Research On Target Detection And Recognition Technology Of Rotor UAV

The application of various types of UAV brings great convenience to people’s lives.At the same time,it has also posed a huge threat to the safety of airspace.How to effectively monitor such aircraft has become a new challenge.Because the UAV belong to the type of "low-altitude small slow-speed" aircraft,it has the characteristics of low flying height,small physical volume,and slow flying speed,besides the clutter background in its airspace is complex,so the UAV target has low SNR,and a large number of interference targets in the radar detection range.Traditional detection method is difficult to detect it effectively.The difficulty of UAV target detection is how to reduce false alarms as much as possible while effectively detecting the target,and how to improve target detection and recognition performance under low SNR conditions.This article does the following research work on the above problems:(1)Introduces the common method of "low-altitude small slow-speed" target detection in engineering with LFMCW radar.(2)In order to solve the problem of false alarm caused by a large number of ground moving targets or other interfering targets in the detection range and the complex clutter background in the detection process of the rotor UAV target.This paper proposes a detection method for rotor UAV based on target Doppler frequency band broadening.Using the rotation characteristics of the rotor during the flight of the rotor UAV,its radar echo has a certain Doppler band broadening in the frequency domain,combined with the adaptive CFAR algorithm,effectively filtering the interference target,greatly reducing the false alarm rate of target detection.(3)In order to solve the problem of low detection rate caused by the low SNR of the target echo when detecting the target of the rotor UAV.This paper proposes a method of multi-rotor UAV echo accumulation based on correlation detection.First,mathematical modeling of the UAV rotor echo,through the priori UAV flight parameters,the rotor echo signal in an ideal state is obtained.Then detect UAV target by correlation detection methods under low SNR.Based on the correlation detection results,the main lobes of each rotor echo are accumulated to improve the echo’s SNR.The echo signals after accumulating improve the performance of target recognition by time-frequency analysis.