In recent years, drone swarms have been involved in many extreme incidents, including disrupting airports, attacking military bases, and raiding large oil fields. The huge potential for drone swarms in battlefield applications has prompted military powers around the world to increase their investment in research and development, striving to expand their asymmetric advantages over the enemy in order to seek the initiative in future wars.

Types of Drone Swarm Threats

 Classification of drone swarms

Based on the anti-UAV swarm characteristics, drone swarm types are divided into three categories.

No autonomous space-time coordination:This type of drone swarm does not have autonomous capabilities, relies on early pre-programming, and adopts time and space coordination. It is mainly based on multi-rotor drone platforms. It has a low technical threshold. A typical representative is the drone swarm widely used in light show performances.

Semi-autonomous teaming:This type of drone swarm has semi-autonomous capabilities and is in a "man in the loop" state. It is mainly based on homogeneous/heterogeneous drone platforms for grouping and coordination. It has a high technical threshold and is a focus of research now and in the next few years.

Fully autonomous task coordination:This type of drone swarm has complete autonomous capabilities and is in a "man out of the loop" state. It can coordinate tasks without relying on communication links to achieve autonomous reconnaissance and attack. It is the highest form of autonomy for drone swarms and has extremely high technical barriers. Based on current technological levels, it will be difficult to achieve in the short term.

Feasibility analysis of drone swarm countermeasure technology

According to the tactical characteristics and weaknesses of drone swarms, we eliminated technologies with low counter-effectiveness and specifically analyzed an effective anti-drone swarm technology system.

Link interference

1. Accusation link interference and deception

(1) Suppressive interference. This is the main method of interference in the command and control link. The technology is relatively mature, the cost is low, the system operation is simple, and the interference effect is significant. The cluster architecture of the self-organizing network has a certain degree of network self-healing. The interference equipment must meet the interference conditions of wide frequency, high power, and omnidirectional. The interference is difficult and has a great impact on the surrounding frequency-using equipment. There is collateral damage and it needs to be used with caution.

(2) Electronic fence

This is a method taken to prevent drone swarms from entering a specific area. It is technically simple and low-cost, and has the advantages of unmanned operation and high flexibility. It can be used as an important terminal protection measure.

(3) Control signal interference. This type of method can be divided into two types.

The first is communication link hijacking, which involves long-term monitoring, analyzing and deciphering the key parameters of the communication data link of non-cooperative target drones, such as the working frequency band, protocol, and encryption, and sending false control commands to drones to implement deceptive control. The second is forwarding tracking interference, that is, once the enemy's command link signal is detected, it is quickly forwarded at the same frequency or with a delay; it can also disrupt its battlefield operations by randomly changing the signal coding, such as changing one of the binary codes.

2. Navigation link jamming and deception

Unlike a single drone, a drone cluster can use two or more combined navigation methods such as GPS, BDS, Galileo and GLONASS due to its distributed functions.

In the following situations, navigation link interference and deception are not effective: ① GPS military code navigation is used, and navigation deception is ineffective; ② There are high-precision inertial navigation systems (INS) or laser gyroscopes and other navigation equipment inside the drone cluster. Once the navigation is interfered or the navigation deception error exceeds the threshold of INS, it will switch to pure inertial navigation mode, making the navigation link interference and deception methods ineffective.

Comprehensive protection

In general, it is difficult to counter drone clusters, and there is no countermeasure system that can achieve 100% interception. For important core targets, the countermeasure principle should be based on protection. At present, daily key point protection is mostly concentrated on two-dimensional plane protection, lacking protective measures against air threats. Three-dimensional protection of key weak points should be strengthened to improve overall anti-destruction capabilities.

Active countermeasures

Under the traditional passive defense mode of thinking, anti-UAV swarm operations have problems such as delayed situational awareness, limited defense range, and limited movement of countermeasure equipment. Anti-UAV swarm technology based on UAV platforms has the advantages of active defense, air-ground coordination, flexible deployment, strong mobility, and precision and efficiency.

Overall, the development of existing UAV swarm countermeasure technology lags behind the development of UAV swarm technology. In the face of the increasingly urgent threat of UAV swarms, we should base ourselves on the existing UAV swarm countermeasure technology, adhere to joint operations and system operations as breakthroughs, and be guided by the needs of anti-UAV swarms. We should carefully plan reconnaissance and early warning, joint interception, network and electronic countermeasures, and comprehensive defense operations, and use system advantages to make up for the shortcomings of existing technologies.