Radar Echoes Modeling Of The Multi-rotor UAV Utilizing Flight Control Characteristics

In recent years,the phenomenon of "illegal flight" caused by the low barriers to entry of UAVs has posed a potential threat to public security.Radar often needs more test data to detect and classify UAVs.However,it is not easy to obtain the practical measured data of various parameters and different motion states of the target that is convenient to control.Therefore,the radar echoes modeling of the multi-rotor UAV has become an important technical means to carry out radar detection and recognition research for multi-rotor UAVs.To address the problem that the existing radar echo modelling of the multi-rotor UAV does not fully reflect the motion characteristics of the UAV as the multi-rotor UAV’s body motion state is considered separately from the rotor rotation speed.In this thesis,a simplified motion model is given by utilizing the multi-rotor UAV’s flight control characteristics.The motion model can reflect the correlation between the degree of remote control lever and the multi-rotor UAV’s motion states such as the multi-rotor UAV’s body speed,attitude angle and each rotor rotation speed.The results of radar echo modeling of the multi-rotor UAV with high fidelity are obtained by combining the motion model with the radar echo signal model.And the results can provide a controllable data source for the research of UAVs radar surveillance and make up for the shortage of practical measured data.Firstly,according to the requirement of radar echo simulation and the flight control principle of the multi-rotor UAV,a simplified motion model combining the multi-rotor UAV’s body motion with rotor rotation speed is proposed.The calculation method of related parameters in the motion model is derived and given.Then the further simplified horizontal flight model and oblique flight model are given according to the actual flight situation.Secondly,based on the multi-rotor UAV single-frequency pulse echo signal model which is established by the scattering point integration algorithm,the multi-rotor UAV linear FM pulse radar echo model is derived and given in detail.Then the radar echo signal model is combined with the simplified motion model of the multi-rotor UAV by coordinate transformation.It is verified through experiments that for the case of the multi-rotor UAV with variable speed motion,the radar echo modeling needs to use the correlation between the multi-rotor UAV’s body speed and each rotor rotation speed to jointly consider the multi-rotor UAV’s motion state and the radar echo model.Thirdly,for the advanced phased array radar in the existing UAVs surveillance,based on the antenna pattern function of the uniform line array,the pattern function of the circular array is analyzed.Furthermore,the differences of amplitude and phase between different beams and the multi-rotor UAV’s motion model utilizing flight control characteristics are used to obtain the modeling results of different modes for phased array radar.Finally,a radar echo signal generation system of the multi-rotor UAV is designed.The radar echo signal of the multi-rotor UAV is generated by utilizing the above model,and its motion parameters,echo data and related characteristics are visualized.