Check Out This Backpack-Mounted Signals Intelligence System Worn By A Marine Special Operator

“Body-worn” signal snooping gear gives American special operators an additional way to spot and track enemy forces, and monitor their surroundings.

byJoseph Trevithick|
Land-Based Electronic Warfare photo


A recently released picture of Marine Raiders conducting realistic urban training shows an operator wearing a backpack with a large tubular antenna sticking out it. While this system, and the entire picture, looks like it could be ripped straight from a blockbuster action movie or modern military first-person shooter video game, it is a very real tool that is able to detect and geolocate enemy signals. This can provide useful real-time intelligence about enemy forces and their movements, as well as improved general situational awareness.

The Raiders in question were training in Nashville, Tennessee, together with regular Marines, earlier this month, as part of what is known as a Raven exercise. Marine Forces Special Operations Command (MARSOC) uses Raven exercises to prepare Raiders for upcoming deployments. In one picture, seen at the top of this story, the Raider carrying the system in question, which is part of a larger family known as the Joint Threat Warning System (JTWS), is crouching in front of a Western Star truck in a warehouse, while another provides immediate security. In another shot, seen below, what may be the same JTWS-equipped Raider is seen together with other Marines outside what could be the same building.

Marine Raiders, as well as conventional Marine infantrymen, take part in a Raven exercise in Nashville, Tennessee in May 2021. A Raider on the right is seen carrying a man-portable Joint Threat Warning System (JTWS), as evidenced by the large tubular antenna protruding from his backpack., USMC

These pictures, and others from this same Raven exercise, describe what is happening as a mock "night raid" and that the exercise, as a whole, "simulates real-life tactical scenarios to enhance overall unit interoperability, effectiveness and lethality against an adversarial force."

Integrating the backpack-mounted component of the JTWS family into this exercise would have have given the combined force of Raiders and conventional Marines an important additional source of information during the drill, just as it would in real life. The exact capabilities of this particular system, which appears to be the most recent iteration of the "body-worn" segment of the larger JTWS family, are unclear. 

Marine Raiders use a Humvee to provide security during the mock night raid conducted as part of the recent Raven exercise in Nashville. What appears to be the antenna associated with a JTWS, possibly just another appearance of the backpack-mounted system, is seen on top of the vehicle., USMC

A 2019 briefing from U.S. Special Operations Command's (SOCOM) JTWS Program Manager said that this system was capable of providing very-high-frequency/ultra-high-frequency (VHF/UHF) direction-finding capability. Other sources make clear that even the backpack elements of the JTWS family have some level of geolocation and communications intercept capabilities. This means that they can both determine the source of a radiofrequency emission and, if it's a certain type of unencrypted radio or other communications chatter, listen in on it.

A briefing slide describing the general capabilities of various components of the JTWS family, including "body-worn" systems., SOCOM

Available information also indicates that location data can be displayed, even for moving targets, overlaid on digital map on a hand-held tablet-like device, along with other relevant information. In the picture at the top of this story, the Raider carrying the system can be seen looking down at this portable user interface. Operators should be able to push this information to other units or larger command centers, as well.

An image showing the kind of information that the operator of a backpack-mounted JTWS can view on their hand-held tablet-like device. , SOCOM

In the past, SOCOM has described the various versions of these backpack-mounted systems as a "Threat Warning, Force Protection, and Situational Awareness toolbox." In short, they offer even small units a way to spot hostile or potentially hostile forces before they necessarily see them, as well as providing a clearer picture of the immediate battlespace, in general, based on the locations of different kinds of radiofrequency emissions. 

In addition, when conducting raids and other direct action missions, as well as long-range "special reconnaissance" operations, it can help pinpoint the positions of targets of interest, as well as collect other potentially actionable signals intelligence (SIGINT) data, in near real-time. It's possible that the system may be able to spot certain kinds of improvised explosive devices that use remote triggers of some kind, such as cell phones, which regularly ping their networks to ensure they remain connected.

A slide from a 2018 briefing that offers other details about the backpack-mounted components of the JTWS family., SOCOM

It is worth pointing out that man-portable radio direction-finding equipment and even more robust signals intelligence systems are hardly new. Various types have been employed by conventional U.S. forces, as well as special operations units, too. The particular system employed in this recent Raven exercise also has a general outward look that is very similar to various backpack-mounted electronic warfare jammers, primarily intended to disrupt improvised explosive devices, that have been in widespread service for years now.

A US Army soldier from a conventional unit carrying a Wolfhound system, another type of backpack-mounted signals intelligence suite., US Army
A US Marine carries a THOR II backpack-mounted electronic warfare jammer designed to counter improvised explosive devices in Afghanistan in 2012., USMC

Different iterations of the various components of the JTWS, alone, which also includes larger systems designed for installation on various kinds of manned and unmanned aircraft, boats, and ground vehicles, have been in service for decades now. In the early 2000s, there existed at least some legacy signals intelligence systems already available to SOCOM, including man-portable types, were also officially made part of the larger JTWS family. 

Other backpack-mounted systems that have been part of SOCOM's JTWS family over the years., SOCOM

"The legacy SOF [special operations forces] SIGINT systems have demonstrated the high value of tactical SIGINT during many recent missions involving SOF," then-Brigadier General Donald Wurster, an Air Force officer serving at that time as the director of SOCOM's Center for Intelligence and Information Operations, told members of the Senate Armed Services Committee all the way back in 2004. "The acquisition and fielding of JTWS is key to providing enhanced situational awareness, force protection and time sensitive intelligence for targeting to supported SOF elements."

However, as one writer for Soldier Systems Daily noted while discussing JTWS developments in 2017, "while I used an early version of this system in Haiti over 20 years ago, it has come a long way from the AN/TRQ-30 DF [direction-finding] loops first fielded to 3rd Group [the U.S. Army's 3rd Special Forces Group] in 1990. They were the height of 1950s technology and the receiver used like 30 D cell batteries."

A drawing showing one type of tripod-mounted loop antenna used with AN/TRQ-30 man-portable direction-finding system. , US Army

Advances in general computing power and the continued miniaturization of electronics mean that signals intelligence suites, as well as related electronic warfare and electronic support measures systems, have been steadily improving in overall capability, while shrinking in size, over the years. This is not to mention more recent developments in fields such as artificial intelligence and machine learning that look set to revolutionize intelligence gathering and electronic warfare, among other aspects of future conflicts, broadly.

Advanced electronic warfare capabilities, many of which are building off of existing signals intelligence systems, in particular, are of growing interest across all of the branches of the U.S. military, including among conventional and special operations units. This comes as adversaries and potential opponents, especially potential near-peer competitors, such as Russia and China, have been making their own significant strides in these fields, which could have serious ramifications for American forces in future combat operations and non-combat activities. This is something The War Zone has explored in depth in the past.

With all this in mind, it seems more than likely that man-portable signals intelligence systems just like the ones that Marines Raiders brought to this recent Raven exercise, as well as similar electronic warfare suites that can fit inside a backpack, will become an increasingly common feature in future U.S. military operations, whether they involve special forces, conventional units, or both. 

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