There are a range of growing, asymmetric threats facing the missile defense community, but one stands out in particular amid an evolving face of warfare: the proliferation of small unmanned aerial systems. The rise of the commercial drone industry in turn has given rise to a new kind of threat, one that's raising concerns in the defense community with the ease of purchase, relatively cheap cost of entry and low barrier for engagement.

Defense insiders now warn of the dangers these small and inexpensive systems can pose to soldiers and installations, serving as cheap surveillance tools for non-traditional enemies such as terrorist groups or militias. Another serious concern: flying improvised explosive devices.

"Hobbyist drones – particularly those assembled by the operator, and thus not subject to manufacturer-installed geofencing – could be weaponized and autonomously deployed in a terrorist attack against civilians or in an IED-like capacity against patrolling military personnel," a June 2015 paper published by the Center for a New American Security assessed. Adversaries are now employing complex, integrated attacks.

Rick DeFatta, director of the Army Space and Missile Defense Command/ Army Forces Strategic Command Future Warfare Center, described the shift as an "emerging threat trend combining UASs, cruise missiles, ballistic missiles and fixed and rotary wing aircraft in a well-coordinated and synchronized attack process including off-access approaches to cruise missiles and lethal UASs to neutralize our offensive capability and bring effects on critical assets."

"Threats now include rapid advancements in low-cost, enemy air and missile technologies, proliferation of unmanned aircraft systems – especially the low, slow and small category, which pose a significant problem in detection, identification and defeat," DeFatta said.

The Army’s Acting Assistant Secretary for Acquisition, Logistics and Technology Katrina McFarland noted that the changes in threats comes both from "speed and, oddly enough, from the other side of the coin, the low and slow when it comes to UASs." McFarland emphasized that UAS’ speed and autonomy are becoming a prolific global trend. Part of the challenge for the military is that at commercial trade shows, "almost every booth shows some element of autonomy, unmanned, something that’s new, something that’s orchestrated towards a specific vulnerability."

According to one Army spokesperson, unmanned systems has grown from roughly 20 system types and 800 aircraft in 1999 to over 200 system types and approximately 10,000 UAS in 2010. To that end, the Army in July issued a new publication called "Techniques for Combined Arms for Air Defense" with a section dedicated to addressing the threat from small UASs.

UASs "have become more readily available and unmanned technology has become less expensive to buyers from nations who wish to use them to gain an advantage over conventional military forces or employed as a threat," the document noted. "This increased availability can make it difficult for friendly forces to distinguish between friendly and enemy UAS platforms."

Of particular concern are micro/mini tactical and small tactical UASs "due to their minimal or no radar cross section allowing them to come in extremely close proximity to friendly forces undetected," the document read. "These groups are generally tactical assets employed by maneuver units engaging in direct contact operations. They can fly extremely low underneath traditional radar detection zones. They fly very slow and can even hover in place preventing any Doppler-based sensor from detecting them. They are generally very small, making them hard to hit with direct fire weapons."


Swarming capabilities from terrorist organizations likely is a ways off given the amount of resources necessary for successful operations, said Chris Harmer, senior nonresident naval analyst at the Institute for the Study of War.

Swarming requires a robust infrastructure of UAS devices, personnel, logistics and ground control systems, as well as the risk that many of these devices could be lost. Many of these groups have pressing intelligence, surveillance and reconnaissance needs, Harmer said, and they do not want to lose the devices they have to support a large-scale operation such as swarming a particular target. Harmer believes the biggest near-term threat is the continued weaponization of these commercial devices turned into flying IEDs, while a greater concern down the road would be a more autonomous capability.

Currently, the devices used by these organizations require a great deal of ground control. While being sure not to downplay the threat these small devices pose, Harmer said many of these terrorist groups understand that the U.S. has far superior electronic capabilities and can easily detect and intercept UAS signals, discouraging direct attack on U.S. installations. Rather, the most likely use of UASs against the U.S. by terrorist organizations would be ISR used to target data for larger surface-to-surface weaponry.

A spokesman for the Joint Improvised-Threat Defeat Organization, or JIDO, outlined four primary ways ISIS uses UAS, reported Defense News, C4ISRNET’s sister publication. Among them: tactical observations that include use of full motion video to look for attack opportunities, learning how Iraqi security forces respond to attacks through aerial observation to adapt, vector suicide vehicle-borne IEDs and finally to generate propaganda. The spokesperson did note that it is more common for small, inexpensive commercial UASs to be used for spying on opposing forces.

Thomas Joscelyn, senior fellow at the Foundation for Defense of Democracies, also described how terrorist organizations within the last year or so increasingly used UASs to film battles, using the footage for propaganda. Joscelyn told C4ISRNET that zooming in on fighters and filming battle sequences is an effective and dramatic method of depicting their operations in order to sell their story for recruitment and propaganda purposes.

The drone worries have spurred the Pentagon to ask for more money to fight the UAS threat in Iraq, where troops are deployed supporting counter-ISIS operations. DoD requested $20 million in additional funds to address the growing UAS threat posed by ISIS, which includes the delivery of small, precision IEDs. According to Defense News, more funds are needed to purchase solutions for detecting and defeating UASs – in addition to $189.7 million dedicated to counterterrorism in the fiscal 2015 overseas contingency operations budget.

Use of these commercial systems is not just reserved for terrorist organizations. Tactical UASs have been widely observed in the Ukrainian conflict involving Russian-sponsored Ukrainian separatists in Eastern Ukraine.

"Russian UAVs are able to fly overhead and spy on formations – things that we haven’t had to worry about for the past 15 years. And then they’ve got precision fires that are connected to their UAVs," Lt. Gen. Ben Hodges, commanding general of Army Europe, said in August following a recent visit to Ukraine.

Harmer said while Russia lags about 10-15 years behind the U.S. in terms of UAS technology, lacking any weaponized platforms or high-altitude, long-endurance systems, the small devices they do operate and export to Ukrainian separatists suffice.

In the Cold War, Harmer said, the Russians knew the U.S. had better equipment, but their equipment was good enough for what they’re doing. For the wars Russia is engaged in currently, these systems are good enough. In Syria, they can fill the gaps for persistent ISR when manned aircraft are grounded, he said. The small size and slow-moving nature of these systems pose significant challenges in tracking them.

In the domestic sense, consider how a gyrocopter literally flew under the radar to land on the grounds of the United States capital last year. Many of these systems register as birds or other objects on radar.

"The counter-UAS area poses a very difficult challenge. [One] problem that we have here is not just the sheer number, but there’s also challenges trying to identify friend from foe, how and what in terms of engagements [and] how we protect our assets that we have – bases, stations, ranges," McFarland said. "From both the casual and the not-so-casual maneuvering of these assets, we’re seeing broader and broader use of them. Most of our sensors have difficulties…in finding and seeing the smaller and more slow-moving or different signatures than we’re used to, and we have to upgrade our sensors or change our use of the sensors to be able to track and then classify some of those threats."

Many organizations within the military are turning to industry for help with counter-UAS solutions to protect troops and assets. The Air Force earlier this year put out a notice requesting portable and lightweight counter-UAS devices. The notice requests systems capable of defeating threats by passively detecting radio frequency signatures of UASs or command and control ground stations – and to do so while maintaining portability and weighing less than six pounds.

The Defense Advanced Research Projects Agency also put out a request for information as recently as August that could "support the development of new DARPA programs that could enable a revolutionary layered defense approach to achieving mobile force protection, including counter-unmanned air systems (CUAS) capabilities," the agency said. "The solution should be scalable and modular such that it could be deployed in multiple defense applications on a variety of platforms (vehicles and vessels); the solution is intended for the defense of fixed and mobile ground and naval forces."


Officials are quick to reassure that measures are being taken to thwart this challenge.

"The good news is there’s a lot of [science and technology] work going on in [the counter UAS] area across the services, and we’re heavily engaged in joint work with them," McFarland said. She also offered that the Army has been identified to develop a joint capabilities document for Tier 1 and Tier 2 UASs and their counter-UAS missions. These are tactical systems ranging in size from zero to 55 pounds that operate at altitudes under 3,500 feet – exemplified by Aerovironment’s RQ-11 Raven and Insitu’s ScanEagle.

McFarland also noted that the Army is readying a first capability set to "allow us to learn and grow from the activity of how to manage Tier 1and Tier 2 UASs." From operational and tactical standpoints, officials talk about countermeasures in two categories: kinetic and non-kinetic.

"The question is, how do we put a suite of defenses in place in layers that allow us to defeat the high end and the low end?" Maj. Gen. Neil Thurgood, deputy for acquisition and systems management within the office of the Army’s Assistant Secretary for Acquisition, Logistics and Technology. Thurgood was referring to defense against small UASs and larger, more sophisticated systems.

"Clearly you don’t want to shoot a Patriot [missile] at a $3,000, 50-pound UAS, and you’re not going to kill one up at 10,000 feet with a Stinger," he said. "So the department, actually, has a plan that is both kinetic and non-kinetic – means to either kill it or cause it to interrupt its mission set, or you kill its sensor or payload."

Kinetic measures include a projectile that will shoot an incoming object out of the sky, while non-kinetic means are more complicated and numerous. These might include jamming the aircraft’s signal, interrupting the link between the operator and the device, commandeering the vehicles or telling them to turn around.

"So if I see a little UAS with a radar, how do I kill that thing? Do I kill it electronically, do I make it land, do I make it break track and go home or do I kill it?" Thurgood said. He added that the countermeasure used to defeat a UAS is connected to the method used to track it.

"The hardest problem you have with any of those [is] do I see it because I see the skin of it, or do I see it because I tracked a radio signal of it?" Thurgood said. "Depending on how you see it may depend on how you kill it. So I can track a radio signal way out there and I can interrupt it way out there so I don’t necessarily have to physically see it. In some cases, I need to see it because they masked the radio signal and I have to kill it because I see the skin of it or see the heat signature of it or some other methodology."

One solution is repurposing existing systems for counter-UAS missions. Last year, the Army conducted tests using a modified Counter-Rocket, Artillery, Mortar, or RAM, system for counter-UAS. The tests consisted of tracking small aircraft, in this case class 2 UAS, and shooting it down with command guidance and command warhead detonation.

Northrop Grumman has also demonstrated existing systems repurposed to track UAS. Last year in conjunction with the Army at Fort Sill, Oklahoma, the company tested its Venom counter-UAS system, a ground-based targeting system. Venom only tracked UASs during the demonstrations – it did not conduct countermeasures or provide precision targeting coordinates during the testing. As a vehicle agnostic tool, Northrop said it can be integrated on a range of platforms.

The Army recently issued an announcement to test the waters for potential contractor solutions to allow the existing AN/TPQ-53 radar – which detects, classifies, tracks and locates projectiles fired from mortar, artillery and rocket systems – to detect, track and identify UAS threats.

Thurgood reiterated that future counter-UAS concepts and solutions will likely be a combination of new systems and repurposed suites. But for the time being, the military’s existing systems will remain on the battlefield until future iterations emerge.

"Right now most of the systems that are out there, electronic or kinetic, are standalone systems. We’ve got a lot of radars on the battlespace; eventually we’ve got to hook those things together. That’s what you want," he said. "The long-term outcome is you want an integrated system that you can identify [the UAS] and then decide what you want to do with it. That technology doesn’t exist yet…so right now we have some federated systems and we’re going to field those because you don’t want to soldiers to be unprotected. We’ll field those until we can get into an integrated suite."

Mark Pomerleau is a reporter for C4ISRNET, covering information warfare and cyberspace.

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