Research On Key Technologies Of UAV Airborne Lidar Scanning System Based On Direct Geo-Referencing

Light Detection And Ranging(LiDAR)is a new type of earth observation technology developed gradually at the end of the 20 th century.Due to its high precision,efficiency,strong anti-interference ability and short operating cycle,it is widely used in Urban 3D Modeling,Geological Exploration,Power Line Inspection,Unmanned vehicle.After more than half a century of development,developed countries such as Europe and the United States have made relatively perfect progress in the hardware integration and software post-processing of LiDAR system,and have developed a variety of commercial airborne LiDAR systems.Due to the late start of research and the backward development of related hardware,the development of domestic airborne LiDAR system still lags far behind the international level.Therefore,it is urgent to strengthen the research on key technologies related to LiDAR system and develop a LiDAR system with independent intellectual property rights.In this thesis,the key technologies of the airborne LiDAR system,such as its composition,positioning principle,data decoding and error checking,are studied in theoretically and practically.The details are as follows:1.Analyzed the composition of the airborne LiDAR system and the time synchronization scheme of each subsystem.The positioning model of the airborne LiDAR system is deduced in detail,and the laser point cloud interpolation calculation software is written.2.The laser raw data decoding program was written with reference to the domestic laser scanning system data format,and analyzed the data processing flow of the system.For the direct geographic reference of the system,the differential positioning model and the DGNSS/INS loose combination scheme were analyzed,and the measured data was analyzed.Verify the solution.3.Discussed the various error sources of the airborne LiDAR system in detail,qualitatively analyzed the influence of the placement error angle on the system,and compared the two common calibration schemes: Geometric Distribution Method(Manual Inspection Method)and The known ground control point calibration scheme.Aiming at the positioning error angle of the system,a Calibration Method of LiDAR Without Control Points is proposed,and the feasibility of the method is verified by the measured data.4.Finally,designed the field scanning experiment of UAV-borne LiDAR system.Through collecting the raw data of laser scanner,GNSS data and IMU data,data decoding,POS calculation and point cloud interpolation calculation are carried out respectively.The results are displayed and analyzed by MicroStation.