In recent years, with the gradual opening of low-altitude airspace control and the rapid popularization of DRONE (UAVS) products, there have been more and more incidents of "low, slow and small" targets such as DRONE (UAVS)s flying illegally, disrupting normal aviation order, espionage investigations, and terrorist attacks. Serious security risks have affected national security and the normal development of the national economy. "Low, slow and small" targets refer to flying objects with low flying altitude, slow flying speed and small radar reflection area. The typical types are drones and birds. Low-slow and small targets have a low flight altitude, and the low-altitude area has many occlusions and complex environmental clutter; the flight speed is slow, and the Doppler frequency is not obvious; the RCS is small, the reflected echo intensity is small, and it is easy to be submerged in noise and environmental clutter. middle. Therefore, low-slow and small targets can flexibly achieve low-altitude and ultra-low-altitude raids, and have the characteristics of "difficult to detect, difficult to control, and difficult to handle".