Analysis Of Reflection Characteristics And Detection Algorithm Of Rotary-Wing UAV

With the rapid development of rotary-wing UAV,it has been widely used in various industries,as well as national defense and civilian fields.It plays an important role in public safety,live TV broadcasting,power inspection,agricultural production,etc.At the same time,the rotary wing drone is a kind of low-speed and small equipment,and it is simple and convenient to use.Flying at low altitudes or sensitive special areas in cities poses serious safety hazards,so a method is needed to monitor its flight.Therefore,studying the reflection and detection of rotary-wing UAV has important research significance.Under the premise that optical inspection is difficult to adapt to changing weather and dark night,thermodynamic inspection is expensive.This thesis proposes a method of using mobile communication base stations in cities as radiation sources to detect rotary-wing UAV.Only need to design the receiver according to the characteristics of the communication signal and the actual conditions,which is more flexible and convenient.Because 4G base stations are widely distributed in cities,the signals sent by them are radiated into the atmosphere indiscriminately,and detection can be achieved by receiving signals with receivers in areas that need to be detected.In the future,4G will be well compatible with 5G systems.Therefore,4G signals are the preferred signals among civil radiation sources and can be used to realize the detection of rotary-wing UAV.Before using mobile communication signals to detect UAVs,the study of the reflection of the communication signals on the rotary-wing UAV is to lay the theoretical foundation for subsequent detection and specific implementation.The shape of the usual rotor drone is irregular,and it is difficult to analyze it.Using the method of model fitting,the irregular rotor drone is decomposed into two parts: a regular cube and a rotor for analysis.By analyzing the reflection of the communication signal irradiated to the two parts,and fitting the two parts,the expression of the reflected signal of the fitted rotor UAV is obtained.Then simulate and analyze the characteristics of the reflected signal under different reflection coefficients and different incident angles,and obtain the change law of the communication signal illuminating the rotary-wing UAV under different angles.At the same time,according to the requirements of actual detection system design,a leading edge sliding window detection algorithm based on environmental perception is proposed.Combined with the idea of constant false alarm detection algorithm,the mean value and ordered statistics detection algorithms are improved,the leading sliding window is retained,and the trailing sliding window of the detection unit is removed.Use a known sequence to estimate the power of the background clutter in advance to make up for the inaccurate estimation of the background clutter power using only the leading-edge sliding window.At the same time,it can further reduce the false alarm rate,and only half-window detection can achieve real-time detection and Solve the problem that the target at the end of the sequence cannot be detected.Finally,the improved algorithm is simulated and analyzed,and the detection diagram of the new algorithm and the performance comparison chart with other algorithms are given to verify the effectiveness of the proposed algorithm.Finally,based on the above theoretical analysis and algorithm research,based on hardware radio frequency equipment and software design,the UAV detection system is built.The transmitter simulates the base station to send signals,and the receiver detects the monitoring airspace.The experiment verifies that the system can detect the rotary-wing UAV,and tests the detection effect and system performance under different targets.