US-China racing to field and counter drone swarms
Recent Chinese air drills revealed defensive challenge of drone swarms, further spurring the race for effective countermeasures
China’s recent air defense drills have highlighted the formidable challenge of neutralizing fast-moving drone swarms, a weapon poised to be a mainstay of future wars and likely deployed by the US in any Taiwan conflict.
This month, the South China Morning Post (SCMP) reported that China’s military recently conducted air defense drills to test its capabilities against drone swarm attacks, exercises that reportedly revealed significant challenges in accurately targeting the small, fast-moving threats.
According to a Chinese state broadcaster CCTV report, the People’s Liberation Army (PLA) achieved just 40% damage in a first round of anti-aircraft artillery launched against a drone swarm.
Duan Xiaolong, from the PLA Ground Force’s 77th Group Army, noted the difficulty in hitting drones due to their speed, small size and ability to change flight trajectories.
The SCMP report says the exercise underscored China’s ongoing efforts to enhance its drone capabilities through investment in more innovative and faster unmanned aerial vehicles (UAVs), part of a global race to develop cost-effective countermeasures to the increasingly sophisticated aerial threats.
In an August 2024 Proceedings article, Karl Flynn highlights the cost dilemma defenders face when using high-end systems like surface-to-air missiles (SAMs) against cheap, mass-produced drones.
Flynn mentions that, as shown by the ongoing Ukraine war, commercial drones with cameras can cost a few hundred dollars, while an Iranian Shahed-136 drone deployed by Russia runs at around US$20,000 per unit.
That compares to the cost of short-range SAMs like the IRIS-T, which runs at around $450,000 per projectile. The disparity means defenders quickly deplete their expensive missile stockpiles against large quantities of inexpensive drones.
Flynn notes that algorithms such as “smart shooter” and “intercept shooter” have limitations in countering sophisticated swarm behavior. He says that the “smart shooter” algorithm, which includes target deconfliction, and the “intercept shooter” algorithm, which uses point-of-intercept navigation, struggle with complex flight behaviors and require significant course corrections.
Further, in a 2022 Joint Force Quarterly (JFQ) article, Jonathan Bell points out that existing counter-drone systems focused on defeating single or small groups of drones are inadequate against the sheer scale and coordination of swarms.
Bell says traditional methods like jamming or kinetic defenses are often too slow or resource-intensive to handle the vast numbers involved. Moreover, he adds the rapid development of drone swarm capabilities, such as the US Replicator initiative, has outpaced innovation in countermeasures, leaving defense systems vulnerable.
The escalating race between drone swarms and anti-swarm defenses exposes the limitations of current defensive measures. Increasingly advanced drones can swarm and outmaneuver existing defenses faster than they can keep up.
In a 2024 JFQ article, Zachary Kallenborn and Marcel Plichta note that a drone swarm’s power lies in its sheer numbers and the complex, decentralized coordination that allows it to adapt dynamically during engagements.
Kallenborn and Plichta mention that drone swarms can exploit gaps in defensive coverage, saturate interceptors and even use decoys to confuse and deplete a defender’s resources.
For example, they say that drone swarms can execute saturation attacks where large numbers of drones target a single defense system, forcing it to exhaust its ammunition or energy reserves, thereby leaving the primary targets unprotected.
They add that drone swarms can integrate diverse tactics, such as using one group of drones to draw fire while another strikes the weakened defenses.
On the other hand, Kallenborn and Plichta say that defending against these swarms involves multiple layers of technology and tactics. They note that kinetic weapons, like anti-aircraft guns and missiles, can be effective but may become overwhelmed by the swarm’s numbers.
They say that directed-energy weapons, like high-energy lasers and high-powered microwaves, provide a cost-effective and versatile option, but their performance can be affected by environmental conditions and advancements in drone defenses such as protective coatings.
Kallenborn and Plichta note that while jamming and spoofing can disrupt the swarm’s coordination, these methods are limited by the drones’ increasing autonomy and ability to navigate using alternative systems.
Despite that situation, Daniel Shats and Peter Singer mention in a November 2023 Defense One article that China is advancing its counter-drone technologies to neutralize US drone swarms, as highlighted at the Zhuhai Airshow last year.
Shats and Singer say that the LW-30 laser defense system, developed by China Space Sanjiang Group, is a critical innovation that can down small drones several kilometers away using a 30-kilowatt beam. They mention that this system, which reportedly costs around U1.75 per shot, exemplifies China’s focus on cost-effective, directed-energy weapons.
They say China’s HQ-17AE short-range air-defense system, presented by CASIC’s Second Academy, combines missiles, radar and electronic jamming to target multiple airborne threats, focusing on improving early-warning and interception capabilities through its three-dimensional network design.
In addition, Shats and Singer mention that China’s military-industrial complex, led by entities like CASIC, Poly Technologies and CETC, is also developing high-power microwave weapons and autonomous counter-drone systems.
Kristopher Thornburg points out in a December 2022 Proceedings article that while countering drone swarms is a challenge, the best putative counter to an expendable drone swarm is another expendable drone swarm.
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In line with that, Matthias Brust and other writers mention in a December 2021 articlein the Discover Internet of Things peer-reviewed journal that counter-unmanned aerial systems (C-UAS) represent an innovative approach to defending against malicious UAVs (mUAVs) in increasingly congested airspaces.
Brust and others’ concept revolves around deploying a swarm of defense UAVs (dUAVs) that autonomously and collaboratively form a three-dimensional cluster around the intruding mUAV. They say this cluster restricts the mUAV’s movement, eventually escorting it out of the contested flight zone.
Significantly, this system operates independently of GPS, enhancing its resilience against communication loss and other disruptions.
Brust and others note critical features of the system, including balanced clustering, which ensures that the formation remains effective even under dynamic conditions, and the use of local formation control to adapt to real-time threats.
They note that the defense swarm’s modular design comprises patrolling, detection, interception and counter-attack phases that neutralize the mUAV threat.
Brust and others say that simulations show that the system can effectively capture and guide hostile drones, with its performance affected by factors like communication range and UAV stability.
They note this approach provides a scalable and flexible solution to combat the increasing risk of unauthorized UAVs and minimizes potential collateral damage compared to conventional ground-based systems.