Submarine hunting is a complex and vast enterprise, filled with a range of unpredictable variables including the challenge of finding a submarine during the short window of time when it rises to “periscope depth” or lingers just underneath the surface. One tricky aspect is that submarines can also disperse across vast ocean territories to hold ships, land forces and other vital areas at risk of attack. An amphibious assault, for instance, would likely need to clear an attack area of submarines before advancing groups of ships close to shore.
Northrop Grumman is testing some innovations with its helicopter-like FireScout drone which seek to address these kinds of threats by massively expanding the scope and reach of anti-submarine warfare operations. While ship-launched drones can surveil surface areas with cameras, EO/IR sensors can be limited to detect things at various undersea depths, requiring the need for helicopter laser-scanners or sonobuoys. Considering all of these variables and how they intersect with operational complexities, Northrop Grumman maritime engineers begin prototyping sonobuoy dispensers which could be carried by drones to reach much larger amounts of spread-apart ocean areas.
“Submarines are quite a ways apart and you need to put a large amount of buoys in the water. This allows FireScout to go out 100 miles and spend 9-to-12 hours monitoring an area. This puts a bubble out from a ship which a manned helicopter could not search,” Dan Redman, Maritime Mission Expansion Manager, Northrop Grumman, told The National Interest in an interview.
Typically, sonobuoys are dropped by helicopters or surveillance planes such as a Navy P-8 to extend sonar detection beneath the surface, but what about sonobuoy equipped drone platforms able to leverage added endurance, range and dwell time? Northrop Grumman has partnered with Ultra electronics to prototype a new kind of smaller form-factor sonobuoy dispenser which enables the FireScout drone to carry as many as forty sonobuoys on a single mission.
Submarine detection relies upon multiple phases of operations, including search, detect, track and target enemy submarines, all steps which ultimately feed images back into a command and control data system which analyzes the return pings to discern a rendering or shape of a threat object.
Northrop Grumman recently tested this new prototype off the coast of California in a mock-combat scenario to assess its ability to find and discriminate targets.
“We went out and put a field of sonobuoys in the water and had a target and a decoy that was generating the sounds of a submarine,” Redman said.
The new sonobuoy dispenser, which Redman said was about one-half the size of the Navy’s existing thirty-eight-inch dispensers, can be used with a FireScout drone and deploy across wide swaths of ocean.
“It’s half the size and therefore much more compatible for unmanned systems, and we don’t lose a lot of performance,” Redman said.
Kris Osborn is the defense editor for the National Interest. Osborn previously served at the Pentagon as a Highly Qualified Expert with the Office of the Assistant Secretary of the Army—Acquisition, Logistics & Technology. Osborn has also worked as an anchor and on-air military specialist at national TV networks. He has appeared as a guest military expert on Fox News, MSNBC, The Military Channel, and The History Channel. He also has a Masters Degree in Comparative Literature from Columbia University.