Application Research Of Laser SLAM In Small Waters Measurement

The accurate mapping of small waters is the basis of the fields of property rights investigation,water conservancy information construction and water area monitoring and control.However,the traditional measurement schemes such as GPS measurement and total station measurement cannot effectively solve the mapping problem of small waters,being characterized by irregular shape and complex surrounding environment.Therefore,this paper conducts research on small waters boundary positioning and 3D reconstruction,using the method of combining field surveying and data processing.The field surveying is completed with unmanned ship,and the data processing is used to solve the problem of small waters boundary positioning and 3D reconstruction by introducing laser SLAM.The main research work of this paper includes the following aspects:(1)The SINS/GPS combined measurement technology is used to assist the laser SLAM when the GPS signal is valid.On the one hand,Simulation analysis of initial alignment of the strapdown inertial measurement system is carried out based on Kalman filtering algorithm,on the other hand,Simulation analysis of in-motion alignment is carried out in order to improve the estimation accuracy of the deviation angle and the gyroscope bias,which can determine the ship maneuvering scheme suitable for small waters measurement.(2)In view of the specific environment of small waters,the estimation accuracy of three typical 3D laser scanning matching algorithms is simulated and compared,and the PPICP algorithm is used to build the front-end module.In view of the characteristics of small waters,such as the scanning points of remote scene are more scattered and rarely represent surface features,the improved PPICP algorithm is proposed,and the improved strategy can effectively reduce the probability of matching failure.(3)In view of the situation that the pose graph has few constraints and the laser scanning matching error rate increases sharply when extreme situations occur,the combined measurement system is added as priori observation of pose nodes on the basis of the conventional pose graph framework,which can improve the system robustness.In view of the characteristics of point clouds in small waters,the improved preprocessing technology for point clouds is proposed,which can effectively eliminate non-waterfront information.finally,the three-dimensional point cloud map of small waters is constructed by point clouds registration,and the waters boundary is extracted by building occupancy grids.On the basis of the above research,the unmanned ship equipped with LIDAR,IMU and GPS is used as the data acquisition platform,and the laser SLAM measurement scheme proposed in this paper is used as the internal data processing unit.The experimental result reveals the effectiveness and feasibility of the laser SLAM scheme in this paper by measuring the selected small waters.