The Drone Menace
Not so long ago, it would be inconceivable to imagine unmanned airborne systems (UASs) as a viable threat. Fast forward to 2020 and you could own a Tello quadcopter drone with a high definition camera for just over $100. At the time of the writing, the maker of the Tello is Da Jiang Innovations Science and Technology Company (DJI), a Chinese company based in Shenzhen. DJI enjoys a market monopoly with nearly 80 percent of drones operating in the U.S. and Canada and 74 percent flown globally are manufactured by DJI. DJI offers models cover the full spectrum from the cheaper Tello to the high-end Phantom and Inspire variants. DJI also offers numerous mountable optic packages to include infrared cameras for their drone line up. In addition, DJI offers low noise, high performance propellers to enhance flight behavior and minimizing noise output—thereby decreasing audible detection.
DJI enjoys its market domination but is also making other more disturbing headlines. China does business much differently than the United States; for example, China requires major companies (including DJI) to maintain close ties to the government. This raises serious privacy concerns. The U.S. Army halted use of DJI drones in 2017, claiming that DJI shared sensitive U.S. infrastructure information from its drones with the Chinese government. It is known that Chinese drones were used to monitor water reserves, power plants, rail hubs, and other large-scale infrastructure.
This is of particular concern because application software can be readily downloaded to a user’s iPhone or iPad to turn the device into a drone controller unit. DJI claims that it gives users complete control to choose what data to upload or not, including flight plans, videos, and images. However, the software has an automatic function to store user flight logs and it encourages uploads of data. In DJI’s defense, they do offer drones that do not transmit data over the internet and they claim that users can adjust the setting and control how their data is stored and transmitted. Though there is a lack of definitive proof of data transfer and exploitation from DJI drones by China, it is hard to believe this avenue has not been used to gain some advantage or (at a minimum) collect on U.S. infrastructure assets.
Unfortunately, civilian drones can easily be modified to carry out attacks by attaching weapons and explosives. During the Battle of Mosul, ISIS conducted over 300 drone operations and of those, roughly 100 were armed strike missions. A more daunting concern: If simple explosives already being used on drones, what prevents a terrorist organization with intent to cause disarray from upping the ante to chemical, biological, or radioactive payloads? Now-deceased terrorist Abu Musab al-Zarqawi expressed interest in acquiring small-scale chemical weapons and mentioned deployment of these weapons would be very easy with access to a drone.
There is Hope
UAS includes the airborne vehicle, ground controller or station, and associated data links, as well as other equipment used to support the whole system. In contrast, Unmanned Aerial Vehicle (UAV) usually pertains to the flying component (drone) only. UASs have become popular not only in the industrial section but also with civilian enthusiasts. Sometimes these UAS operators “accidentally” fly their drones too close to Department of Defense assets, including bases, ships, and government buildings. Surveillance and weaponized drones are of particular concern and pose the biggest threat to determine pattern of life or to carry out a physical attack.
When weapon systems advance, so too do countermeasures. For example, the FIM-92A—more commonly known as the basic STINGER (man-portable surface to air missile)—uses an infrared seeker to guide the payload to its target. The counter to this was the development of flares, which can be deployed in the event of a STINGER launch; these flares burn very hot and confuse the missile, leading it away from its intended target. Another example is the Decoy Launching System (DLS) Mk-53 (NULKA). NULKA works against radar homing missiles by broadcasting a much larger radar signature than the target, which fools the missile and lures it away. Similarly, there are counter UAS (c-UAS) systems capable of detecting, engaging, and defeating drones that get “too close.” The c-UAS business has grown over the past few years, with well over 100 manufacturers advertising a myriad of different products. Thus, there is hope that c-UAS devices exist that can be employed to neutralize a rogue drone.
The c-UAS process can be broken down into three distinct pieces: platform type, detection and tracking systems used, and interdiction method. Platform type is categorized into three categories: ground based (stationary or mobile), hand-held devices, UAV-based (countermeasure is mounted on another UAV). The tracking and detection systems compose five different means: radar, Radio frequency (RF), Electro-optical (EO), infrared (IR), and acoustic. There can also be a combination of tracking and detection systems used to detect the UAS. Kinetic and non-kinetic methods are employed for interdiction; kinetic methods include nets, projectile, and even lasers. Non-kinetic approaches focus primarily on jamming, which entail jamming the RF signal between the drone and its operator or jamming its GPS link. Use of either of these methods should initiate a “return to home” maneuver or cause the drone to hover and/or descend to the ground. Another non-kinetic approach is spoofing, which occurs when another user takes over the drone by hijacking the communication link. The employment of these systems or a combination of them can be effective at keeping prying eyes away from DoD assets and critical U.S infrastructure.
The Swarm Awakens
With all the c-UAS products out there, mitigating the drone threat should be relatively easy. However, the new Sith on the block is the drone swarm. Imagine multiple incoming targets with different directions, altitudes, and intentions or just one large formation coming in low, fast, and locked on target. The 2019 Gerard Butler film Angel has Fallen depicts a Hollywood inspired drone swarm attack scene that soon may prove to become reality. The scene depicts multiple swarms using machine learning facial recognition techniques to identifying and eliminate pre-selected targets. Although not perfected yet, UAS employment on the battlefield is heading in this direction. Swarms could provide a wide array of low-cost battlefield application—from overwhelming the common operational picture with targets to intelligence, surveillance, and reconnaissance over large, contested battlespace.
One of the greatest advantages of swarm technology is the lack of a human controller for each unit in the swarm. Although not viable yet, technology is advancing down this path. The methodology to develop drone swarms can be traced to animal and insect behaviors. Think of a murmuration of starlings or schooling fish and how they all seem to move and react as one. However, each bird or fish has its own brain and neural network allowing it to make independent decision from the group. Bees and termites represent another great example. The queens do not pass instructions to each individual member; instead, the bees and termites do their own thing with assistance from chemicals signaling intent to accomplishing the same goal [preservation of the queen/colony].
If swarm technology can successfully be coupled with machine learning and incorporate precise tactical munitions, we may have a situation on our hands similar the scene in Angel has Fallen. Paul Scharre from the Center for a New American Security think tank hits the head of nail stating, “Swarming allows you to build large numbers of [relatively] low-cost expendable agents that can be used to overwhelm an adversary. This reverses the long trend of rising aircraft costs and reducing quantities.” He also tactfully adds that, “unlike having a large number of soldiers, robotic agents can coordinate on a scale that would be impossible for humans.”
The Rise of Layered Defense
Drones are small, portable, and relatively cheap. They are easy to modify, fitting them with explosives or equipping them with jammers to disrupt U.S. and allied communication circuits. There exist numerous c-UAS devices with kinetic and non-kinetic abilities to neutralize a drone. The big question is what system is needed to counter this threat. One c-UAS to defeat a swarm of drones will more likely than not fail for several reasons.
First, a swarm of drones or multiple UASs coming from different directions may very well overwhelm the system, allowing some to get through to the target. Another example is a UAS with a preprogrammed flight path. This allows for the UAS to operate autonomously from the controller, meaning there is no RF exchange between the UAS and the operator. If a RF jammer is used against a UAS configured to fly using GPS waypoints, there is no RF signal and the c-UAS RF jammer will fail to neutralize the threat. Another problem of RF jamming is collateral damage: the jammer may disrupt other unintended military technology, such as radio communication pathways.
The U.S. military needs to prepare a layered defense in-depth network to engage drone swarms. UASs need to be identified at distance to give enough time to initiate the proper response14. Both detection and interdiction must take a layered, in-depth approach. All pathways to the target must be covered down with c-UAS devices; total coverage is defined as 360 degrees in azimuth and from below the horizon to straight up in the sky. Radar combined with RF, EO, and IR should be used in a parallel approach to identify and track UASs. Once the UAS or swarm is determined to have hostile intentions, a layered defense in-depth network for using non-kinetic and kinetic fires must be engaged early to ensure enough time to eliminate the threat. The situation and reaction time remaining will ultimately determine the course of action taken.
In a perfect scenario, the UAS or swarm will be detected at range and determined to be a threat with enough time to employ non-kinetic means to neutralize the threat. Unfortunately, this is unlikely. The U.S. armed services can expect multiple UASs and or swarms of UASs intent on causing harm—all coming in at once and from different directions and altitudes. Some may be operator controlled, some may have GPS preprogrammed flight paths, and some in the future may have machine learning and decision making capabilities in the individual units. Layered defense in depth is the answer.
Ground based systems such as Raytheon’s “Phaser” and multi-spectral Targeting System (MTS) provides advanced UAS defense using wider beam microwave technology and a finer beam focused laser respectively. These and similar ground-based systems must be the backbone of the layered defense in depth scheme and must be coupled with hand-held and UAV-based systems. All three platforms need to be able to field non-kinetic and kinetic options to ensure full aerial coverage over the battlefield. Steven Bucci, former U.S. Deputy Assistant Secretary of Defense for Homeland Defense and Defense Support to Civil Authorities states that layered missile defense is key to killing drone swarms: “We must continue to develop technologies that will detect these types [UAS and swarms] of small, unmanned aircraft and find ways to more effectively protect our assets from these asymmetrical assaults.” Every Marine is a rifleman, every sailor is a firefighter, and soon every Airman, Marine, sailor, and soldier will be hand-held c-UAS operator once the UAV/UAS threat is upon us.
