With the rapid development of UAV technology, the UAV market is emerging and expanding, and UAV has achieved vigorous development in the civil field. In the civilian field, drones have played an important role in agriculture, forestry and plant protection, rescue and disaster relief, logistics and transportation, security and inspection. At the same time, the threats and risks of drones have gradually emerged.

　　Uav defense systems in key areas such as nuclear power plants and oil fields need to be built. What is anti-drone technology? Anti-uav technology refers to the means or measures that can detect and disable UAVs, mainly by integrating or improving existing advanced technologies to detect, track, identify, interfere with, trap, control or destroy UAV targets.

　　In general, anti-drone is a complex system engineering, generally implemented in two steps: accurate detection, tracking and identification of drones; According to the actual situation, the UAV is counterattacked to achieve the effect of forcing it to land, return or destroy. What are the main anti-drone technologies? Anti-drone technology can be roughly divided into two categories according to its functions: one is drone detection technology, and the other is drone countermeasures technology.

　　Drone detection technology First let's talk about drone detection technology. Uav detection technology is the comprehensive use of various sensors to "discover" or "find" the threat target, the use of the target UAV physical properties (such as optical characteristics, thermal characteristics, acoustic characteristics, magnetic characteristics), through the measurement of some of the above characteristics to find the target UAV and identify.

　　Radar detection: The radar system detects and measures the position of the drone by transmitting electromagnetic waves and using the electromagnetic wave reflection principle of the drone body. By receiving and analyzing the reflected radar waves, information about the drone target can be obtained.

　　Radar has the advantages of long detection range, accurate positioning, fast reaction speed, less influence by weather and high technical maturity.

　　When the detectability of UAV is in line with the resolution of radar, the radar can achieve very good reconnaissance and detection effect. However, radar detection technology has a close blind area in the process of use, and radar detection technology is difficult to detect UAV targets made of non-conducting materials such as plastic or metal materials with wave transmission. When the drone is hovering or moving slowly, the radar is also difficult to detect the drone target due to the low Doppler shift.

　　Radio spectrum detection: In general, during the flight of the UAV, the internal flight control system and the map transmission system will send out radio signals. Radio spectrum detection is to achieve accurate positioning of the target UAV by monitoring the control and signal transmission without encryption processing.

　　Compared with radar detection technology, radio spectrum detection equipment is cheaper and can meet a wide range of defense needs. However, the radio spectrum detection technology takes a lot of time to crack the encrypted signal, which is not conducive to improving the tracking efficiency. And if the drone is in an autonomous cruise state or silently sailing without transmitting signals, the radio spectrum detection technology will not work.

　　Photoelectric detection: photoelectric detection equipment can use different bands to achieve the acquisition of target UAV images, common bands in addition to visible light band, infrared band, as well as thermal infrared, laser infrared and so on. The analysis and processing of these waveband images can detect, identify and track the UAV target, and obtain its type and location information. Photoelectric detection has two main types of technology: visible light detection and infrared detection. Visible light detection is the use of various imaging equipment working in the visible band to detect the video image of the target UAV, so as to identify and confirm the target, and track the target. The technology is suitable for use during the day, its equipment cost is low, the related technology is more mature, and the application is more common.

　　The detection effect of visible light is greatly affected by the weather, and the detection effect is poor when the visibility is low.

　　Infrared detection is to use the infrared radiation difference between the background and the UAV target to monitor the target, first obtain the target and its background image, and then detect, identify and track the target through a series of image processing technologies.

　　In fact, all objects with temperatures higher than absolute zero are radiating infrared rays, and drones generate heat from batteries and electric motors during flight, providing opportunities for the application of infrared detection technology.

　　Infrared detection is susceptible to various heat sources and sunlight interference, and is more suitable for night use. When the distance of the UAV is relatively far, the pixels it occupies in the detection image are particularly small, and it is difficult to distinguish the UAV pixels from the noise points, so it is difficult to effectively balance the missed detection rate and the false alarm rate in the actual detection. In addition, compared with visible light detection equipment, infrared detection equipment cost is high, its application is limited to a certain extent.

　　However, each technical means has its shortcomings, and the effect of using any detection technology alone is limited. In order to improve the detection capability, two or more technologies can be integrated for joint detection. At present, there are some products or systems that integrate multiple detection technologies.