There are many difficulties in the detection of small and micro unmanned aerial vehicles, mainly including the following aspects:
The characteristics of the target make detection difficult.
Small radar reflection cross-sectional area: Small and micro unmanned aerial vehicles (UAVs) are compact in size, and their radar reflection cross-sectional area is much smaller than that of large aircraft. This results in relatively weak reflected signals received by the radar, shortening the detection range of the radar and making it difficult to detect targets from a greater distance.
Low flight altitude: Small and micro drones such as multi-rotor drones are typical "low, slow and small" targets. Their flight altitude is low, and they are in the blind spot of traditional air detection radars, making them easily masked by ground clutter.
Slow flight speed and strong maneuverability: Small and micro unmanned aerial vehicles (UAVs) have a slow flight speed and their movements are unpredictable. They can also perform rapid maneuvering flights, changing their flight direction and speed at any time, and even hover and move vertically. This brings great difficulties to the automatic tracking algorithm of radar, making it hard for them to stably track and lock onto targets.
Interference in complex environments
Ground noise interference: When small and micro drones fly at low altitudes, they are subject to noise interference generated by ground buildings, mountains, forests, etc. These noises will mix with the echo signals of the drones, increasing the difficulty of distinguishing the drone signals from the echoes.
Electromagnetic interference: There are a large number of electromagnetic interference sources in environments such as cities, mountainous areas or the ocean, such as communication antennas, two-way radios, telemetry systems, etc. These interferences can interfere with the signal reception and processing of detection equipment such as radars, affecting the detection effect.
Limitations of detection technology
The shortcomings of a single detection method: Traditional air defense radars are designed for large aerial targets and have poor detection effects on small and micro unmanned aerial vehicles. Although there are targeted low-altitude detection radars, there are still some problems. For instance, X-band radars have good low-altitude propagation capabilities, but they suffer significant propagation losses in the atmosphere. Photoelectric detection technology is greatly affected by fog, water vapor, dust and other factors, with limited detection distance and a relatively high false alarm rate.
High false alarm rate: To enhance the detection capability of small and micro drones, it is usually necessary to increase the sensitivity of the radar. However, this will lead to an increase in the false alarm rate, causing the system to spend more time and resources distinguishing between real and false targets.
The difficulty of multi-target tracking: In modern battlefields or complex environments, multiple small and micro unmanned aerial vehicles (UAVs) may appear simultaneously, which poses very high requirements for the multi-target tracking and discrimination capabilities of detection systems such as radars. It is extremely difficult to accurately track and distinguish all targets while maintaining a low false alarm rate and missed alarm rate.
Challenges of special types of unmanned aerial vehicles (UAVs) : Some special types of small and micro UAVs, such as fiber-guided UAVs, have strong anti-interference capabilities due to their signal transmission running inside optical fibers and not radiating signals externally, making them difficult to be detected by conventional radio monitoring and other means.