What Are Drone Swarms And Why Does Everyone Suddenly Want One?

Militaries all over the world are moving ahead with swarming attack drones. But what actually is a drone swarm and what makes it so effective ?

Recent weeks have seen a slew of new swarm announcements, including the French Icarus project, the Spanish RAPAZ, The UK’s Blue Bear , the UAE/South African N-Raven as well as a drone swarm hitting targets at India’s Army Day. Last week Armenia, which suffered heavy casualties from Azeri drones in the recent conflict, announced its own new swarming attack drone. Proliferation is well under way even before swarms have been used in action.

Meanwhile the U.S. Marine Corps is progressing kamikaze drone swarms, while the Army, Air Force, Navy and DARPA are pursuing their own separate swarm initiatives, sometimes several simultaneously.

You might assume that a swarm is just a lot of drones in one place, and adding enough makes a swarm. Or you might think that the drones do not become a swarm unless they can all move together, like the impressive, choreographed drone light shows at public events. Neither is quite correct: to make a swarm requires something more.

Thousands of starlings in a murmuration. Software derived from natural flocking and swarming … [+] behavior allows drones to carry out complex co-ordinated maneuvers.

David Hambling

Drone lightshows have a central computer on the ground tracking every single drone and moving them all in unison. The drones’ movements are dictated in a complicated and detailed version of air traffic control which is calculated so that the flightpaths stay separate and no collisions occur. The individual drones take no part in the decision-making process.

A true swarm has no central control. The swarm’s behavior arises form a simple set of rules which each of the participating members follows.

Natural swarming displays take place at higher speed with far greater coordination than drone lightshows. In a murmuration, tens of thousands of starlings carry out complex aerobatics, working together as naturally as part of the same organism (video here). Such shows baffled early researchers – British biologist Edward Selous wrote a book with the title Thought Transference (Or What?) In Birds in 1931. He initially assumed that flock leaders were signaling commands to the rest, but soon saw this was not the case. It seemed to him that the birds shared a group mind : “it seems to be that they must think collectively, all at the same time, or at least in streaks and patches – a square yard or so of idea, a flash out of so many brains.”

Closer analysis, backed up by computer modelling, showed that swarming displays could be replicated if the members just followed a simple set of rules. Artificial intelligence legend Craig Reynolds, who created computer simulations using beings called Boids in 1986. These could mimic the sort of collective movements seen in schools of fish and flocks of birds or swarms of insects with just three rules:

1) Separate: Keep a certain minimum distance from your nearest neighbors.

2) Align: Steer towards the average heading of your neighbors at the same speed.

3) Cohere: Attempt to move toward the average position of your neighbors, keeping the flock together.

Three simple rules developed by Craig Reynolds produce complex flocking behavor for computer … [+] simulations — or real-life drone swarm flight control

Wikicommons – public domain

Reynolds showed how large groups could move toward a destination or avoid obstacles with a seamlessly fluidic agility — there’s a video showing algorithmic flocking here. Reynolds principles were quickly taken up by Hollywood: if you see a flock of CGI birds or bats (or an army of orcs), rather than being individually specified they will be following a swarming algorithm.

Similar de-centralized approaches allow swarms to spread out to search a wide area, or ‘de-conflict’ to ensure they do not all attack the same target. (Note that military drone swarms, unlike lightshow drones or flocking birds, will probably be widely separated).

Even basic swarming makes drones far more effective than working in an unco-ordinated mass. A 2018 U.S. Army study suggested that swarming would make drones at least 50% more lethal while decreasing the losses they took from defensive fire by 50%, but this is just the start.

“Drones may coordinate their target selection, approach, or other angle of attack. For example, in an ‘omnidirectional attack’ swarming drones strike a target from numerous angles,” says analyst Zak Kallenborn — Research Affiliate at the Unconventional Weapons and Technology Division at the National Consortium for the Study of Terrorism and Responses to Terrorism (START). “Communication also would allow drones to share information about target locations and use that to guide attacks.”

And while swarms in nature tend to consist of one type of animal, a drone swarm can incorporate l different types working together, with specialized roles as sensors, attackers, decoys or communicators.

“For example, unarmed drones may collect information from the field to inform armed drones on where best to strike. Drones armed with a combination of guns, bombs, and missiles would allow the drone swarm to use a combination of weapons to carry out an attack,” says Kallenborn. This flexibility would allow each type of target on the ground – vehicle, bunker or personnel – to be engaged in the most efficient way.

“Militaries might add drones equipped for electronic warfare if needed, or maybe add drones with anti-tank missiles. Ideally, drone swarms would be a bit like Legos: mix and match blocks to build the drone swarm the battle commander wants,” says Kallenborn.

This indicates how swarms are likely to be an integral part of DARPA’s vision of Mosaic Warfare in which everything is decentralized and attacks are carried out by a ‘kill web’ rather than manned aircraft or tanks.

Any while current military swarms involve dozens or hundreds of drones, as nature shows much larger swarms are possible, with thousands or tens of thousands of units and proportionately greater destructive power. While current policy calls for lethal drones to remain under human oversight, the inherently autonomous nature of swarming drones means this may become more of an optional extra.

“I expect a global conversation to emerge on the limits of drone swarm technology,” says Kallenborn. States may begin to classify drone swarms as weapons of mass destruction, due to the combination of mass harm and lack of controllability.”

As the spate of recent developments shows, drone swarms are now proliferating rapidly. And while massed drones have been used on the battlefield with considerable effect – such as the attacks in the Abqaiq oil processing facility and the Russian airbase in Khmeimim – drone swarms have yet to be deployed.  Countering large numbers of drones is difficult; countering swarms takes the challenge to another level. What happens next is anybody’s guess.

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