Applied Physical Sciences Joins STR to Develop Counter-Sonar Technology

The $12.5 million project aims to disrupt and defeat sonar systems on hostile surface warships.

Published on Feb. 24, 2026

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The U.S. Navy has awarded a $12.5 million contract to Applied Physical Sciences Corp. and Systems & Technology Research (STR) LLC to develop innovative payloads that can conduct acoustic warfare to counter active surface sonars. The companies will place these counter-sonar payloads on unmanned underwater vehicles, buoys, moored systems, and other nodes for validation and at-sea demonstrations.

Why it matters

Surface sonar is a critical capability for detecting and tracking submarines, torpedoes, mines, and other underwater threats. This acoustic warfare technology aims to degrade, deceive, or complicate the effectiveness of active surface sonar, providing a strategic advantage against hostile surface warships.

The details

Applied Physical Sciences and STR will develop advanced acoustic hardware, waveforms, and digital signal processing techniques to confound or defeat active sonar detection. The project includes independent verification, hardware-in-the-loop simulations, and at-sea testing to validate the counter-sonar payloads.

  • The Willow program's second phase will involve a sea test to demonstrate three or more nodes to counter enemy surface active sonar systems.
  • Applied Physical Sciences and STR both were participants in Willow phase one, for which contracts were awarded in 2023.
  • The work on this order is expected to be completed by February 2027 for Applied Physical Sciences and January 2027 for STR.

The players

Applied Physical Sciences Corp.

A U.S. company based in Groton, Connecticut that specializes in developing innovative undersea sensor and emitter systems.

Systems & Technology Research (STR) LLC

A technology company based in Woburn, Massachusetts that is partnering with Applied Physical Sciences on the Willow program.

Naval Information Warfare Center Pacific

A U.S. Navy organization based in San Diego that is overseeing the Willow program on behalf of DARPA.

Defense Advanced Research Projects Agency (DARPA)

The U.S. government agency that is funding the Willow program to develop counter-sonar capabilities.

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What’s next

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The takeaway

This project highlights the ongoing technological arms race between surface warships and undersea warfare, as the U.S. Navy seeks to develop new acoustic warfare capabilities to counter the threat posed by enemy surface sonar systems.