By Kris Osborn - Warrior Maven

(Washington D.C.) Sub-hunting spy planes armed with torpedoes, maritime drones armed with missiles, high-resolution, surface scanning cameras, and fast-moving surface ships dragging sonar sensors while conducting surface reconnaissance are all fast-growing threats to U.S. Navy submarines.

Part of the challenge is finding ways to minimize Navy submarine vulnerability to enemy detection and attack by simply remaining at safer depths, yet in order to achieve a high-degree of high-speed connectivity, submarines need to break the ocean surface by coming to “periscope depth,” which is closer to the surface.

The U.S. Navy is working with a number of industry partners such as Northrop Grumman to identify, evolve and refine new kinds of undersea communications technology.

“Today, the submarine comes to periscope depth and conducts the majority of its transmissions at this depth. Capabilities we’re developing at Northrop Grumman will allow the submarine to never have to come up to the surface, because it is at its most vulnerable when at periscope depth,” Alan Lytle, vice president of Strategy & Mission Solutions, Maritime/Land Systems & Sensors division, Northrop Grumman, told The National Interest in an interview.

Interestingly, while most people might immediately associate Northrop Grumman with high-profile programs such as its B-2 and B-21 stealth bombers, the company’s history with undersea warfare goes back nearly 100 years, to include substantial World War II efforts. Years ago, Northrop Grumman was involved in adapting radio frequency (RF) technologies to undersea acoustic systems and developed the first electric torpedoes for Navy submarines.

“We have been working in the undersea domain for well over 50-years, and our support for the Navy stretches back even further,” said Jenny Roberts, director of strategy, investments & integration, Maritime/Land Systems & Sensors division, Northrop Grumman. Roberts, who formerly worked as a director for undersea influence at the Navy’s Undersea Warfare Division, says Northrop Grumman innovators seek to align closely with the sense of mission and purpose now driving the U.S. Navy’s push to stay in front of undersea warfare technology.

“We bring together the power of the corporation’s continuous innovation to provide capabilities our Navy customers need for mission success,” Roberts explained to The National Interest. As part of the ongoing effort to synchronize efforts with the Navy, Northrop Grumman developers are placing a special premium on innovation in the areas of undersea warfare and cross-domain networking.

“To deter future conflict or to ensure we win if future conflict arises, we need to provide capabilities which expand the influence of the undersea force, including connectivity across all domains,” Lytle added. In light of this, Northrop Grumman developers discuss their efforts to link undersea and space domains in the context of the Pentagon’s fast-evolving Joint All Domain Command and Control initiative. JADC2, as it is called, seeks to engender a kind of multi-node connectivity between otherwise disparate pools of information across multiple domains.

For instance, perhaps a surface drone, submarine, ship or fighter jet can identify and share time-sensitive targeting data across domains in near real time, integrating crucial threat information exponentially faster than ever before. The ultimate goal of this is to massively truncate sensor-to-shooter timelines. Perhaps an undersea drone could identify an enemy subsea target, pass the data back to an undersea-warfare commander who in turn instantly sends coordinates to a helicopter armed with Very Light Weight Torpedoes. This innovative kill-chain concept was demonstrated by Northrop Grumman in a Navy exercise

As Navy innovators work intensely to pioneer new methods of undersea communication, many might wish to reflect upon the decades of technical challenges associated with bringing any kind of undersea real-time connectivity to submarine operations. Historically, certain kinds of low-frequency radio have enabled limited degrees of slow, more general kinds of communication, yet by and large submarines have had to surface to at least periscope depth to achieve any kind of substantial connectivity.

The advent of new kinds of transport layer communications, coupled with emerging technologies woven into unmanned systems, are beginning to introduce potential new avenues of data processing and transmission intended to bring greater degrees of real-time undersea data transmission to fruition.

Sea water diminishes the power of electrical transmission, challenges identified many years ago by the Navy and some of its partners who have been working on under communication for decades such as Northrop Grumman. Northrop’s efforts date back to the World War II era and, along with the Navy and other industry contributors, helped pioneer the innovations that helped adapt RF communications architecture to sonar today. Considering this history, there are some interesting synergies woven through various elements of undersea warfare radio communications.

A 2014 essay by Carlos Altgelt, titled “The World’s Largest “Radio” Station,” details some of the historic elements of how the U.S. Navy pursued Extremely Low Frequency (ELF) undersea connectivity. Through its discussion of low-frequency ELF connectivity, the essay explains the technical challenges associated with undersea communication, which seem to dovetail with Lytle’s explanation that undersea communications will need to largely evolve in the areas of acoustics and optics.

As Altgelt notes: “As a result of the high electrical conductivity of sea water, signals are attenuated rapidly as they propagate downward through it. In effect, sea water ‘hides’ the submarine from detection while simultaneously preventing it from communicating with the outside world through conventional high-frequency radio transmissions. In order to receive these, a submarine must travel at slow speed and be near the surface, unfortunately, both of these situations make a submarine more susceptible to enemy detection.”

Lytle’s reference to undersea communications and the ability to “see” underwater is significant with regard to a number of cutting-edge innovations such as Northrop Grumman’s µSAS synthetic aperture sonar combined with advanced machine-learning algorithms, to automatically detect threats on the bottom.

Some of the technical challenges and communications form part of the inspirational basis for newer kinds of undersea drones engineered with advanced levels of autonomy, such that they can find, track, detect and even detonate or explode enemy targets, such as sea-mines, without needing human intervention.

As part of this manned-unmanned teaming equation, the Navy seeks to further harness its growing fleet of air, surface and undersea drones, according to Chief of Naval Operations Adm. Michael Gilday’s CNO NAVPLAN 2021.

“They (unmanned systems) will expand our intelligence, surveillance, and reconnaissance advantage, add depth to our missile magazines, and provide additional means to keep our distributed force provisioned,” Gilday writes.

Gilday’s text brings a few things to mind, as he mentioned drones in the specific context of ISR, something which of course pertains to undersea connectivity and reconnaissance missions. His reference to a “distributed” force also seems quite deliberate, as longer range, higher-fidelity, secure undersea connectivity is crucial to the Navy’s Distributed Maritime Operations strategy, which envisions a disaggregated, yet networked force intended to leverage newer, longer-range kinds of surveillance technologies. This is precisely the kind of tactical circumstance in which unmanned undersea drones can play an integral part, especially when empowered with higher-speed, GPS-like undersea connectivity.

Lytle, a former submarine officer, addresses this circumstance, explaining that UUV undersea functionality is dependent upon limited battery power and would therefore be further enabled by an ability to, as he describes it, “process the data at the source of the sensor” to distinguish and transmit only the most critical information needed by human decision-makers.

“That’s the concept, how do you get all of that information back to a human to analyze. Maybe you don’t want to do that? Maybe you want to allow the UUV to do some initial analysis and make some modifications to its behavior autonomously?” Lytle suggests.

Organizing and optimizing information at the source, Lytle says, requires less power and makes real-time undersea transmission more effective, something which might remove the need to have a forward-operating undersea drone gather data, which can only then be analyzed upon return to the host platform to be downloaded.

“You significantly improve the mission effectiveness of the UUV if you can process data at the source of the sensor, the power and bandwidth required to send back key critical information is significantly lower,” Lytle explained.

This is where AI comes in, as Northrop Grumman developers are working to develop and refine advanced algorithms able to take in “gathered” information, perform analytics and make determinations regarding moments of relevance or significance to commanders. Lytle’s point about forward-operating sensing and computing applies here, as AI-enabled computer systems could take in acoustic or optical sensor data, bounce it instantly against a vast database to make identifications, draw comparisons and perform analysis at the point of collection so as to streamline data transmission and selectively feed the information most crucial to human decision-makers.

Northrop Grumman’s sensing and AI-related computing efforts in this capacity seem to align with Gilday’s NAVPLAN, given that his text makes reference to ongoing work to deploy resilient systems able to “operate with infrequent human interaction.”

“Through analysis, simulations, prototyping, and demonstrations, we will systematically field and operate systems that possess the endurance and resilience to operate with infrequent human interaction,” Gilday writes.

Newer, more advanced computer algorithms allow submarine commanders to operate sensors with much greater degrees of resolution and return-signal image fidelity. Sensors enabled by newer computer applications can see farther and much more clearly underwater.

“With our latest systems, you can get down to less than one-inch resolution. It is the difference between being able to discern a World War II aircraft that crashed into the sea bed, or see much more precisely such that submarine personnel could view bullet holes in the fuselage that must have caused it to be shot down,” Lytle said.

From a tactical circumstance, given that attack submarines and nuclear-armed ballistic missile submarines are likely to conduct large amounts of clandestine patrols, it seems as though an ability to avoid having to surface would bring an extraordinary operational advantage. This is particularly critical given that nuclear-armed submarines certainly can’t risk giving up their position. Additionally, attack submarines are increasingly being developed for undersea ISR missions as they can more effectively access areas along enemy coastlines, where more detectable surface ships might be less effective. As part of this operational equation, Virginia-class attack submarines continue to receive cutting edge upgrades adding new quieting technologies making them much harder to detect.

“A large part of success in the undersea theater is the deterrence value. There is a tremendous conventional deterrence value, because an enemy does not know where the submarine is or know where the unmanned underwater system is... and if you don’t know exactly where it is, you have to search this massive swath of ocean. What we are trying to enable is an operational circumstance wherein the boat never has to come to periscope depth,” Lytle says.

-- Kris Osborn is the Managing Editor of Warrior Maven and The Defense Editor of The National Interest --

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.