Model 980 Active Low-Frequency Towed Sonar (ALOFTS) by Harris Corporation

Companies & Organizations:

United States of America

Harris Corporation
1025 W NASA Boulevard
Melbourne, FL 32919

The Harris Active Low-Frequency Towed Sonar or ALOFTS provides long, medium and short-range detection, localization, classification and tracking of submarines in blue and littoral water environments.


Detection and tracking are provided for both active and passive operations


ALOFTS combines a proven active acoustic source in a variable depth body with an attached towed array to receive active sonar signals. The towed array also provides a full passive sonar capability. Shipboard processing equipment is implemented with the most modern state-of-the-art COTS processing and telemetry electronics. The system includes a torpedo detection capability for self-defense purposes. Automatic detection and tracking are provided for both active and passive operations, greatly reducing operator workload.


Harris Towed Sonar Performs in Littoral, Shallow Water Environments


The towing and handling system combines the VDS and passive towed array to achieve a single "short scope" tow, which provides rapid response to ship maneuvers and is effective in the littoral, shallow water environment where other towed arrays are ineffective. System features for handling the VDS/towed array during towing operations include remote depth control from the sonar operator's console, automatic depth keeping and automatic bottom avoidance capabilities.


Determine contact bearing without complex triplet or multiple towed arrays


Port/Starboard ambiguity is resolved utilizing a directional transmission scheme, which has been successfully demonstrated at sea in various U.S. Navy tests. This allows unambiguous determination of target bearing without the need for complex triplet or multiple towed arrays.


Technical specifications:


System Features

High speed tow: 22 knots operational, 30 knots survivable

Directional transmission

Embedded high fidelity trainer

Automatic depth keeping

Automatic bottom avoidance

Short scope tow

Small/large ship configurable - 1⁄2 the weight of comparable systems

Simultaneous active and passive operation

Simultaneous CW and FM processing

Proven tow body

High capacity recording system

Port/starboard ambiguity resolution

Multitarget tracking

Open systems architecture

Torpedo detection

Embedded XBT/Performance Prediction system



Display Features

Active 360° search

Active sector search

Active classification (3-D display)

Tactical geographic display

Built-in test reporting

Performance prediction

Passive classification (DEMON)

Passive broadband search and track



Resulting Capabilities

Long-range detection

Left/right ambiguity resolution

Reverberation reduction

Flow noise minimization at high speed



Open systems architecture

Single tow active and passive sonar detects, classifies and localizes below layer threats

Torpedo defense and optional countermeasures

Intuitive user interface

High speed towing

Configurable for small and large ships

Port/Starboard ambiguity resolution

Full azimuth coverage in broadband and narrowband

Defense Products & Services: Model 980 Active Low-Frequency Towed Sonar (ALOFTS) by Harris Corporation
Companies & Organizations: 
Defense Products & Services Sectors: Sonars, towed array
Description: Model 980 Active Low-Frequency Towed Sonar (ALOFTS)
Source of Information: Harris Corporation