The Navy has taken a step forward in deploying a new mine-detection sensor platform. The helicopter-borne array should give operators a way to glean situational awareness around nautical mines from a safe stand-off distance.
The Navy recently announced initial operational capability for the AN/AES-1 Airborne Laser Mine Detection System, or ALMDS. Mounted on MH-60 helicopters, the system delivers rapid wide-area assessment of mine threats in sea lanes, littoral zones, confined straits, choke points and amphibious areas of operations.
This latest development supports the Navy's ongoing effort to get smarter and more efficient about mine detection at sea.
"Our primary hunting, sweep and neutralization systems must be replaced with new technologies that will do the time consuming, dangerous, and dirty work," Maj. Gen. Christopher Owens, director of expeditionary warfare, said in a Navy news release.
Northrop Grumman Corporation says it has delivered 15 of 38 systems to the Navy, and the deployment among littoral combat ships will begin this year.
"This will help us validate our concept of operations and tactical integration — providing system feedback that will allow us to refine software and techniques that will reduce the time needed to conduct post-mission analysis and system upkeep," Owens said.
ALMDS has been a long time coming. It went into low-rate initial production in 2005, and in mid-2010, it saw successful operational testing at Naval Surface Warfare Center Panama City. The system passed operational testing on the MH-60S helicopter in 2012. In 2014, Helicopter Sea Combat Squadron (HSC) 26, Detachment 2, Laser Hawks, began the operational testing and demonstration of ALMDS for the 5th Fleet on the system’s maiden deployment.
"The U.S. Fifth Fleet is focused on reducing the threat posed by sea-based mines in the region should that be necessary and the presence of ALMDS here in the theater adds to our capacity to do just that," Vice Adm. John W. Miller, commander of U.S. Naval Forces Central Command, U.S. 5th Fleet, Combined Maritime Forces said in a news release at the time. "The international community has a critical shared interest in the free flow of commerce in this region. ALMDS, along with the many other counter-mine systems we operate in the Fifth Fleet, allows the Navy to keep the sea lanes open."
Attached to a standard Bomb Rack Unit 14 mount, the system incorporates nine sub-systems including a laser transmitter, a power distribution unit and four received sensor assemblies. This system uses streak-tube imaging and light detection and ranging to detect, classify and localize floating and near-surface moored mines.
"This provides a highly reliable, capable, affordable and fast way of finding and detecting minelike objects," said Mark Skinner, vice president of Northrop Grumman’s directed energy programs.
"It also is a very safe way to do it because it keeps the sailor out of the minefield. In the past we’ve used mine hunters and minesweepers. We’ve towed sleds, and sometimes we just run into them," he said.
The pod is designed for plug and play use. It fits in the standard MH-60 rack configuration and can be easily swapped out for other sensor devices. "If you have a couple of helicopters aboard a ship, they can configure the helo to do a mine detection mission and then easily reset to go out and do another mission," Skinner said.
"Every captain wants a modular, flexible approach to war fighting so that he can configure his ship based on whatever threat he encounters. They have to be able to very rapidly configure and deploy those air assets," he said.
From a technical point of view, developers had to contend with the complexities of trying to accurately aim a laser through moving water and retrieve the corresponding signal. This took some engineering creativity.
"The key thing is that any time you cross a significant interface in nature, you are going to have a hard problem," Skinner said.
Diffraction can occur as signal passes between air and water. "You also have to deal with the sea state. You have to take on turbidity and salinity in the water column. There may be biologic objects. Then it has to be reflected back through all of that and be captured on a receiver on a moving helicopter," he said.
The mission posed operational challenges as well. "When you’re looking for a small mine in a big space of water, what’s the best way to position that detector? You can point the laser straight down into the water column, or you can tilt it," Skinner said. "There are so many variables like that."
Looking ahead, the manufacturer aims to glean data from initial deployments in the hopes of making further refinements.
"We know the Navy is not shy about lessons learned, so we are eager to get that feedback from the junior operators out there flying those helicopters. We think we know how we can improve the system even further, but the fleet hasn’t weighed in yet. We’re looking forward to that," Skinner said.
