N221-011 TITLE: Low-Cost, Large, Multidimensional, High-Sensor-Density, Collapsible Arrays

OUSD (R&E) MODERNIZATION PRIORITY: General Warfighting Requirements (GWR)

TECHNOLOGY AREA(S): Electronics

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 large, multidimensional, high-sensor-density, collapsible arrays compatible with A-size sonobuoy dimensions and applications.

DESCRIPTION: The Navy requires high-gain arrays for both passive and active sonar due to continued submarine quieting. Technically, this implies designs with increased apertures, dimensionality, and numbers of elements. However, the fundamental constraint of an A-size sonobuoy will remain in place for the foreseeable future. Traditional sonobuoys have evolved from single-line, multi-element arrays to more complex two-dimensional planar arrays (e.g., the Air-Deployable Acoustic Receiver (ADAR)). Rather than seeking an incremental path of increasing the efficiency of discrete element foldable structures, this SBIR topic seeks radical new solutions for achieving high-gain, three-dimensional, multi-element array structures capable of fitting within an 18 in. length and 4.75 in diameter section of an A-size sonobuoy. Of interest, but not required, is the use of collapsible, water-inflatable structures or novel material methods to create a structural framework. The solution should then enlist techniques to maximize use of the array�s structure to support stable sensing elements of high density. The over-sampled volumetric array should increase array gain, increase flexibility in controlling sidelobes, and increase adaptivity across operating bands. Efficiency in electrical connectivity (if needed), power use, stability of the structure when deployed, sensitivity of the elements, and overall weight are important design factors to consider as well. The overall goal of this topic is to identify and implement technology that incorporates novel mechanical and sensor designs to exploit as much of the array�s structure as possible to greatly increase sonobuoy sensing capability.

The performance objectives:

• Packaged size: < 18 in. (45.72 cm) of the A-size canister
• Numbers of elements: > 100
• Element frequency response: up to 7.5 kHz
• Sensitivity�Noise: limited sea -state zero (SS0) noise
• Weight: < 20 lb (9.07 kg)

PHASE I: Develop a conceptual design for a volumetric array. Since there is no physical aperture requirement, demonstrate the feasibility of the design relative to an existing A-size sonobuoy aperture and expected performance estimated from open sources. Identify technological and reliability challenges of the design and propose viable risk mitigation strategies. The Phase I effort will include prototype plans to be developed under Phase II.

PHASE II: Develop a specific set of sonobuoy array requirements satisfying critical mission(s) needs. Adapt the Phase I conceptual design to satisfy those requirements. Then design, fabricate, and deliver an array subsystem prototype capable of meeting the requirements. Test and fully characterize the system prototype.

PHASE III DUAL USE APPLICATIONS: Adapt the Phase II design into existing A-size sonobuoy architecture(s); designing, fabricating, and delivering a sonobuoy prototype capable of meeting the requirements; test and fully characterize the system prototype.

The development of this technology will have application to the oceanographic community and oil exploration industry.

REFERENCES:

1. Suhey, J. D., Kim, N. H., & Niezrecki, C. (2005). Numerical modeling and design of inflatable structures�application to open-ocean-aquaculture cages. Aquacultural Engineering, 33(4), 285-303. https://doi.org/10.1016/j.aquaeng.2005.03.001.
2. Budynas, R. G., & Nisbett, J. K. (2015). Shigley's Mechanical Engineering Design. New York: McGraw-Hill. https://www.amazon.com/Shigleys-Mechanical-Engineering-Richard-Budynas/dp/933922163X.
3. Holler, R.A., Horbach, A.W., & McEachern, J.F. (2008). The Ears of Air ASW � A History of U.S. Navy Sonobuoys. Navmar Applied Sciences Corporation. https://www.worldcat.org/title/ears-of-air-asw-a-history-of-us-navy-sonobuoys/oclc/720627294.

KEYWORDS: Sonobuoy; Array; ASW; Collapsible; A-size; Structure