TECHNOLOGY AREAS: Sensors, Battlespace

OBJECTIVE: Develop, fabricate, and demonstrate an acoustic transmitter consisting of an underwater acoustic projector, a self-contained very high efficiency power amplifier, signal generation and control circuitry, and a long endurance power supply. An innovative utilization of new transduction technology, integrated power amplification and a novel energy source is desired that can be compact and low cost for operational scenarios and applications that require a specific combination of frequency band, power output, operating depth, and operational life. The primary focus is on the development of low cost transduction technology that can be combined with an innovative power subsystem. The goal is for a new transduction type that can be manufactured at a cost at least 50% less than existing technology.

DESCRIPTION: A low cost, integrated package containing an underwater sonar active transducer, power amplifier and tuning, energy source and appropriate control circuitry is desired for a variety of ASW-related applications. As an example, purely notional, a package could be envisioned for a sonobuoy sized package that operates somewhere in a band encompassing 500 to 1000 Hz and capable of producing a tone with an acoustic output in excess of 50 watts and lasting 500 ping-seconds. The desire is to identify and develop a transduction mechanism that can be used for this specific combination of performance needs and low cost and be capable of being redesigned for different performance needs at higher or lower frequencies, power levels and operational life. For example, an alternative would be a larger transducer at a lower frequency with an output above 100 watts and capable of being part of an array. The innovation desired is the novel mating of transducer, amplifier, and energy source in a potentially low cost assembly that can be seen as a toolkit and further can be seen conceptually as a new class of underwater sonar transmitter.

PHASE I: Identify a 'transduction mechanism/power amplifier/energy source' combination that can be developed to meet a notional need while being inexpensive in both material and fabrication costs. Perform analysis to determine the allocation of 'resources' between and transducer and power amplifier and energy source; i.e., can a cost analysis point toward a combination of of components that delivers the best performance/$ ratio. Undertake 2 or 3 notional paper designs to assess the strength of the approach. Target several ASW scenarios in which these designs can be utilized including those that are volume and weight constrained. Select a design to pursue in Phase II and analyze all aspects of the design and perform a cost analysis for large production.

PHASE II: Complete the design selected in Phase I and fabricate a prototype including transducer, amplifier and energy source. Fabricate and test components separately and then combine to test and assess performance versus prediction. It is possible that the development will lead to an application that will prompt the effort in Phase II to be deemed classified. In addition to the development of the selected prototype, perform a design synthesis to demonstrate the versatility of the overall concept. Based on the cost analysis of the components determine alternates based on performance needs.

Phase I will be UNCLASSIFIED, and the contractor will not require access to any classified data (in other words, if the research outcome relates to applicability to potential transition to systems that involve classified performance requirements, the work itself can be performed using notional requirements that mimic the same level of complexity). Though Phase II work may become classified, the Proposal for Phase II work will be UNCLASSIFIED. If the selected Phase II contractor does not have the required certification for classified work, the related DoN program office will work with the contractor to facilitate certification of related personnel and facility.

PHASE III: Extensively test the prototype(s) fabricated in Phase II and test for severe environmental conditions. Fabricate several other prototypes with differing performance requirements. Do an analysis of cost effects by varying frequency, power, and endurance and determining what performance requirements affect the overall cost. If applicable, place prototype systems in at-sea testing environments.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: The development of this technology will have application to the oceanographic and oil industries in that the ability to have a self-contained, deployable source will enhance the acquisition of data for both oceanographic research and for oil exploration.

REFERENCES:
1. Charles H. Sherman and John L. Butler, Transducers and Arrays for Underwater Sound, Springer, 2007

2. A.D. Waite, Sonar for Practising Engineers, Thomson Marconi Sonar Limited, 1996

3. M.D. McCollum, B.F. Harmonic, O.B. Wilson (Editors), Transducers for Sonics and Ultrasonics, Technomic Publishing, 1993

4. J. Decarpigny, B. Harmonic, O. Wilson, "The Design of Low-Frequency Underwater Acoustic Projectors: Present Status and Future Trends", IEEE J. Oceanic Engineering, Vol. 16. No.1, pp. 107-121 (January 1991)

KEYWORDS: underwater; transducer; sonar; transmitter; projector; low-cost

Questions may also be submitted through DoD SBIR/STTR SITIS website.