Sonobuoy Improvements for Multistatic Active Sonar

Navy SBIR 21.1 - Topic N211-017
NAVAIR - Naval Air Systems Command - Ms. Donna Attick -
Opens: January 14, 2021 - Closes: February 18, 2021 (12:00pm EDT)

N211-017 TITLE: Sonobuoy Improvements for Multistatic Active Sonar

RT&L FOCUS AREA(S): General Warfighting Requirements

TECHNOLOGY AREA(S): Battlespace Environments

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 improvements for active sonar search detection, classification, and localization performance by using or adding non-acoustic sensors to sonobuoys.

DESCRIPTION: Air ASW multistatic active sonar detection, classification, and localization (DCL) performance relies on advanced processing algorithms to exploit transmitted and received sonobuoy signals. The uncertainty surrounding these signals place fundamental limits on system performance and mission success.

The Navy seeks to upgrade or add non-acoustic sensing hardware to sonobuoys which will measurably improve DCL or tracking performance for active sonar (threshold 10% improvement over a sonobuoy without the capability, objective 25% improvement), particularly for scenarios where GPS is not available. An ideal solution will be low cost (adding less than $50.00 to the cost of a production sonobuoy), fit within the existing sonobuoy size (i.e., cylinder of diameter 4 7/8 inches, length 36 inches), weight (i.e., not cause a sonobuoy to exceed a maximum of 39 lbs) and power (SWaP) constraints (ideally a sensor requiring less than 12 volts and 25 milliamps), and be capable of improving several performance metrics.

Proposed solutions should identify the sonobuoy(s) to be upgraded, the performance metrics expected to benefit from the proposed sensor hardware improvements, and quantify the expected improvement through simulation and/or experiments. Sonobuoy improvements may consider adding transducers and/or replacing existing ones. Examples of such include, but are not limited to, buoy localization performance could potentially be improved by adding/replacing sensors to increase accuracy of time-of-flight and/or bearing measurements. Temperature and/or salinity sensors could be added to provide a partial sound speed profile for individual buoys. Sensors such as inertial measurement units (IMU), gyroscopes, and accelerometers could be used for motion compensation.

Work produced in Phase II may be classified. Note: If the work is classified then, 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 and Security Agency (DCSA) formerly 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 project as set forth by DCSA and NAVAIR 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 advanced phases of this contract.

PHASE I: Demonstrate feasibility of the proposed concept through analysis, simulation, and real-world measurements where possible. Analysis should include estimating the bounds of performance for the proposed method, and potential impacts to the existing sonar system operation. Conduct trade-offs of SWaP versus performance improvements for different sensing strategies. The Phase I effort will include prototype plans to be developed under Phase II.

PHASE II: Refine the concept and develop prototype sonobuoys with improved sensing. Evaluate the improvements using at sea experiments. Develop processing software for using the new sensors either aboard an aircraft or embedded in the sonobuoy.

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: Finalize and implement the capability into a sonobuoy that can be deployed in an open ocean environment during a data gathering event conducted by the Navy. Analyze the data collected in this real-world environment event and verify that the realized gains in performance matched the expected gains.

The technology developed under this effort has application across the Navy for sonar, radar, electro-optic, magnetic anomaly detection and other sensor devices. Any commercial application that uses sensors whose positions need to be known with more precision would benefit from this effort. A possible commercial application could include improved sensor positions during medical imaging procedures.


  1. Reynolds, S.A.; Flatté, S.M.; Dashen, R.; Buehler, B. and Maciejewski, P. "AFAR measurements of acoustic mutual coherence functions of time and frequency." The Journal of the Acoustical Society of America, 77(5), May 1985, pp. 1723-1731.
  2. Kirk, J.C. "Motion compensation for synthetic Aperture Radar." IEEE Transactions on Aerospace and Electronic Systems, AES-11(3), May 1975, pp. 338-348.
  3. Hayes, M.P. and Gough, P.T. "Synthetic aperture sonar: A review of current status." IEEE Journal of Oceanic Engineering, 34(3), July 2009, pp. 207-224.
  4. "DoD 5220.22-M National Industrial Security Program Operating Manual (Incorporating Change 2, May 18, 2016)." Department of Defense.

KEYWORDS: sensor position; position uncertainty; sonobuoy positions; sensor movement compensation; Detection, Classification, Localization; DCL; sonar sensors; sonobuoy


The Navy Topic above is an "unofficial" copy from the overall DoD 21.1 SBIR BAA. Please see the official DoD Topic website at for any updates.

The DoD issued its 21.1 SBIR BAA pre-release on December 8, 2020, which opens to receive proposals on January 14, 2021, and closes February 18, 2021 at 12:00 p.m. ET.

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