Navy approves testing for unmanned minesweeping system

The Unmanned Influence Sweeping System (UISS) will begin developmental testing in the next few months, with plans to place AQS-20 and AQS-24 sonar systems in a similar unmanned surface vehicle to provide electro-optical minehunting capabilities for faster, higher-resolution images, according to Howard Berkof, deputy program manager of Unmanned Maritime Systems at the Navy League’s Sea Air Space exhibition.

The UISS consists of an Unmanned Surface Vehicle (USV) and a minesweeping payload designed for influence sweeping of magnetic, acoustic and magnetic/acoustic combination of mine types.  The UISS payload includes a specialized magnetic cable that tows a modified Mk-104 acoustic device.

“The Mk-104 generates an acoustic source by cavitation and the specialized cable creates an electromagnetic field. The output of these two emitters generates the appropriate fields that satisfy the mine logic so that the mine detonates,” explained Colleen E. O’Rourke, an official at Naval Sea Systems Command (NAVSEA).

In other words, the UISS replicates a ship’s sounds and magnetic signatures to trick mines with influence sensors, which trigger the explosion when they sense a ship, into harmlessly detonating. 

“Currently, [the UISS] is undergoing testing in the South Florida testing facility and is expected to complete its contractor testing here in the next handful of months, and then we’ll transition to government-led developmental testing and, ultimately, operational assessment, before achieving Milestone C in the third quarter of FY 18,” said Berkof.

A follow-on effort to the UISS will leverage the same craft to support minehunting. Specifically, the Navy has plans to integrate both the AQS-20 and AQS-24 towed sonar systems with the Mine Countermeasures (MCM) “truck” USV in the future.

“The UISS program consists of the MCM platform … and when we decide ‘OK, that’s good to go,’ then we start putting different payloads on there,” explained Berkof. The craft in the future is planned to support minehunting, but will be separate from the UISS program. “One is the AQS-20 towed sonar and the other is the AQS-24 towed sonar.”

Though the UISS is a minesweeping system, the AQS-20 and AQS-24 sonar systems are minehunting technologies. According to O’Rourke, “the inherent modularity of the [UISS] USV allows swapping of payloads to change from a minesweeping mission to a minehunting mission.”

“Minehunting and minesweeping are complementary techniques,” explained O’Rourke. “Minehunting employs a sonar to detect, classify and identify mines. The sonar "sees" the mine and localizes it for either neutralization by another MCM system or for avoidance. Influence minesweeping employs systems designed to trigger mine detonation,” she said.

AQS-20 sonar has electro-optical sensors, and can collect exact locational data on undersea mines. According to research conducted by BAE Systems, an industry leader in electro-optical design, electro-optic capabilities can facilitate the use of long-range naval thermal imaging and infrared laser systems, which would likely increase the accuracy and image quality of mine-detection data.

The AQS-24 is currently designed for the MHU Class 2 (small) USV. As of now, Northrop Grumman describes it as the only high-speed surface-towed minehunting system that is operationally proven.

It uses high-speed synthetic aperture radar, which provides a higher resolution by emitting multiple rapid pings at varied frequencies whose data can then be combined to achieve the effect of having a longer sonar array, or aperture, according to the Institute of Electrical and Electronics Engineers.

“The concept is to keep the ship and its sailors out of the mine field and enable unmanned systems to find, identify, and clear mines, so that we can continue our operations and do whatever we need to do in that water way,” explained Berkof.

The UISS is part of the Littoral Combat Ship (LCS) portfolio, which Berkof says is the first class of ship designed from initial construction for unmanned vehicle integration. The next step for the UISS will be testing its launch and recovery from LCS platforms. In the future, the Navy intends to leverage the USV craft to support the minehunting mission.