Technology comparison of “low, slow and small” uav detection and countermeasures system

In recent years, the civil unmanned aerial vehicle (uav) technology is becoming more and more mature. While the application is more and more extensive, the control accidents and related safety problems caused by the civil unmanned aerial vehicle (uav) are becoming more and more normal. While the civil unmanned aerial vehicle (uav) has many beneficial application prospects, it may also be used more and more maliciously.

With the rapid development of China's economy and society, the number of important places such as information network, power network, nuclear power plant, energy base, transportation hub, large water conservancy facilities, government agencies and so on has been increasing and more widely distributed. In addition, China's economic strength increased, increasing the external exchanges, the more and more large-scale activities, and presents the characteristics of large scale, high specification, and often in high population density, buildings density of political and economic center, because of the important facilities and events surrounding the construction environment, electromagnetic environment and meteorological environment, traffic environment is very complicated, therefore, prevention and treatment is given priority to with multiple uav rotorcraft uav target accidents and terrorist attacks will be very difficult.

In summary, illegal drones may pose a potential and realistic threat to public safety and normal production and life order, which can be divided into three aspects:

1. Voyeur in the air

The flying height of the uav surpasses most obstacles, and it can easily take photos and video of the key parts of the high wall courtyard. Uav has relatively complete camera stabilization technology, flight recording system, real-time image return system, and has the functions of fixed point cruise shooting, following shooting and circling shooting. It can be used for stealth activities without modification.

2. Dangerous "transfer station"

Due to the tight security on the ground around major events or important facilities, the prevention and control measures are in place, so lawless elements may carry explosives, biological agents, radioactive materials or illegal propaganda by unmanned aerial vehicles into the stadium. Using GPS navigation technology, even in the dark of night, the drone will be able to jump over the walls and fences of the target area and deliver hazardous materials to the designated place without alerting guards or alarm equipment. The drone bomb aimed at the President of venezuela is a wake-up call.

3. Uncontrollable risks

Model aircraft or some aerial amateur, and even ordinary people, for entertainment, curiosity or not, the drones fly over to the active site or important areas, over the past few years in some sensitive areas, such as civil aviation airport, prison wharf, important materials warehouse, office, the meeting, and so on, all have caused by micro uav into chaos phenomenon, and even cause significant losses (such as civil aviation airport a few years ago the forbidden black fly empty area).

At the same time, in addition to the risk of illegal entry of the uav itself, in these key places, the poor quality of the DIY uav itself and the control reasons may lead to the occurrence of air collision, fall, fire, explosion and other accidents, will also pose a great danger.

Therefore, for this kind of low and slow small uav's prevention or called the counter system, also emerged.

Main technologies of uav countermeasures system

For the low and slow small uav counter system, there are mainly detection and counter two parts. Among them, for detection, there are spectrum detection type and radar detection type two technical systems. For counter-countermeasures, there are more technical systems, such as suppression jamming, spoofing jamming, physical destruction, direct capture, and so on. But suppression and spoofing will be covered in either system, because using radio suppression and spoofing is the fastest, most cost-effective technology for small, low and slow uavs. The following is a brief introduction to each of these techniques.

1. Radio jamming system

As mentioned above, for "low, slow and small" uavs, squashed radio jamming may be the most direct and cost-effective way to counter them. In fact, it is to suppress and interfere with the remote control link, information transmission link and GPS navigation signal of illegal uav by radio, so as to make the illegal uav blind, deaf and mute in a certain area. Even with the role of drone inertial navigation, it can only maintain the original attitude for a short time, unable to continue the movement according to the operator's wishes.

Generally speaking, there are about two or three commonly used frequency bands in the wireless data link of consumer low and slow small uav, which are 2.4GHZ, 5.8 GHZ and 915MHZ respectively. These three bands are often the main frequency bands of illegal consumer uav. For professional uavs, China's ministry of industry and information technology stipulates 845MHZ and 1.4ghz as the professional frequency bands of uav data link. In general, because the professional of unmanned aerial vehicle (uav) is often a government department in China and even the law enforcement departments use, in the tightly controlled state, the illegal use of the probability is very low, plus the two special frequency band wireless data link product yield is low and the price is high, the average consumer unmanned aerial vehicle (uav) rarely used the two frequencies, so that the general counter jammer mainly concentrated in the 2.4 GHZ, 915 MHZ and 5.8 GHZ three frequency bands.

In addition to the wireless data link, uav also has an important frequency point, is used for navigation "satellite navigation signal frequency point"! At present, there are three kinds of satellite navigation systems commonly used for uav, namely the GPS of the United States, the GLONASS of Russia and the BD of China. Most of today's satellite navigation chips are compatible with these three systems, and the mainstream chip technology USES the fusion algorithm of two or all three of these systems.