UAV interception technology classification and analysis of omnidirectional suppression equipment characteristics

In recent years, the UAV interception technology has developed rapidly, showing a situation in which hundreds of flowers bloom and hundreds of schools contend. Among them, the most widely used ones in the world are omnidirectional suppression devices. This paper starts with the classification and current situation of UAV interception technology. Firstly, it expounds the UAV suppression interference from the technical principle, and then analyzes the equipment from the perspective of parameters and application characteristics, aiming to provide certain development for the good development of this technology. Ideas and suggestions.

I. Classification and current status of UAV interception technology

UAV interception technology (also known as anti-UAV technology) refers to the systematic technology used for UAV interception. Because drones may pose a serious threat to civilian and military installations, governments in recent years have become increasingly concerned about the potential security threats to drones. In fact, the new market for anti-UAV technology is also rapidly and rapidly emerging [1].

In September 2017, the Department of Public Security of the Ministry of Public Security and the Special Police Equipment Quality Supervision and Inspection Center of the Ministry of Public Security conducted a field survey of UAV detection and interception equipment in Lianyungang. A total of 122 units (sets) of 91 units in China were tested. According to the technical route of the test equipment, it is divided into detection (radar, photoelectric) system, wireless detection and positioning equipment, suppression (directional or omnidirectional) interference equipment, deceptive interference equipment, damage (net capture or laser) equipment and the above technology integration. system.

For the UAV interception technology, the author classifies and combines the existing technologies according to the different interception techniques through the following research:

Table 1 UAV interception technology classification

As can be seen from Table 1, the existing UAV interception technology presents a wide variety of features and technical diversification. Because of the characteristics and limitations of various technologies, the combination technology mentioned at the end of Table 1 has become the development trend of current UAV interception technology.

In the actual application process, the user side generally pays more attention to the tactical technical indicators of the UAV interception system. Therefore, from the perspective of practical application, this paper classifies the system (device) mentioned above as shown in Table 2 as follows:

Table 2 UAV interception system classification (platform type division)

From the current situation of China's domestic equipment development, the ground-mounted, vehicle-mounted and hand-held systems (equipment) mentioned in Table 2 account for more than 90%. Currently, the airborne equipment of drones is limited by volume and weight. Mainly used in the field of militarization.

Second, the principle of unmanned aircraft suppression interference interception technology

2.1 Communication interference technology

In UAV communication, it is generally impossible to completely suppress external interference and other signals whose characteristic parameters are the same as or similar to the useful signal while receiving the useful signal, so that there is bound to be an uncertain factor when the communication receiving system detects the useful signal. By using this feature, the interference signal can be artificially applied, and the amount of useful information obtained by the signal receiver of the drone is forced to be reduced to reach the purpose of interception [2].

Because of the many hazards of drones, drone interception technology came into being. Among the existing intercepting methods, the radio communication interference technology has been widely used because of its obvious intercepting effect and small incidental damage. For this technology, its characteristics can be summarized as follows [3]:

(1) confrontational

Communication interference is to disrupt or disrupt the other party's radio communications. The purpose of radio communication interference transmission is not to transmit certain information, but to use interference information carried in the interference to suppress and destroy the other party's communication. Communication interference is aimed at the other party's communication system, which is very clear.

(2) Offensive

Radio communication interference is active, active, and active. It does everything possible to "kill" into the communication system of the other party, so communication interference is offensive. Even communication interference for defensive purposes is offensive.

(3) Advanced

Communication interference is targeted at the other party at all times, so it must track the new development of the other party's communication technology, and must try to surpass each other, in order to develop a communication interference device that defeats the enemy. However, the development of communication technologies in various countries in the world, especially the development of anti-jamming technologies, is carried out under highly confidential conditions, and it is difficult to detect such information. Therefore, radio communication interference is a very high-tech, very difficult and difficult task in the high-tech peak of radio communication.

(4) Working frequency bandwidth

Radiocommunication Interference Equipment With the development of modern radio communication technology, the range of frequencies that need to be covered has been quite wide, even reaching dozens of kilohertz to tens of gigahertz. In such a wide operating frequency range, electronic technology and electromagnetic wave radiation and reception have different characteristics and requirements in different frequency bands.

(5) Fast response

In today's rapid development of frequency hopping communication and burst communication, the target signal has been short-lived at a frequency point. In such a short period of time, the search, interception, identification, sorting, processing, interference guidance and interference transmission of the target signal should be completed within the entire working frequency range. It can be seen that the response speed of the communication interference system must be very rapid.

(6) High technical difficulty

First, communication devices typically have strong signals, so strong interference is required for interference and suppression of communication signals. Secondly, the communication is generally carried out in a narrow band, so the frequency of the communication interference requires a higher accuracy. Because of these two characteristics, communication interference has certain technical difficulties, and it is necessary to continuously update and adjust the interfered targets.

2.2 Introduction of suppression interference technology

Interference interception technology can be divided into two types: suppressed interference and deceptive interference according to different technical principles [4]. As a name suggests, suppressive interference is a form of interference that obscures the spectrum of the unmanned signal by transmitting an interference signal, causing its communication receiver to reduce or completely lose its normal working ability. Deceptive interference is the conscious intention to "send" the simulated false signal into the communication network of the drone by imitating the communication signal of the drone, causing communication errors or operational errors.

Pressed interference can be divided into the following four categories according to the spectral width of its signal [5]-[6]:

A) Aiming interference. The aiming interference means that the carrier frequency (center frequency) of the interference coincides with the signal frequency, or the spectrum width of the interference signal and the communication signal are the same. For example, if a station sends a report to the station, the effect of the interference is that the station cannot receive or hear the message from the station. Therefore, the narrow-band spectrum radiated by the aiming interference must be substantially the same as the frequency band of the signal sent by the station, and enter the selection circuit of the receiver of the station at the same time as the signal sent by the station.

The power of the aiming interference is concentrated, the interference frequency band is narrow, and the interference energy is all used to suppress the communication signal of the other party, and the interference power utilization rate is high, and the interference effect is good. However, the frequency reciprocity is required to be good, the performance of the jammer is high, and the detecting portion for guiding the interference frequency is required.

Aiming interference, usually each interference frequency is aligned with a corresponding communication signal frequency to implement interference, but the situation that one machine interferes with multiple targets has been gradually applied. In general, aiming interference is used in the short-wave band to suppress important communications from the other party.

B) Semi-aiming interference. Compared with the aiming interference, the semi-aiming interference has a poor accuracy of frequency coincidence, that is, the interference signal spectrum does not completely coincide with the communication signal spectrum. Usually the spectrum of the interfering signal is wider than the frequency bandwidth of the suppressed communication signal. The interference spectrum can pass through the frequency selection loop of the receiver of the other party. Although the spectrum of the other party signal does not necessarily coincide or the frequency coincidence degree is not high, a certain degree of interference can be formed.

Because the semi-aiming interference power is not concentrated, the utilization rate is low, and it is only used under special circumstances. If the other party's signal appears for a short time, it is too late to aim, or for some communication methods, it does not require accurate frequency coincidence and can achieve better interference effects.

C) Blocking interference. Blocking interference, also known as blocking interference, has a wide spectrum of interference radiation and usually covers the entire working frequency band of the other communication station. Blocking interference can be divided into continuous blocking interference and comb blocking interference. The continuous blocking interference transmits the interference signal in the entire frequency band, and simultaneously suppresses the communication signal in the frequency band; the interference frequency band of the comb-shaped blocking interference is comb-shaped, and the communication signals falling into these frequency bands are interfered. The interference band can be fixed or mobile.

Blocking interference is a kind of detection device that does not need frequency recombination equipment and does not need to guide interference. The equipment is relatively simple and can simultaneously suppress multiple communication stations in the frequency band. However, its shortcomings are: first, the interference power is dispersed and the efficiency is not high; secondly, when the blocking interference is applied, the communication signal of the own party falling within its frequency band will also be interfered. Blocking interference mostly works in the ultrashort wave range.

D) Swept interference. Swept interference refers to the interference caused by the carrier's carrier frequency in a wide frequency band from the low end to the high end, or from the high end to the low end.

Swept interference systems are highly automated interference systems. The pre-interference channel is stored in advance by preset, and is repeatedly scanned within a certain frequency range, and when the signal of the preset channel appears, automatic random interference can be performed. This kind of interference has the characteristics of short interference reaction time, interference in maneuvering, and automatic management mode.

Third, equipment features and application scenarios

From the point of view of use, the widely used UAV interception equipment in the world is a suppression interference device, which plays an extremely important role in the field of battlefield and social public safety. For this type of equipment, the interception effect is good as an omnidirectional pressing device.

The omnidirectional pressing device, as its name implies, can release high-power suppressed interference signals to the horizontal 360° range of the device without direction. The following Figure 1 shows a typical omnidirectional pressing device.

Figure 1 Omnidirectional pressing equipment (ground mounting type)

Take China's market as an example, the vast majority of UAVs in the market use frequencies not exceeding 1575MHz ± 10MHz, 2408-2440MHz, 5.725-5.850GHz (5725-5850MHz), so almost all UAVs on the market These three frequency bands are included in the suppressed interference products.

On this basis, omnidirectional compression equipment usually also includes some wireless communication equipment (such as walkie-talkies, cordless phones, etc.) frequency bands and common remote control dangerous goods frequency bands, so such equipment is usually characterized by strong versatility.

From the current use situation, because this type of equipment usually has a large transmission power and a wide coverage area, it is usually suitable for interception of strong interference drones for special occasions, such as militaryized places, nuclear power plants and prison car escorts.

Figure 2 Omnidirectional pressing equipment (vehicle type)

Figure 2 shows a type of vehicle-mounted omnidirectional pressing equipment. This type of equipment is widely used in the military and police fields in the world, and has played a good practical effect.

Fourth, the parameters and advantages and disadvantages analysis

4.1 band resolution

In order to effectively intercept UAVs of different frequencies, UAV omnidirectional compression devices can usually transmit suppressed interference signals in multiple frequency bands. Through the special police equipment quality supervision and inspection center of the Ministry of Public Security, the common UAV omnidirectional suppression equipment frequency band is sorted out, and the typical frequency bands of such equipment are roughly counted (shown in Figure 3).

Figure 3 UAV omnidirectional suppression device frequency band statistics

It can be seen from Figure 3 that the domestic UAV omnidirectional pressing equipment basically covers the typical frequency bands controlled by Chinese and foreign UAVs. At the same time, such equipment usually has some atypical UAV control frequencies. Let me repeat.

4.2 Equipment limitations

Because the omnidirectional pressing device is a target signal of high power pressure drone, it needs a large transmitting power on the basis of ensuring the working range and effective working distance, and the radiation intensity of the human body is large during work, and it is easy to exceed the national limit range. . According to the provisions of GB8702-2014 "Electromagnetic Environment Control Limits", the electric field strength limit is not more than 12V/m. From the data of 8 typical equipment radiation intensity statistics collected by the testing center, such equipment usually has excessive radiation values. Some products are seriously exceeding the standard, see Figure 4 below.

Fig.4 Statistics of radiation values ​​at 1m of UAV omnidirectional pressing equipment

As can be seen from the above figure, the radiation values ​​of the eight typical UAV omnidirectional pressing devices at 1m are excessive. The radiation exceeding the standard is 214v/m, which is more than 16 times higher than the national standard, and the radiation intensity is low. The test value of one device also reached 25.7v/m, more than double the national standard.

In addition to the above-mentioned shortcomings of radiation exceeding the standard, such equipment will cause strong interference to the same-frequency electronic equipment in the range of motion due to the omnidirectional transmission of interference signals. Therefore, it is necessary to use such as audio, stage remote control, etc. for large-scale events. This type of device is generally not recommended for UAV interception when using wireless devices.

V. Conclusions and prospects

This paper starts with the classification and current situation of UAV interception technology. Firstly, the existing technical means are analyzed and classified according to the interception technology route, and then the system (device) is differentiated by the application platform. Next, this paper expounds the suppression interference interception of UAV from the perspective of technical principle, and analyzes the frequency band and application scenarios of this type of equipment. Finally, this paper analyzes the shortcomings of such devices from the perspective of practical application, and introduces the limitations of such devices.

It can be seen from the comparison of the data in this paper that the radiation intensity of this type of equipment is large and there are serious cases that exceed the national security restrictions. Therefore, it is only suitable for special scenes and special occasions. Only by continuously reducing the radiation hazard of equipment can the technical advantage be better To provide protection for low-level public safety. (Author: Dr. Li Mu)

references

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[3] Xiao Cong. Research and verification of radio signal suppression interference. University of Electronic Science and Technology, Master's Thesis, 2010, (5).

[4] David L. Adamy, Yang Caiyi, etc. Communication Electronic Warfare. Beijing: Publishing House of Electronics Industry, 2017.

[5] (US) Richard A. Poisel, No. Equivalent Translation. Introduction to Communication Electronic Warfare System. Beijing: Publishing House of Electronics Industry, 2003.

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