| In recent years,with the development of unmanned aerial vehicle(UAV)technology,UAV have been widely used in the civilian field.While bringing convenience to daily lives,due to the lack of relevant laws and regulations,there are also many potential safety hazards.In particular,the frequent occurrence of UAV black-fly incidents has seriously threatened public safety.Effective supervision of UAV flight is imminent.The supervision of UAV based on rapid discovery and accurate identification of UAV targets.The passive direction method has the advantages of strong anti-interference ability,long working distance and wide frequency coverage,and is suitable for the detection of the target of the UAV.Because the positioning of the target of the drone is based on the signal detection of the UAV.First,this thesis analyzes the characteristics of UAV signals.The communication system and working frequency band of common UAVs are discussed.The frequency and time domain analysis of the measured UAV remote control and image transmission signals are carried out,and the characteristics of signal bandwidth and center frequency are understood.Combining the specific signal characteristics and engineering practical considerations,the amplitude-comparison method of passive positioning is used to measure the target of the UAV.The basic principle of the direction-finding method and the source of error are analyzed,and the error simulation analysis is carried out on the main factors causing the error.Then consider the problem of inordinate values in the measurement data that may appear in the actual direction finding process.The three inordinate values processing methods of Grubbs criterion,Schauville criterion and Laida criterion are discussed and the comparison of each criterion is analyzed.Finally,the Grubbs criterion was selected to discriminate the possible inordinate values in the direction finding data,and combined with the direction data of the UAV collected in the actual test,the simulation analysis was carried out.In order to realize the rapid discovery and accurate direction of the UAV target,it lays a solid foundation for the UAV counter.This thesis proposes a passive direction finding software for UAVs that combines with the direction-finding system.The software can display the direction finding results in the map in an intuitive and clear manner in the first time,which is convenient for determining the direction of the drone and counter-measuring it in time to ensure the safety of the airspace.It is also possible to store the direction finding data and generate a flight record for the user to view.The feasibility and requirements of the software are analyzed in combination with the actual project,and the overall system architecture of the software and the design scheme of each module are expounded.In the Visual Studio development environment,the development of passive direction finding software communication module,UAV detection and display module,and UAV flight log module was completed,and the corresponding functions were realized and the result was given. |
