Drones are just beginning to rewrite the rules of warfare, but their nemesis may have emerged

Drones have in fact changed the "rules of the game" of modern warfare by using "unmanned" to strike "manned" with asymmetric strike capabilities. Countries are exploring ways to restrain this rule changer. Microwave weapons will become an effective means of countering drones and their clusters due to their advantages such as speed of light attack, strong area killing capability, and high cost-effectiveness.

Written by Cui Kai (Director of the Science Communication and Popularization Committee of the Chinese Society of Aeronautics)

A small drone hovered above the huge Israeli main battle tank "Merkava MK4" and quickly released the RPG-7 rocket hanging on it. The rocket exploded on the top of the tank, which was the most vulnerable part. In an instant, flames shot up into the sky and thick smoke billowed.

This is a video that was exposed in mid-October 2023 [Go to "Fanpu" to watch], showing Hamas drones hunting down Israeli "Merkava" tanks. The video quickly attracted onlookers and surprise among military fans. You know, the "Merkava" MK4 is known as the main battle tank with the strongest survivability in the world. It has outstanding armor protection capabilities and is equipped with an active defense system that can resist attacks from anti-tank missiles and high-powered anti-tank rocket launchers. However, it was easily broken by a small drone.

This case once again proves that under the surveillance of various types of drones, the survivability of ground heavy equipment, including main battle tanks, is becoming increasingly worrying.

In fact, in several recent local wars, including the Russian-Ukrainian conflict, drones have begun to play an increasingly important role. From the actual combat effect, the asymmetric strike capability of drones with "unmanned" against "manned" has in fact changed the "rules of the game" of modern warfare. In this context, how to effectively deal with the threat of drones and develop corresponding countermeasures based on their characteristics has become one of the primary development directions of countries around the world, especially developed countries. There are currently a variety of drone countermeasure technology development routes, among which microwave weapons are unique in drone defense with their significant characteristics.

01

How Drones Are Changing Modern Warfare

Since the Gulf War in the 1990s, the precision strike mode with precision-guided munitions as the main equipment has gradually become the dominant mode of modern warfare and has been frequently used in many local wars such as Iraq and Afghanistan. This strike mode has the advantages of wide coverage, diverse launch platforms, accurate attack targets, and high intelligence. However, this mode also has obvious shortcomings, including only being able to achieve point-to-point attacks, requiring system coordination, and not being suitable for attacking densely populated areas or street fighting. In addition, precision-guided weapons are expensive, with the price of a single missile often easily reaching millions of dollars, or even tens of millions of dollars, which places extremely high demands on the economic support capabilities of the belligerents in a war of attrition.

The emergence of drones has had a severe impact on this model. The drones currently in use mainly include fixed-wing and rotary-wing drones, which are easy to carry, flexible to use, and have a variety of uses. Drones used by individual soldiers generally weigh only a few kilograms and are easy to put into a combat backpack and carry. At the same time, they also use advanced navigation and positioning systems, which can perform high-precision autonomous navigation and positioning in complex environments. In actual combat, drones can carry small missiles or bombs to attack, and their strike accuracy and power are very powerful. At the same time, drones can also conduct combat assessments, that is, reconnaissance and analysis of the enemy's combat effectiveness, deployment, and actions, providing important reference for subsequent operations.

In addition to their outstanding combat capabilities, the biggest advantage of drones is their low price. Due to their simple design and high degree of commonality of parts, their R&D and manufacturing costs are low. For example, the U.S. military's "Coyote" drone, most of its fuselage is made of composite materials and modular design, and the cost of a single unit is only $15,000. The cost of some weapons modified from civilian drones can even be reduced to a few hundred dollars.

On this basis, the use of a certain number of drone clusters will form a drone "swarm" that is even more terrifying. The "swarm" is composed of multiple low-cost drones with a high degree of intelligence, and they can communicate and coordinate with each other when performing tasks. They can not only strike multiple targets at the same time, but also repeatedly strike a single high-value target. Due to its numerical advantage, cluster attacks can be launched from multiple angles and directions in a short period of time, quickly saturating the enemy's air defense and anti-missile system detection, tracking and interception capabilities. The "swarm" drones are small in size and have small radar signal characteristics, making them difficult for the enemy to detect and discover. They can be quickly launched from a variety of platforms such as fighters, ships and vehicles, making it easy to launch concentrated attacks instantly, achieving the effect of attacking the enemy by surprise and being unable to defend against them.

The U.S. military is testing drone swarms.

02

Who can control drones?

As drones and their swarm system combat modes gradually become an important style of future wars, the development of effective countermeasures has gradually received great attention from all countries. Take the United States as an example. Since 2015, the US military has increasingly attached importance to the development of anti-drone systems. From fiscal years 2019 to 2021, the average annual investment was about US$500 million. In fiscal year 2023, the US Department of Defense spent another US$668 million on the research and development of anti-drone systems, and at least US$78 million on procurement.

The process of countering drones can be mainly divided into two stages: detection and attack. First, the target drone is detected, tracked and warned, and then the corresponding damage means are taken according to the actual situation. Common damage means include: 1) using anti-aircraft guns and anti-aircraft missiles for hard killing. Although this method has high technical maturity, it is also costly; 2) using nets from the ground or air to capture drones by physical capture. This method is low-cost and simple to implement, but the hit rate is low and the effective range is very limited; 3) using combat drones to fight drones has the characteristics of high precision and small collateral damage, but the technical maturity is relatively low, and generally only point-to-point attacks can be achieved, and the lethality to swarm systems with self-repair capabilities is limited; 4) using high-energy laser weapons to directly kill targets. This method has the characteristics of fast response, high precision and great power, but its effectiveness is greatly affected by the target material and weather, and it is generally ineffective when dealing with large swarms.

In contrast, microwave weapons under development may become the nemesis of drones, especially drone swarms. Microwave weapons refer to combat weapons equipped with high-power microwave (HPM) payloads, which can be carried on a variety of platforms such as land-based, air-based, sea-based, and even missile-based. The damage principle of microwave weapons is similar to that of common microwave ovens, that is, they continuously emit electromagnetic pulses, which couple through the back door (holes, etc.) of the drone to disrupt the drone's flight control system, or couple through the front door (microwave receiving channel) to damage the drone's measurement and control receiver, causing the drone to lose control or be damaged depending on the size of the coupling energy.

Compared with other means of destruction, microwave weapons have unique advantages in countering UAVs and their clusters.

First, it has a wide killing area, can kill multiple targets in the area at the same time, and does not require high precision in the guidance system. For example, the "Tactical High Power Operational Responder" (THOR) anti-swarm electromagnetic weapon developed by the US Air Force Research Laboratory can shoot down more than 50 drones at a time in actual tests.

Second, the attack time is short. Microwaves travel at the speed of light and have a high energy density, which can cause damage to the target within microseconds. For example, the land-based "Onidas" system launched by the US Epirus company in 2020 successfully shot down all 66 drones in a prototype demonstration in February 2021 in just a few minutes.

Third, microwave wavelengths are longer than lasers, are not sensitive to weather, and can be used around the clock.

Finally, the cost-effectiveness is extremely high. When fighting against drones, it only consumes electricity and can be used repeatedly.

Based on the above advantages, high-power microwaves can achieve wide-area killing and efficient confrontation against drones and their clusters, and have gradually become the "nemesis" of drones.

03

Current status of microwave weapons research and development

In fact, microwave weapons were not designed to counter drones. Relevant research began in the 1970s, when they were mainly designed for electronic warfare, interfering with enemy communication systems or damaging their sensors and important electronic components by emitting high-power microwaves, thereby implementing electronic interference or destroying enemy electronic equipment.

Early research on microwave weapons mainly focused on the exploration of high-power microwave sources and the killing mechanisms of high-power weapons. After entering the 1980s, related theoretical research made breakthrough progress, and equipment research began to shift from the laboratory stage to the practical stage. In the 1990s, application-driven high-power microwave research projects began to appear. Since the new century, it has gradually transitioned towards military platforms and offensive weapons.

The United States has made the most significant progress in this field. Their strategy is to develop weapon prototypes based on the development of high-power microwave technology, demonstrate and verify them at test sites, and even use them on the battlefield. For example, in the Gulf War, the U.S. military used the Tomahawk cruise missile as a bomb-carrying platform to drop experimental microwave bombs, and used it again in the Kosovo War to carry out information strikes against the Federal Republic of Yugoslavia.

In recent years, with the increasing threat of drones, as one of the important branches of microwave weapons, research projects related to anti-drone or swarm systems have continued to increase. The following introduces some key projects:

Phaser High Power Microwave Weapon System

"Phaser" high-power microwave weapon system.

The "Phaser" high-power microwave weapon system was developed by Raytheon Company of the United States. It is a diesel-powered land-based microwave weapon system used for anti-UAV and other tasks. The entire system is installed on a 20-foot-high container. Under the guidance of the search radar, it can continuously track the location of the UAV target. During the process, the dish antenna transmits high-energy microwaves in a directional manner to burn the electronic components inside the target. In September and October 2013, the US Army successfully used this system to conduct air defense tests to intercept small UAV targets at Fort Sill, Oklahoma.

Tactical High Power Microwave Operational Responder (THOR)

"Tactical High Power Combat Responder" system.

The Tactical High Power Combat Responder was jointly developed by the U.S. Air Force Research Laboratory, BAE Systems, Leidos and VerusResearch to develop a new type of air force base anti-swarm threat weapon.

In February 2021, the U.S. Army Rapid Capabilities and Critical Technologies Office signed the THOR program and will cooperate with the U.S. Air Force to provide a fire protection high-power microwave system around 2024 and equip a platoon. In July 2021, the U.S. Air Force Research Laboratory revealed a plan to develop a new high-power microwave weapon system prototype, which is called Mjolnir. Although the technology used in Mjolnir is basically the same as THOR, it will be different and breakthrough in capability, reliability and manufacturing.

Leonidas anti-electronic system

Land-based Oneidas system.

Epirus, a US company, launched the land-based "Oneidas" system in 2020, claiming it to be the world's first miniaturized high-power microwave system. Epirus is expanding the system's capabilities to adapt to different mission requirements, including the development of a series of high-power microwave weapons such as individual, ground-mobile, drone-mounted pods, and ship-borne types. In October 2021, General Dynamics Land Systems of the United States reached a cooperation with Epirus to integrate the "Oneidas" anti-electronic system into Stryker combat vehicles and other manned/unmanned ground vehicles to defend against drones, swarms and other electronic threats, and enhance the US Army's short-range air defense capabilities.

MORFIUS System

MORFIUS system.

The MORFIUS system is a reusable high-power microwave interceptor designed and developed by Lockheed Martin specifically for countering drones/aircraft swarms. The system is capable of destroying multiple drones at once in the air without causing damage to the ground, vehicles, etc. The system supports layered defense and can be integrated into any command and control network through open interfaces. It is reported that MORFIUS has conducted more than 15 test activities since 2018, and will continue to conduct more tests in the future to demonstrate its end-to-end capabilities.

In addition, Russia has also been deeply involved in the field of microwave weapons for nearly 10 years. In 2014, the Russian Radio Electronics Technology Group (KRET) developed the "Krasukha" series of electronic warfare weapons, of which the "Krasukha"-4 system is the latest high-power microwave jamming system in the series. The vehicle-mounted "Krasukha"-4 system can counter the US E-8C battlefield surveillance aircraft, "Predator" unmanned reconnaissance and attack aircraft, and "Global Hawk" unmanned strategic reconnaissance aircraft. It is reported that each Russian military district usually has two independent electronic warfare companies, and one of the companies is equipped with the "Krasukha" system.

Russia's Krasukha series of electronic warfare weapons.

04

Future Development Direction of Microwave Weapons

In summary, high-power microwaves will become an effective means of countering drones and their clusters due to their advantages such as speed of light attack, strong area killing capability, and high cost-effectiveness. Through research and analysis, the main development trends in technology and equipment in the future are as follows:

1) From a technical perspective, it is urgent to further improve the energy conversion efficiency of microwave systems. At present, high-power microwave weapon prototypes generally have shortcomings such as limited strike range, low maneuverability, and slow response speed. The key to the problem is that its high-power microwave generation system is relatively large and bulky, and the fundamental reason is the low energy conversion efficiency of the microwave system.

2) From the perspective of equipment development, lightweight, miniaturization and modularization of weapon systems will be the next development direction. Considering the need to adapt to different combat environments and combat missions in future wars, microwave weapons and equipment should be adapted to various platforms such as land-based, sea-based and air-based, and achieve multi-dimensional strikes against drones and swarm systems. This requires the system to have the characteristics of light weight, small size and flexible combination.

3) From the perspective of system functions, intelligence, multi-function and platform coordination will be the future development direction. As the intelligence level and stealth capability of UAV systems continue to improve, it is becoming more and more important for microwave weapon systems to quickly identify targets intelligently. At the same time, the system is also required to have multiple functions such as detection and tracking, early warning, maneuvering, aiming and launching to achieve rapid defense. This not only requires improving the integration level of the microwave weapon system itself, but also requires coordinated use with the carrying platform to maximize its advantages.

References

[1] Zhao Hongyan, Zhou Li. Research on the development of foreign high-power microwave weapons. Aviation Weapons, 2023, 30(4): 42-48

[2] Ling Junpu, Wang Lei, Pi Mingyao, et al. Research status and implications of US anti-UAV high-power microwave technology. National Defense Science and Technology, 2023, 44(3): 74-80

[3] Huang Mingrui, Zhao Guolin, Pan Xiaodong, et al. Current status and development trend of foreign anti-UAV swarm research. Ship Electronic Engineering, 2023, 43(7): 1-3

[4] MoRFIUS: an airborne HPM counter-UAS asset by Lockheed Martin. https://www.edrmagazine.eu/morfius-an-airborne-hpm-counter-uas-asset-by-lockheed-martin

This article is supported by the Science Popularization China Starry Sky Project

Produced by: China Association for Science and Technology Department of Science Popularization

Producer: China Science and Technology Press Co., Ltd., Beijing Zhongke Xinghe Culture Media Co., Ltd.

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