Safe Alternatives to Active Sonar That Are In Use or Development by the US Navy Now

1. Passive Sonar

In warfare, passive sonar has the advantage of not betraying the presence of the listener.

IUSS (Integrated Undersea Surveillance System)

  • FSS (Fixed Surveillance System)
  • FDS (Fixed Distributed System)
  • ADS (Advanced Deployable System)

Passive sensor systems, either stationary or dropped quickly in tactical locations, with real-time digital data links into military command/control networks.

Multi-Line Array Systems

  • SURTASS Twin-Line: Twin towed array lines resolving contact direction and improving resolution.
    Surveillance Towed Array Sensor System (SURTASS) Twin Line operations in 1998 and 1999 demonstrated the ability to detect advanced diesel submarines at substantial ranges in the littoral environment where contact was previously thought to be unobtainable by the operational commander.” Statement of RADM Malcom I Fages, US Navy Director, Submarine Warfare Division, Office of the Chief of Naval Operations and RADM JP Davis, US Navy Program Executive Office for Submarines, before the House Armed Services Committee Military Procurement Subcommittee on Submarine Force Structure and Modernization 27 June 2000.
  • VLA (Vertical Line Arrays): Stationary multiple array lines achieving significant gains in resolution and signal to noise.
  • TB-29 submarine-towed (twin, triple): Multiple towed lines at depth resolve contact solutions dynamically.
  • Sonobuoy Arrays in real-time radio linked networks.

RPS (Robust Passive Sonar)

DARPA funded program achieving increased sonar performance by a factor of 10 using:

  • Multiple sensor arrays
  • Advanced Signal Processing
  • AMFP (Adaptive Match Field Processing): Santa Barbara Channel Experiment, year 2000.
  • RR-AMFP: Rank Reduction Processing improves AMFP signal to noise ratios an order of magnitude.

A-RCI and other Advanced Signal Processing

Increased sonar systems processing power using:

  • COTS (commercial-off-the-shelf) Hardware components.
  • Advanced Signal Processing Software components.

2. Non-acoustic Sensors


Silently detects temporal magnetic anomalies such as submarine hulls. Limited range.

Satellite imaging:

Satellite imaging analysis reveals submarine trails and water disturbances. Limited use.

3. Integrated Sensory Networks

  • Advanced correlative processing of complementary sensor systems.
  • GCI: Geologic Clutter Initiative: digitally characterize the littoral landscape to improve sonar operations.


Prepared for the Ocean Mammal Institute by Robert W. Rand, INCE

Contact: Marsha L. Green, PhD, – Ocean Mammal Institute

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