A brief discussion on “UAV detection technology”
2024-03-04
Today we will talk about drone detection technology.
UAV detection technology comprehensively uses various sensors to “discover” or “find” threat targets, taking advantage of the differences in the physical properties of the target UAV (such as optical properties, thermal properties, acoustic properties, and magnetic properties). Through the above Measurement of certain characteristics to find and identify the target UAV.
Currently, common drone detection methods mainly include radar detection, radio spectrum detection, photoelectric detection, and acoustic wave detection. Each of these detection methods has its own characteristics and applicable scenarios.
1. Radar detection
Radar detection is a radar system that emits electromagnetic waves and uses the principle of electromagnetic wave reflection by the drone body to detect and measure the position of the drone. Information about UAV targets can be obtained by receiving and analyzing reflected radar waves.
Radar has the advantages of long detection range, more accurate positioning, fast response speed, less affected by weather, and high technological maturity.
When the detectability of the UAV meets the resolution of the radar, very good reconnaissance detection results can be achieved using radar. However, there are short-range blind spots in the use of radar detection technology, and it is difficult for radar detection technology to detect UAV targets made of non-conductive materials such as plastic or wave-permeable metal materials.
When a drone is hovering or moving slowly, it is also difficult for the radar to detect the drone target due to the low Doppler frequency shift.
2. Radio spectrum detection
Generally speaking, during the flight of a drone, both the internal flight control system and the image transmission system will emit radio signals. Radio spectrum detection is to achieve precise positioning of target drones by monitoring unencrypted control and image transmission signals.
Compared with radar detection technology, radio spectrum detection equipment is cheaper and can meet a wide range of defense needs. However, radio spectrum detection technology takes a lot of time to crack encrypted signals, which is not conducive to improving tracking efficiency.
And if the drone is cruising autonomously or sailing silently without emitting signals, radio spectrum detection technology will not work.
3. Photoelectric detection
Photoelectric detection equipment can use different wavebands to collect target drone images. In addition to visible light bands and infrared bands, common wavebands also include thermal infrared, laser infrared, etc.
Analysis and processing of images in these bands can detect, identify and track UAV targets, and obtain information such as their type and location.
There are two main types of photoelectric detection technologies: visible light detection and infrared detection.
Visible light detection uses various imaging devices working in the visible light band to detect video images of target drones, thereby identifying and confirming the target and tracking the target. This technology is suitable for use during the day, its equipment cost is low, the related technology is relatively mature, and its application is relatively common. The detection effect of visible light is greatly affected by weather, and the detection effect is poor when visibility is low.
Infrared detection uses the infrared radiation difference between the background and the UAV target for target monitoring. It first obtains the target and its background image, and then detects, identifies and tracks the target through a series of image processing technologies. In fact, all objects with a temperature higher than absolute zero radiate infrared rays. During the flight of the drone, the battery and motor will generate heat, providing opportunities for the application of infrared detection technology.
Infrared detection is susceptible to interference from various heat sources and sunlight, and is more suitable for use at night. When the drone is far away, it occupies very few pixels in the detection image, and it is difficult to distinguish the drone pixels from noise points. Therefore, in actual detection, it is difficult to effectively balance the missed detection rate and false detection rate. Police rate. In addition, compared with visible light detection equipment, the cost of infrared detection equipment is high, and its application is limited to a certain extent.
4. Acoustic detection
During navigation, the drone’s power unit and propeller blades will emit sound waves. These sound waves can be regarded as the “audio fingerprint” of the target drone. Each drone has its own unique acoustic characteristics.
Acoustic wave detection mainly identifies the information of the target drone by collecting sound signals and comparing them with the acoustic characteristics of the drone in the database. Acoustic detection only passively receives acoustic signals in the air and is not easily detected by drones, so it is safe and low-cost.
However, acoustic detection technology cannot meet the requirements of long-distance target drone detection, and its applicable scenarios are limited to low-noise environments.
According to an analysis by the UAV Research Center of Bard College in the United States, radio spectrum detection technology and radar detection technology are used the most, followed by photoelectric detection technology based on visible light or infrared, and acoustic wave detection technology is the least used.
However, each technical means has its shortcomings, and the effects achieved by using any detection technology alone are limited. In order to improve detection capabilities, two or more technologies can be integrated for joint detection. Currently, there are already some products or systems that integrate multiple detection technologies.
For example, the two anti-UAV systems “UAV Guard” and “UAV Dome” launched by Israel both integrate photoelectric sensors, detection radars, and special electronic attack systems to detect small UAVs. , identification, and interference.