Drone swarm technology—the ability of drones to autonomously make decisions based on shared information—has the potential to revolutionize the dynamics of conflict. And we’re inching ever closer to seeing this potential unleashed. In fact, swarms will have significant applications to almost every area of national and homeland security. Swarms of drones could search the oceans for adversary submarines. Drones could disperse over large areas to identify and eliminate hostile surface-to-air missiles and other air defenses. Drone swarms could potentially even serve as novel missile defenses, blocking incoming hypersonic missiles. On the homeland security front, security swarms equipped with chemical, biological, radiological, and nuclear (CBRN) detectors, facial recognition, anti-drone weapons, and other capabilities offer defenses against a range of threats.
But while drones swarms represent a major technological advancement, unlocking their full potential will require developing capabilities centered around four key areas: swarm size, customization, diversity, and hardening.
In general, the more drones in a swarm, the more capable the swarm. Larger underwater swarms can cover greater distances in the search for adversary submarines or surface vessels. Larger swarms can better survive some defenses. The loss of a dozen drones would significantly degrade the capabilities of a twenty-drone swarm, but would be insignificant to a thousand-drone swarm.
Media reports indicate that China has successfully tested a swarm of one thousand drones. And China appears to be interested in swarm capability as a method of attacking US aircraft carriers. Although Intel has fielded a swarm of 1,218 drones, this does not appear to be a true drone swarm, relying on programmed behaviors instead of inter-drone communication.
There is little reason to believe swarm size could not continue growing significantly. Building a large swarm primarily requires the ability to handle massive amounts of information. More drones mean more inputs that could affect the swarm’s behavior and decisions. And on a basic level, more drones mean a greater risk of one drone crashing into another.
Of course, the importance of swarm size will depend on the mission. Stealthier missions against softer targets do not require thousands of drones. And large numbers of drones could be detrimental, drawing unnecessary attention from defenders. But massive attacks on adversary bases and other hard targets might need exactly that. An attack on a hardened target means greater expectation of loss and greater need to mass offensive power.
A future drone swarm need not consist of the same type and size of drones, but incorporate both large and small drones equipped with different payloads. Joining a diverse set of drones creates a whole that is more capable than the individual parts. A single drone swarm could even operate across domain, with undersea and surface drones or ground and aerial drones coordinating their actions.
Current drone swarms consist primarily of small, identical, sensor drones, but simple multi-domain swarms have already been developed. One such swarm involves a flying drone collaborating with a walking drone. The aerial drone maps the nearby area and the ground-based drone uses that information to plan its actions. Another experiment demonstrated a swarm of five differently sized ground drones, each equipped with different sensors and different functions. The five drones work together to carry out a basic human rescue mission, transporting a dummy to a different location.
Drones within the swarm may serve different roles based on their different capabilities. Attack drones carry out strikes against targets, while sensor drones collect information about the environment to inform other drones, and communication drones ensure the integrity of inter-swarm communication.
Small sensor drones can provide reconnaissance for larger attack drones, gathering information on adversary targets and relaying it to attack drones to carry out strikes. Even the drones specifically tasked with conducting attacks can be diverse. A drone swarm could incorporate attack drones of different sizes, optimized for different types of targets. A swarm intended to suppress enemy air defenses could include drones equipped with anti-radiation missiles for defeating ground-based defenses, while other drones might be armed with air-to-air missiles for countering adversary aircraft.
Cheap dummy drones might actually prove to be disproportionately valuable contributors to a swarm’s mission, absorbing attacks to protect more sophisticated drones or separating from the main swarm to draw away defenders. But the key here is that diversity enables more complex behaviors.
Customizable drone swarms offer flexibility to commanders, enabling them to add or remove drones as needed. This requires common standards for inter-drone communication, so that new drones can easily be added to the swarm. Similarly, the swarm must be able to adapt to the removal of drone, either intentionally or through hostile action.
Customization also allows commanders to adapt the swarm to the needs of a situation. For missions demanding a smaller profile, a commander may remove drones. A commander may also vary the capabilities of the swarm itself, adding drones equipped with different types of sensors, weapons, or other payloads.
At the extreme end, a customizable drone swarm could break-apart or merge together into a single unit while in the field. This would enable rapid response to changing battlefield dynamics. For example, a small group of undersea drones could break off from the larger mass to investigate a possible adversary vessel. If the new target presents a significant threat, the full swarm may re-form to tackle the challenge.
Research on drone swarm customization shows the concept is possible, but development is still in the early stages. A recent study in the scientific journal Nature demonstrated a basic mergeable robotic nervous system. A handful of very simple robots merge together to form a single, larger robot, or separate into smaller groups.
In the future, providing commanders with a drone swarm could be akin to providing a box of Legos. Commanders may be given a collection of drones that can be combined in different ways as the mission demands. This enables rapid responsiveness to changes in the military environment.
Drone swarming creates significant vulnerabilities to electronic warfare; protecting against this vulnerability is critical. Drone swarm functioning inherently depends on the ability of the drones to communicate with another. If the drones cannot share information due to jamming, the drone swarm cannot function as a coherent whole.
Vulnerabilities to electronic warfare depend on the composition of the drone swarm. Swarms may incorporate drones specifically designed to counter jamming. Communication drones could serve as relays to share information, provide alternate communication channels, or simply detect possible jamming and issue retreat orders. Drone swarms could also incorporate drones equipped with anti-radiation missiles and other anti-jamming weapons.
Advances in technology may also harden the swarm against electronic warfare vulnerabilities. Novel forms of communication may weaken or entirely eliminate those vulnerabilities. For example, drone swarms could communicate on the basis of stigmergy. Stigmergy is an indirect form of communication used by ants and other swarming insects. If an ant identifies a food source, it leaves pheromones for future ants to find. If the next ant also finds food there, it leaves its own pheromones, creating a stronger concentration to draw even more. Applied to a drone swarm, an approach like this that uses environmental cues could mitigate vulnerabilities to jamming.
Developing drone swarm technology is a multi-service, interagency challenge. Drone swarms offer significant capability for the US Navy in searching for submarines or serving as surface weapons platforms. The Navy is already developing a basic autonomous boat swarm capability, and the US Marine Corps has successfully tested small swarms for infantry to carry out strikes and electronic warfare attacks. Drone swarms offer the US Air Force a novel platform for operations to suppress enemy air defenses, and Greg Zacharias, former chief scientist of the Air Force, believes future F-35 pilots will incorporate information collected from drone swarms. Robotic collaboration could improve the Department of Homeland Security’s ability to detect CBRN usages and map disaster impacts.
But for all of these actors and all of these missions, truly unlocking the swarm’s potential will require US military stakeholders to deliberately emphasize improvements in four key areas: size, diversity, customization, and hardening. Failure to do so will mean being on the wrong side of the power of the swarm.
Zachary Kallenborn is the lead author with Philipp Bleek of “Swarming Destruction: Drone Swarms and Chemical, Biological, Radiological, and Nuclear (CBRN) Weapons” forthcoming in The Nonproliferation Review. The article rigorously analyzes these and other applications of drone swarms. Zachary is a freelance researcher at the National Defense University, where he is conducting a study on emerging technology and CBRN terrorism and is also an analyst at the Cadmus Group where he writes, edits, and analyzes FEMA doctrine.
The views expressed are those of the author and do not reflect the official position of the United States Military Academy, Department of the Army, Department of Defense, or any of the author’s current or past employers or funders.
Image credit: DARPA
Great article and agree with the idea that drone swarms provide incredible opportunities if we get there first. Manned/unmanned and “combined arms” drones make great sense for areas of research.
How much work/thought have you put into energy? We aren’t quite there yet, for small drones anyway, on getting any kind of persistence.
LTC Joe Geary
Hi LTC Geary,
Thanks for your kind words and I appreciate the engagement!
As to energy: I definitely think that is a critical issue for both drones generally and swarms specifically. And especially so with smaller drones. No power means the drone is worthless. And perhaps less than worthless as the dead drone may take up space or be exploited by adversary intelligence. I know there is considerable ongoing work on addressing the power issue. One company claims to have brought the flight-time for a simple quadcopter up to 2 hours (https://www.forbes.com/sites/jeremybogaisky/2018/09/10/impossible-aerospace-drone-2-hours/). And another has made significant improvements to battery technology generally (https://www.technologyreview.com/s/610792/this-battery-advance-could-make-electric-vehicles-far-cheaper/).
The energy challenge will also, of course, depend significantly on how and where the swarm is used. Swarm-based missile defenses and other generally defense-oriented applications are likely to be used on or near friendly territory where recharging may be less of an issue. Offensive uses, especially on adversary territory, definitely presently a much greater challenge. That would require some form of portable charging that could also become a vulnerability for the swarm. I'm still thinking about that issue, but it seems to me the logical solution is incorporating charging in some form of larger platform (either existing, such as the F-35 based swarm, or some form of novel drone mothership).
So, overall, I do think it is a challenge but not an insurmountable one.
Zak – solar power, energy scavenging and dynamic soaring, as well as outliers like power beaming may solve the power issue for small UAVs, along with approached like perching to conserve energy. There's a chapter on this in my book Swarm Troopers – let me know if you'd like a copy.
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"Revolutionizing the dynamics of conflict"? At the end of May 1942, an airborne swarm attacked the city of Cologne, delivering almost 1500 tons of explosives over a 90-minute period, starting over 2500 fires and destroying over 16,000 buildings. History knows this as the first of the RAF's thousand plane raids. Swarm tactics are nothing new to warfare, particularly in the era before precision munitions. WWII bomber raids routinely sent hundreds of aircraft against targets. The German submarine force employed "wolfpack" — swarming — tactics against Allied convoys. Japanese kamikaze aircraft swarmed U.S. ships. Combat on the ground involved maneuvering hundreds of men around battlefields. Swarm tactics are nothing new to warfare, particularly in the age before precision munitions.
Nor is platform autonomy as revolutionary as it sounds. Autonomy implies capability to decide whether to attack or not…once committed to an attack, a swarm attack by unmanned platforms is little different than an attack by massed aircraft, submarines, or missiles. Dealing with such attacks means revitalizing 20-30 year-old capabilities and adapting them to advances in platform size, performance, and precision — no small task, but not the mind-bending change the author implies.
Traditional aviation projects take 20-30 years to create a stable outcome, and billions of dollars to fund. Pilots take years to train and replace, and dead flight crews always spell bad news for the government. Traditional SAM and Radar tech is getting better, InfraRed radar and hypersonic missiles represent a threat to that entire investment. What is different here is very low expense, low risk, potential to evade traditional countermeasures and detection, and the ability to create a team of workers, which will autonomously attack in complex ways. The drones could be as small as a fly, dropping a single dose of cyanide in the General's coffee, or mobbing an aircraft on a flight deck with less than a gram of semtex, but in 100 drone vehicles. The Houthis claimed responsibility for a drone attack, on 9/13/2019 – and whilst that is unsubstantiated, even a small militia can plausibly afford to launch drone attacks. Aerial war got ex-human, cheap and inventive, it's very different from the past.
Unfortunately for everyone I have electronic countermeasures. Both already and in the works. This isn't a videogame.
Just tell me one thing. Will they be able to record things encountered and put the Big Foot theory to rest?
Great article. I enjoyed reading it very much.
I'm wondering if you have thought of swarm technology for the future of commercial public drone vehicles. Companies like Uber and Bell are teaming up to launch an air taxi service in America, and there are many European companies further developing drone vehicles. There will be a point one day when it will be common to see many drone vehicles in the air. The increase of flying vehicles would require each drone to communicate with each other to avoid collisions. I see a benefit of swarm technology for this application, what do you think?
Thanks for sharing your thoughts! I had not considered that angle and definitely does raise some interesting issues. Initially, I'm somewhat skeptical about using swarming technology for collision avoidance in that context, because I imagine general machine vision that current autonomous vehicles already use would likely account for collisions. Any human-sized vehicle would necessarily be large with numerous sensors and a vision-based avoidance system would be less vulnerable to disruption (don't want to cause a crash because of a weak signal; military applications seem likely to operate at large distances where communication is as much about coordination as collision avoidance). That said, since we don't know what the future may hold, I can't dismiss the possibility entirely. It is certainly plausible that some future application may require close, enduring collaboration that can't be achieved with machine vision (maybe some sort of multi-vehicle autonomous convoy?).
Your point also raises an interesting theoretical question: how frequently do drones need to communicate to constitute a swarm? Not sure what the answer is to that. A brief "hey, I'm here, watch out" doesn't seem like enough, but constant communication also seems like too high of a bar. Worth thinking about.
One additional thought: I could see swarming applications in managing the overall autonomous taxi system. A company with a fleet of autonomous taxis would need to coordinate where they go when not in use (and where they go after dropping off passengers) and may face queueing and coordination problems. Having your taxis communicate and make decisions collectively could offer advantages. For example, taxis at the airport tell taxis in other areas about a sudden spike of activity or collaborate to increase efficiency (autonomous taxi 1 takes the passenger instead of taxi 2 because the passenger 1 is going near the maintenance depot and taxi 1 needs a tune-up). There are probably other advantages as well.
The article below shows the secret service showing off a rat brain sampled into an intelligent container
So there are probably even dogs and chimps being reverse-engineered as we speak, maybe even people.
To answer your question about collisions, locusts were reverse-engineered in the early 2000s.
The locust never collides – despite millions in a swarm, so inheriting that intelligence means no collision.
So if Bell had access to that, yes, a collision-free system could be evolved.
Drones can swarm by each drone emitting a sound that the next key on like grasshoppers
Would this sound be audible? And could a frequency, similar to radars then confuse drones?
How would drone swarms be affected by an EMP weapon
Probably quite poorly, though I do not know enough about EMP hardening (costs; effectiveness) to be more precise. A nuke-based EMP would likely be massive overkill (sort of like mowing the lawn with the dynamite), unless we see swarms on massive scales. Boeing / Raytheon's microwave-based EMP could be workable (https://www.boeing.com/features/2012/10/bds-champ-10-22-12.page) as microwave weapons seem to have a lot of promise against drones as the per-shot costs are low and cover a broad range (https://taskandpurpose.com/air-force-thor-microwave-weapon)
Swarm drones in Colorado and Nebraska. Who's are they?
I am interested in the use of micro drones, swarming and their military application with respect to Cavalry operations.. Typically, reconnaissance, surveillance, and security operations which might include area, route, zone reconnaissance as well as gaining, maintaining contact, limiting enemy freedom of maneuver. I assume they would be linked with unattended ground sensors, satellite communications and possess an information pass back capability. Can you contact me via email?
Happy to discuss further, but I don't appear to be able to see your e-mail address. Feel free to shoot me a note:firstname.lastname@example.org
Re: Military use of Swarmed Drones is an eventuality, however two current major hindrances remain.
First: The A.I. required to assure the swarm remains in a tight formation needs further fine tuning. As the drones adapt to individual missions from the massive swarm, courses and flight desperation must be instigated.
Next: A viable power source that has adequate durability , duration and voltage to complete assigned tasks plus have fractional reserve.
A thought, A.i. Required to keep the Swarmed drones in tight formation and power consumption . It sounds like yours assuming a uniform Drone model, Consider a Russian nesting Doll. or the early thread on the WWII planes. If you had a swarm of larger units containing the coordinating compute, the long range power source, and the long range communication equipment, and a smaller drone swarm contained within to carry out the local mission regardless of the intent of that mission, all they need is a payload, short range communications, and short range propellant. they could be dropped and carry out a mission and then continue on to a central spot for retrieval or be disposable.
You could spend your time and capital protecting your long range transports and your end units become little more than a delivery system.
This concept should work equally well on a civilian side dropping fast moving tracking drones or fire fighting precision loads as on a military environment. The difference would be how and from what you are protecting your transport.
So, how can we coordinate drones in formation without collision. what is the first requirement? I am a UG graduate, it will be very useful to my project if you reply sir