N252-090 TITLE: Second Order Acoustic Vector Sensors

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Integrated Network Systems-of-Systems;Integrated Sensing and Cyber;Microelectronics

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 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 and demonstrate an increase in acoustic performance via second order vector sensors for use in advanced sonobuoy arrays to track and localize stealthier targets within a larger search area to increase success in future U.S. naval anti-submarine warfare operations.

DESCRIPTION: The application of second order acoustic sensors is employed to great effect in commercial acoustic products such as hearing aids. The U.S. Department of the Navy seeks to explore the application of similar second order directional receivers in sonobuoys to increase overall system performance in air Anti-Submarine Warfare (ASW) operations.

Historically, sonobuoys utilized a variety of approaches to achieve first order directional channels, including acceleration, pressure gradient, and multi-mode sensors. The main advantage of a higher order directional acoustic channel is increased directivity index, which also results in a more complex beam pattern compared to the conventional first order channel. Together, these attributes provide an opportunity to increase overall array gain in complex real-world acoustic environments.

The advantages offered by higher order directional receive channels are fundamentally enabled by increasing the number of receiving channels and then combining them in a beamformer based on the expected acoustic propagation for the sensor configuration. As is true in most acoustic products, sonobuoys must balance these potential performance gains against the targeted unit production cost and limited available volume. Other challenges such as build variances, channel self-noise level, and signal processing power consumption must be addressed to form higher order directional channels. This SBIR topic is interested in developing equally spaced vertical line arrays of second order vector sensors with a center frequency at 1000Hz and a bandwidth of 400 Hz, and with a center frequency at 8kHz and a bandwidth of 1.5kHz. This SBIR topic will determine the number of second order vector sensors that can be packaged in an A-size sonobuoy. The self-noise of each individual second order cardioid will be equal to or less than 30 dB. The array self-noise will be reduced by 10 log of N where N is the number of elements in the array. Approaches must allow for continuous beam steering in in azimuth.

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 32 U.S.C. § 2004.20 et seq., National Industrial Security Program Executive Agent and Operating Manual, unless acceptable mitigating procedures can and have been implemented and approved by the Defense Counterintelligence and Security Agency (DCSA) formerly Defense Security Service (DSS). The selected contractor must be able to acquire and maintain a secret level facility and Personnel Security Clearances. This will allow contractor personnel to perform on advanced phases of this project as set forth by DCSA and NAVAIR 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 during the advanced phases of this contract IAW the National Industrial Security Program Operating Manual (NISPOM), which can be found at Title 32, Part 2004.20 of the Code of Federal Regulations.

PHASE I: Develop, design, and demonstrate feasibility of candidate second order directional sensor configurations and associated beamforming approaches that offer performance advantages for sonobuoys in one or more aspects of the overall air-ASW mission. Predict overall performance and offer mitigations to various design challenges. Compare the candidates and down select to a notional design to build and test in Phase II. Demonstrate that chosen candidates can eventually be scaled to fit into an A-size sonobuoy package with considerable effort.

Perform in-depth modelling during the study and identification of possible candidates. Conduct some initial testing to demonstrate the raw material and/or hardware needed to build the candidates for Phase II possess the characteristics used for modeling or that at least the component has the characteristics and performance required for the system to achieve the objectives.

The Navy seeks proven candidate(s) that have been demonstrated and validated to meet the objectives and can be scaled down to fit within the A-size constraints. The small business awardee must provide a full report where their models have been performed with sufficient accuracy and depth to produce meaningful results to meet the objectives. In addition, demonstrate that preliminary testing has been performed on the raw material and/or hardware showing that it possesses the characteristics used for modeling, or that at least the component has the characteristics and performance required for the system to achieve the objectives. The small business awardee must also prove the models and results provided in the report were originated by them.

The Phase I effort will include prototype plans to be developed under Phase II.

PHASE II: Develop and test prototype(s) of the second order vector sensor to verify Phase I performance predictions. Quantify key performance metrics through a combination of laboratory and open water testing. Extrapolate the expected performance for the intended mission(s).

Work in Phase II may become classified. Please see note in Description paragraph.

PHASE III DUAL USE APPLICATIONS: Integrate the second order vector sensor technology into an A-size sonobuoy, leveraging the prototype fabricated in Phase II. Conduct a demonstration and characterize mission performance under real world conditions.

The new approaches developed in this SBIR topic could enhance acoustic sensing technologies for harbor and port security, marine conservation, and other research or monitoring applications.

REFERENCES:

1. Bentler, B. A. and Kruger, B. "Clarifications of some hearing aid terminology: bands and channels versus handles; first-order versus second-order microphones." Acoustics Today, July 2009. https://acousticstoday.org/clarification-of-some-hearing-aid-terminology-bands-and-channels-versus-handles-first-order-versus-second-order-microphones-ruth-a-bentler/
2. Cox, H. and Lai, H. "Performance of Line Arrays of Vector and Higher Order Sensors." 2007 Conference Record of the Forty-First Asilomar Conference on Signals, Systems and Computers, Pacific Grove, CA, USA, 2007, pp. 1231-1236. doi: 10.1109/ACSSC.2007.4487422
3. Sherman, C. H. and Butler, J. L. "Transducers and Arrays for Underwater Sound." Springer New York, 2007. doi: 10.1007/978-0-387-33139-3
4. D’Spain, G. L.; Luby, J. C.; Wilson, G. R. and Gramann, R. A. "Vector sensors and vector sensor line arrays: Comments on optimal array gain and detection." The Journal of the Acoustical Society of America, vol. 120, no. 1, July 01, 2006, pp. 171-185. doi: 10.1121/1.2207573
5. Cray, B. A.; Evora, V. M. and Nuttall, A. H. "Highly directional acoustic receivers." The Journal of the Acoustical Society of America, vol. 113, no. 3, February 28, 2003, pp. 1526-1532,. doi: 10.1121/1.1543851
6. "National Industrial Security Program Executive Agent and Operating Manual (NISP), 32 U.S.C. § 2004.20 et seq. 1993." https://www.ecfr.gov/current/title-32/subtitle-B/chapter-XX/part-2004

KEYWORDS: Undersea sensor; Acoustic; Vector sensor; Second order beamforming; Sonobuoy; Arrays

TPOC 1: Angel Astacio Echevarria
(301) 342-0749
[email protected]

TPOC 2: Don Russo
(301) 342-2048
[email protected]

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