Navy Ship-Launched Drones Might Massively Expand Sub-Hunting With New Sonobouys
Video: Army Research Lab Scientist Describes Human Brain as Sensor Connecting With AI
by Kris Osborn - Warrior Maven
(Washington D.C.) Submarine hunting is a complex and vast enterprise, filled with a range of unpredictable variables to include the challenge of finding one during the short window of time when it rises to “periscope depth” or lingers just underneath the surface. They 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.
Sonobuoy-equipped MH-60R helicopters launched from amphibious assault ships can search for submarines within a certain reachable radius of its host ship, depending their range and mission endurance, yet the scope of the search is of course limited by the constraints of any manned air platform.
However, what about launching drones armed with 40 sonobuoys across wide swaths of open ocean to greatly expand the operational envelope of any Navy submarine hunting mission? This kind of operational possibility changes the mission sphere for anti-submarine warfare as it supports the possibility of more disaggregated or dispersed operations, something of great relevance given the service’s emphasis upon migrating quickly toward its Distributed Maritime Operations strategy.
Northrop Grumman is testing some innovations of 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 of course 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 40 sonobuoys on a single mission.
Submarine detection of course relies upon multiple phases of operations to include 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 of the Navy’s existing 38-inch dispensers, can load up 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.
The concept began by envisioning a tactical circumstance wherein ship-launched drones could redefine the reach of sub-hunting missions by prototyping smaller, drone-carried sonobuoy dispensers, Northrop Grumman engineers sought to architect and apply new technology to actualize the Navy’s DMO strategy. The idea is to combine signal input from a large number of dispersed and otherwise disconnected sonobuoy hydrophone antennas on the surface.
The principle aim, which Northrop Grumman innovators recently tested off the coast of California, is to disperse large numbers of smaller sonobuoy dispensers across otherwise unreachable swaths of ocean to extend the Navy’s submarine-hunting reach and collect or pool otherwise disparate individual return signals into a centralized or collective communications processing hub.
“A drone can go out and do preliminary searches and, when and if needed, cue a manned platform to certain high-value areas where a return ping might be arriving,” Dan Redman, Maritime Mission Expansion Manager, Northrop Grumman, told The National Interest in an interview.
Northrop Grumman photo
A sonobuoy is descended beneath the surface of the ocean and, once an acoustic return signal or “ping” is detected by an undersea transducer, data is then sent up to a hydrophone buoy floating on the surface which then transmits crucial information back up to a helicopter or command and control aircraft using a VHF antenna kit.
The technical concept not only involves a smaller form factor and wider distribution but a multi-static or multi-directional pinging which seeks to gather or pool incoming signals from a number of otherwise separated or disaggregated sonar nodes.
“The hydrophone is constantly transmitting through a VHF frequency to an airplane or helicopter where the data gets processed. Multi-static means many receivers feed into a central hub,” Redman explained.
Redman explained that the new technology builds upon some cutting edge systems.
“The technology already exists with manned systems. We have been working on a different design and integrating it into an unmanned system. We are trying to be forward-thinking so we are ready for the Navy,” 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.