| In recent years,lidar scanning technology has developed rapidly,it has become a routine measurement method to obtain texture and point cloud geometry information from lida.Compared with the conventional terrestrial lidar scanning,the mobile lidar scanning and measuring system is efficient and convenient.The conventional mobile lidar scanning system use global navigation satellite system and inertial navigation system combined navigation mode.Advent of simultaneous localization and mapping has overcome the limitations of traditional localization methods.Laser SLAM can realize localization without GNSS signal,which is complementary to GNSS/INS combined navigation mode.In urban surveys,there are many complex environments where vehicles are impassable.According to the above characteristics,this paper combines GNSS/INS navigation technology and laser SLAM technology,independent integration portable mobile measurement system,the calibration method based on the special target is used to correct the placement angle error of the system and improve the overall precision of the system.The main research contents and achievements of this paper include:(1)This paper introduces the research background and current situation of lidar measurement system in GNSS/INS navigation mode and laser SLAM technique.The advantages and disadvantages of combined navigation and laser SLAM localization technology are compared.(2)The hardware structure and integration principle of portable measurement system are described.The theoretical basis of GNSS/INS combined navigation mode(referred to as outdoor mode in this paper)and laser SLAM mode system is introduced respectively.(3)The error of portable mobile measurement system is analyzed,aiming at the placement angle error of the system,the calibration method based on the special target is adopted to calibrate the system,the experiment and precision analysis of the measurement system are carried out,the validity of the method is verified.(4)Wrote a set of portable mobile measurement system data acquisition and processing procedures,through the design of Beijing hutong three-dimensional point cloud collection experiment,verify the effectiveness of the combination of GNSS/INS navigation mode and laser SLAM localization mode.To sum up,in this paper,the theoretical basis of the integration and calibration of the portable mobile measurement system is studied,the error sources in the ensemble process are analyzed.Through the independent design of the calibration field and experimental program,the system high precision calibration algorithm is realized,the definite and conditioned accuracy of the measuring system is analyzed.Finally,data collection experiments are carried out on Beijing hutong,it is proved that the system can be used in many complex environments,it can efficiently collect point cloud data of complex environment,become assistance in actual work. |
