The Future of Naval Warfare Will Have a Lot More Spy Submarines

As the threat of advanced air and coastal defense networks increases, especially with regards to the rapid spread of long-range and fast-flying surface-to-air and anti-ship cruise missiles, the innate intelligence collecting qualities of submarines are likely to become even more important. At least one defense company seems poised to capitalize on this potential trend.

German firm PLATH, which builds radio direction finding gear and communications intelligence (COMINT) and signals intelligence (SIGINT) equipment, has been steadily working to expand its product line to include systems intended for subs. In an interview with Shephard Media in May 2017, Torsten Düsing, who acts as both the company’s technical marketing manager and business case manager for naval solutions, specifically highlighted the spying potential of underwater vessels.

PLATH’s particular system, which it unveiled in November 2016, “provides tactically relevant information with minimal mast exposure, listening for communications signals from [anti-submarine warfare] aircraft” when the boat is in danger, Düsing explained. “When not under ASW threat, the task involves building operational intelligence and fundamental knowledge by collecting, recording and direction finding signals.”

Effectively the equipment performs an important defensive electronic counter-measures function, helping crew hide the submarine from enemy forces, as well as acting as a general intelligence gathering tool. PLATH’s complete system includes software package to analyze the signals the sensors receive. It can use the information to map out “emitters” such as radio transmitters, radars, or other electronic systems to give the sailors a better understanding of their surroundings and potential threats. Garnering this electronic order of battle on the fly could also be valuable for building a broad picture of an enemy coastline in preparation for larger operations or for gathering strategic intelligence, such as flight data telemetry from missile tests.

The sail of the USS Annapolis pokes through the ice during an exercise in 2009. One of the masts may have the Radiant Gemstone antenna., USN

“The geographic focus is on urbanized littorals in crisis regions, harbors, shipping routes and military test, training and maneuver areas,” Düsing noted. “The need to establish a line of sight to adversary tactical [very high frequency] sources between 30 and 88 MHz and at the lower end of the [ultra high frequency] band means that only submarines can get close enough.”

Of course, depending on the relative strength of the equipment, this need for a “line of sight” to the target could be a serious issue, even for a submarine. In addition, while PLATH’s system can start to work below the surface, but only actually begins to scan and collect information when the boat reaches periscope depth and raises its appropriate antennas, according to Shephard. The system’s relatively small size – at least according to the German defense contractor – and ability to use existing antennas already on a sub might make up for these limitations. Combining the gear with underwater drones or sub-launched unmanned aerial vehicles, either as antennas, signal relays, or both, could help extend its overall range.

Regardless, Düsing isn’t wrong about navies recognizing the value of having such equipment on submarines, as well as their inherent abilities to sneak in and out of sensitive areas without detection. The basic idea of a radio direction finding and SIGINT kit for sub-surface vessels is probably old news to many larger naval forces around the world. The United States in particular is a pretty prolific operator of spy subs, even if it hasn’t officially acknowledged it as of yet.

USS Jimmy Carter., USN

As of 2017, the U.S. Navy had at least one dedicated spy submarine, the USS Jimmy Carter, also known as SSN-23. The third and last Seawolf-class nuclear attack submarine, SSN-23 has a unique 100-foot-long, 2,500-ton “Multi-Mission Platform” addition to its hull, as well as small, auxiliary devices for precision maneuvering.  The boat is so secretive that an annual history of the ship’s goings on during 2013, which the author obtained via the Freedom of Information Act, only described its main activity as “Mission 7.” But this duty was important enough to earn the sub a Presidential Unit Citation, which rewards “extraordinary heroism in action against an armed enemy.”

Though the service is especially tight-lipped about Jimmy Carter and what she does when she goes out to sea, it has publicly acknowledged that this section can house underwater drones, SEAL special operations divers, and more. It is widely believed this section contained equipment necessary to tap undersea communications cables, a mission that other spy subs, such as the USS Parche, reportedly performed during the Cold War.

An official schematic of the unique modifications to USS Jimmy Carter., USN

But the Navy has also given other submarines SIGINT gear that seems much more in line with what PLATH is now offering. In 2015, Phase Zero, a now defunct section of Gawker Media, published a detailed breakdown of how the National Security Agency (NSA) employed Los Angeles-class nuclear attack submarines to scoop up cell phone signals and other communications chatter, based on documents obtained via former intelligence contractor Edward Snowden. Like the equipment Düsing described to Shephard Media, these modified boats could use their new gear to both track signals for intelligence purposes or spot incoming threats, according to a separate briefing that Phase Zero located from Pennsylvania State University Applied Research Laboratory.

After receiving the data via satellite, NSA would run it all through a software fusion program codenamed BLINDDATE. As of 2008, at least two Los Angeles boats, the USS Annapolis and USS Montpelier, had the requisite antennas and collection gear, which the Navy nicknamed Radiant Gemstone. A cursory Google Search turns up Navy budget requests for additional Radiant Gemstone equipment in 2009 and 2010, as well as information on an associated naval data link and fusion system called Radiant Mercury (RADMERC).

“The RADMERC program facilitates sharing of critical information across security domains and among allied, coalition and inter-agency partners,” according to an official list of the Navy’s Space and Naval Warfare Systems Command’s (SPAWAR) programs. “The Radiant Mercury product provides cross-domain information sharing capabilities from Top Secret/Sensitive Compartmented Information (TS/SCI) to General Service (GENSER) and GENSER to Unclassified.”

Penn State University via Phase Zero

The Russians have had a number of spy submarines similar to the Jimmy Carter, including the shadowy Project 10831 Losharik, but there is little publicly available information on their exact designs and capabilities. Given Russia’s fondness for electronic warfare, it seems likely that the Kremlin’s more conventional submarines have at least some system that can perform basic electronic intelligence functions. As of May 2017, Moscow had reportedly ordered work on a new, massive “research” submarine. If PLATH’s system is as small and easy to install as they claim, it’s entirely possible that other navies with advanced submarine forces, such as China, Israel, Japan, South Korea, Sweden, and the United Kingdom, already have similar equipment. 

However, the company’s add-on kit, or something close to it, would be ideal for smaller navies on tighter budgets. It could readily turn even older or compact submarines into covert spies, giving them renewed life and making them able to spy on ports or other coastal points of interest that might be otherwise off limits to those countries. Beyond submarines of some description, the only other way to get a line-of-sight SIGINT setup into these sensitive regions without immediate detection would be with an advanced, high-flying or stealthy spy plane or drone. Few countries have the resources to operate those kind of systems.  

The Russian Oscar-class submarine Orel., Andrei Luzik via Wikimedia

Of course, if submarine spies become any more common, it’s equally likely that military forces around the world will simply respond by developing even more new and improved anti-submarine defenses. China is already reportedly building an underwater sensor network that might be able to detect underwater craft trying move discreetly through the contested South China Sea and East Seas. In turn, navies are working on quieter and otherwise stealthier submarines. It’s a long-standing game of undersea cat-and-mouse.

What seems clear, both from PLATH’s new developments and existing systems, is that the submarine as an intelligence tool is an idea that can only gain more traction as time goes on, even with smaller navies.

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