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Raytheon to upgrade sonar systems in towed mine-hunting remotely operated vehicle

Posted by John Keller

PANAMA CITY, Fla., 2 July 2013. Sonar experts at the Raytheon Co. Integrated Defense Systems segment in Portsmouth, R.I., are upgrading the U.S. Navy AN/AQS-20A mine hunting sonar under terms of a $14.2 million order announced Monday.

Officials of the Naval Surface Warfare Center Panama City Division in Panama City, Fla., are asking Raytheon to upgrade the AN/AQS-20A with a high frequency wideband forward-look sonar and multi-function side looking sonar to improve the system's performance.

The AQS-20A is a sonar-based mine-detection system for helicopters and unmanned underwater vehicles (UUVs) to detect and pinpoint relatively deeply placed anti-ship mines at sea. Sonar is an acronym for sound navigation and ranging.

The system is an underwater towed body with a high resolution, side-looking, multibeam sonar system used for minehunting along the ocean bottom. It provides real-time sonar images to remote operators to help locate, classify, mark, and record mine-like objects and underwater terrain features.

The AQS-20 has an active, stabilized underwater vehicle, equipped with advanced multiple-beam side-looking sonar. When used with aircraft, the helicopter tows the underwater body by a small-diameter electromechanical cable.

An operator aboard the helicopter can view the underwater image and identify objects on a video monitor while recording the data. The system is designed for the Navy MH-60S and MH-53E helicopters, as well as for the AN/WLD-1 remote mine-hunting submersible and for other UUVs.

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The AN/AQS-20A has five separate sonars, and uses imaging sonars, signal processing, and computer algorithms to provide real-time, computer-aided detection and classification of sea mines, Raytheon officials say.

A combination of sidescan, forward-looking, and gap-filler sonars enables the AN/AQS- 20A to detect and classify mine-like objects from the seafloor to the near surface in one pass. The system also has an electro-optics identification capability that delivers high-definition images of bottom mines using Streak Tube Imaging Laser (STIL) technology, Raytheon officials say.

The STIL technology provides the operator with range and contrast data that combines to form a 3-D image during post-mission analysis to aid in mine identification.

The system has four operational modes: single pass shallow (SPS) mode for detecting bottom and moored mines; SINGLE PASS DEEP (SPD) mode for detecting moored mines in deep water; volume mine (VOL) mode for detecting many mines quickly; and identification (ID SPS) mode for detecting bottom and moored mines, plus optical imaging of bottom mines. The AN/AQS-20A also has high-speed data recording for environmental data collection.

On this contract Raytheon will do the work in Portsmouth, R.I., and should be finished in September 2014. For more information contact Raytheon Integrated Defense Systems online at, or the Naval Surface Warfare Center Panama City Division at

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