastructure; Projector Technology Incorporated into Submarine Arrays; Non-traditional Acoustic Signal Generation; Projector Technologies Involving Meta-materials