Research Of Active And Passive Integrated UAV Detection Technology

The civil market of UAV has developed rapidly in recent years,but the security problems caused by the abuse of UAV have also increased year by year,and the development of UAV detection and supervision technology is relatively lagging behind.A single detection technology for UAVs is often limited,and a composite detection technology that uses multiple detection methods to complement each other is being promoted.Active detection and passive detection have a high similarity in hardware structure,combining the advantages of the two detection technologies is conducive to improving the detection efficiency of UAVs.This thesis studies the active and passive integrated UAV detection technology,and the main contents are as follows:(1)The similarities and differences between active radar detection and passive detection are studied,and a system scheme for active and passive detection of UAV is proposed.Phased array is shared through time division multiplexing,and the working mode of active and passive collaborative search is designed.(2)The beamforming algorithm of radar detection mode and reconnaissance mode when phased-array antenna is shared is studied.In radar detection,a narrow beam with equal sidelobe is formed by weighted window function.A beam width of 120° is formed by genetic algorithm or convex optimization,and the main lobe is approximately Gaussian type.The direction finding method of radar and reconnaissance is studied,and the error of narrow and wide beam direction finding is analyzed.The indicated search process guided by reconnaissance information is studied.The indicated search strategy based on maximum information gain is used.The simulation results show that,compared with the traditional sequential search under the same conditions,the detection probability is increased by about 26%,the search time is saved by about 59%,and the search efficiency is improved.(3)The method of UAV signal reconnaissance is studied,including the detection and identification of remote control signal and picture signal.Remote signals are frequencyhopping signals.The signal characteristics under the time-frequency graph are studied,and the frequency-hopping period is estimated based on the time-frequency ridge.This method removes the interference signals from the spectral characteristics and avoids the interference of other frequency-hopping signals.The detection method of graph transmission signal is studied.The modulation mode is detected by the characteristic of high order cumulant,and the graph transmission signal is identified from the bandwidth feature on the smoothed power spectrum.(4)The detection process of UAV target by radar under the pulse Doppler radar system is studied,and the process of radar signal processing and data processing is simulated.The position and velocity information of target is correctly extracted from the echo,and the target track is finally formed.Finally,the process of active and passive detection is simulated to verify the feasibility of the scheme.