Long-Range Acoustic Communications System

Navy SBIR 23.1 - Topic N231-036
NAVSEA - Naval Sea Systems Command
Pre-release 1/11/23   Opens to accept proposals 2/08/23   Closes 3/08/23 12:00pm ET

N231-036 TITLE: Long-Range Acoustic Communications System


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 a long-range acoustic communications system that supports paging submerged unmanned autonomous systems operating in deep- and shallow-ocean environments.

DESCRIPTION: The Navy is seeking to develop a long-range acoustic communications system capable of transmitting service-requests, alerts, and coordination messages to unmanned systems operating in deep and shallow ocean environments. The development of a long-range communications system to support unmanned maritime system operations in which both transmitter and receiver are submerged is challenging due to the size, weight, and power (SWaP) constraints imposed by most battery powered unmanned vehicles, and the impact of environmental properties on the characteristics of the acoustic channel. Due to the increase in absorption losses that acoustic signals undergo as their frequency increases, long-range acoustic-communication system must use low frequency bands and require an acoustic source with high electro-acoustic efficiency able to reach source levels above 190 dB re 1 microPa [Ref 5]. The commercial market and most state-of-the-art research on underwater acoustic communications have focused on increasing the transmission bit rate for short and medium range point-to-point applications. Some commercially-available long-range acoustic messaging systems integrate radiofrequency (RF) communications with an RF/acoustic surface gateway to reach undersea nodes from a surface station. Similar systems for submerged source and destination pairs that do not require surface relay infrastructure are not commercially available.

To address this gap, the long-range acoustic communications system proposed under this SBIR topic must be, at a minimum, capable of transmitting one-way through water to enable asymmetric acoustic communications at ranges up to 100 km in shallow ocean waters and up to 200 km in shallow-to-deep ocean waters. Shallow-water acoustic propagation environments featuring both upward-refracting and downward-refracting sound speed profiles can be considered. The transmitter should cover conical volumes with tunable apertures between 5 and 25 degrees. The communications system must transmit messages up to 125 bytes (uncoded) on a 12-hour cycle, and bursts of messages up to 64 bytes as needed. Additionally, the system must be robust to Doppler effects for relative transmitter-receiver speeds of up to 5 m/s. If a surface receiver is used, it must be able to receive acoustic messaging with minimal performance degradation at up to sea-state level 8 (based on Beaufortís wind-force scale). In general, the communications system must be robust to small-scale variability in acoustic channel conditions. Finally, modulations and waveforms with low-probability-of-detection and low-probability-of-interception characteristics would be preferred.

The communications receiver is required to have a form factor capable of fitting within a medium-size UUV with a cylindrical shape not to exceed 12" radius and 10" length. The system including electronics, transducers or other transmitter/receiver hardware must weigh less than 5 lbs. SWaP constraints on the acoustic transducer geometry imposed by UUV configurations will drive the level of asymmetry expected in the long-range acoustic communication links enabled by the communications system. Similar SWaP guidelines apply to the transmitter module if deployed in a UUV. A power allowance of 200 W for transmit mode and 10 W for receive mode should be used as a design reference-power-budget for medium class UUVs. Deployment of a transmitter for larger platforms, both mobile and fixed, will also be considered. In the latter case, SWaP guidelines will be adjusted to the target platform.

To ensure interoperability with planned and future UUVs, solutions must also comply with the PMS 406ís Unmanned Maritime Autonomy Architecture (UMAA). UMAA establishes a standard for common interfaces and software reuse among the mission autonomy and the various vehicle controllers, payloads, and C2 services in the PMS 406 portfolio of Unmanned surface and undersea vehicles (UxV). The UMAA standard for Interface Control Documents (ICDs) mitigates the risk of unique autonomy solutions applicable to just a few vehicles allowing flexibility to incorporate vendor improvements as they are identified; affect cross-domain interoperability of UxS vehicles; and allow for open architecture (OA) modularity of autonomy solutions, control systems, C2, and payloads. UMAA standards and required ICDs will be provided during the Phase I effort.

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 implemented and approved by the Defense Counterintelligence Security Agency (DCSA), formerly the Defense Security Service (DSS). The selected contractor must be able to acquire and maintain a secret level facility and Personnel Security Clearances, to perform on advanced phases of this contract as set forth by DCSA and NAVSEA 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.

All DoD Information Systems (IS) and Platform Information Technology (PIT) systems will be categorized in accordance with Committee on National Security Systems Instruction (CNSSI) 1253, implemented using a corresponding set of security controls from National Institute of Standards and Technology (NIST) Special Publication (SP) 800-53, and evaluated using assessment procedures from NIST SP 800-53A and DoD-specific (KS) (Information Assurance Technical Authority (IATA) Standards and Tools).

The Contractor shall support the Assessment and Authorization (A&A) of the system. The Contractor shall support the governmentís efforts to obtain an Authorization to Operate (ATO) in accordance with DoDI 8500.01 Cybersecurity, DoDI 8510.01 Risk Management Framework (RMF) for DoD Information Technology (IT), NIST SP 800-53, NAVSEA 9400.2-M (October 2016), and business rules set by the NAVSEA Echelon II and the Functional Authorizing Official (FAO). The Contractor shall design the tool to their proposed RMF Security Controls necessary to obtain A&A. The Contractor shall provide technical support and design material for RMF assessment and authorization in accordance with NAVSEA Instruction 9400.2-M by delivering OQE and documentation to support assessment and authorization package development.

Contractor Information Systems Security Requirements. The Contractor shall implement the security requirements set forth in the clause entitled DFARS 252.204-7012, "Safeguarding Covered Defense Information and Cyber Incident Reporting," and National Institute of Standards and Technology (NIST) Special Publication 800-171.

PHASE I: Develop a concept for a long-range acoustic communications system that meets the requirements in the Description. Establish feasibility by developing system diagrams as well as Computer-Aided Design (CAD) models that show the transmitter concept and provide estimated weight and dimensions of the concept. Feasibility will also be established by computer-based simulations that show the systemís capabilities are suitable for the project needs. The hardware design shall include an assessment of the SWaP for the acoustic transmitter and receiver, as well as a notional transducer geometry that accommodates the space constraints imposed by medium-size UUVs. The Phase I Option, if exercised, will include the initial design specifications and capabilities description to build a prototype solution in Phase II.

PHASE II: Based on the results of Phase I and the Phase II Statement of Work (SOW), develop and deliver a prototype system for in-water testing and measurement/validation of the Phase I performance attributes. The system prototype shall include a transmitter receiver pair, and the corresponding software and application programming interface (API) descriptions. Test the prototype system, first in a controlled laboratory environment, then in an in-water (saltwater) environment, to determine its capability to meet all relevant performance metrics outlined above and in the Phase II SOW. Performers are expected to explore opportunities for at-sea experimentation to further demonstrate the feasibility of the system. Demonstrate the prototype system performance in both environments (laboratory and in-water) and present the results in two separate test reports to the Government. Use the results to correct any performance deficiencies and refine the prototype into a pre-production design that will meet Navy requirements. Prepare a Phase III SOW that will outline how the technology will be transitioned for Navy use.

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: The company will support the Navy in transitioning the technology to Navy use. Work with Navy subject matter experts to develop an acoustic communications system for UUVs.

If successful, the long-range acoustic communications system could be applied to other unmanned Navy assets including buoys and subsea nodes. These assets have communications requirements, some of which require covert communications for which this system could provide a solution. In addition to such DoD applications, the communication system could be used in commercial oil, gas, and oceanographic sensing applications.


1.       Rodionov, P. Unru and A. Golov, "Long-Range Underwater Acoustic Navigation and Communication System," proc. of IEEE Eurasia Conference on IOT, Communication and Engineering (ECICE), 2020, pp. 60-63. https://ieeexplore.ieee.org/document/9301970

2.       J. Huang and R. Diamant, "Adaptive Modulation for Long-Range Underwater Acoustic Communication," in IEEE Transactions on Wireless Communications, vol. 19, no. 10, pp. 6844-6857, Oct. 2020. https://ieeexplore.ieee.org/document/9137713

3.       R. Diamant and L. Lampe, "Low Probability of Detection for Underwater Acoustic Communication: A Review," in IEEE Access, vol. 6, pp. 19099-19112, 2018. https://ieeexplore.ieee.org/document/8322231

4.       L. Freitag, K. Ball, J. Partan, P. Koski and S. Singh, "Long range acoustic communications and navigation in the Arctic," OCEANS 2015 - MTS/IEEE Washington, 2015, pp. 1-5. https://ieeexplore.ieee.org/document/7401956

5.       Mosca F, Matte G, Shimura T. Low-frequency source for very long-range underwater communication. J. Acoust. Soc. Am. 2013 Jan; 133(1): EL61-7. https://asa.scitation.org/doi/10.1121/1.4773199


KEYWORDS: Underwater acoustic communication systems; long-range underwater acoustic communications; assured underwater C2; Secure underwater acoustic communications; adaptive modulation; channel estimation and equalization.

TPOC-1: Pedro Forero

Phone: (619) 553-2670

Email: [email protected]


TPOC-2: Dusan Radosevic 

Phone: (619) 553-6736

Email: [email protected]


The Navy Topic above is an "unofficial" copy from the Navy Topics in the DoD 23.1 SBIR BAA. Please see the official DoD Topic website at www.defensesbirsttr.mil/SBIR-STTR/Opportunities/#announcements for any updates.

The DoD issued its Navy 23.1 SBIR Topics pre-release on January 11, 2023 which opens to receive proposals on February 8, 2023, and closes March 8, 2023 (12:00pm ET).

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