| In the exploration tasks such as river survey,hydrographic survey and seafloor topography survey,basically,a single multibeam bathymetric system is carried or towed by a surface vessel for measurement,and this traditional way is not only time-consuming and labor-intensive,but also cannot fully exploit the advantages of multibeam bathymetric system.The USV(Unmanned Surface Vessel)can navigate and measure the seafloor topography of designated rivers,sea lanes or offshore areas autonomously,so the disadvantages of traditional measurement methods can be effectively avoided by carrying multibeam bathymetry system by USV.Thesis starts from the composition and working principle of dual multibeam bathymetry system,designs the connection method between multibeam and USV,and verifies its measurement performance through real sea test,the main work is as follows:1.Combining the existing USV and MS8200 multibeam bathymetry system in the laboratory,based on the hull structure and the composition and principle of multibeam bathymetry system,design a system of USV carrying multibeam bathymetry equipment,and divide the system into upper computer subsystem,USV subsystem and measurement subsystem.In addition,according to the installation requirements of multibeam bathymetry equipment,design the installation bracket,and through software coordinate conversion,make the sonar probe of multibeam and ship hull closely integrated in hardware and software to ensure the safety and reliability of the system.2.The relationship between multibeam measurement and route tracking is analyzed,and the corresponding research on the path tracking and control of USV is conducted for the problem of stability and accuracy of USV carrying multibeam equipment for measurement tasks.Firstly,based on the characteristics of USV moving on the water surface,the motion coordinate system of USV and its coordinate system conversion are established,and the mathematical model of USV is built.Then a set of control power system is designed on the basis of this model.The system is used to adjust the whole route for real-time tracking.The feasibility of the algorithm is verified through simulation.Meanwhile,during the sea test,the amount of deviation between the actual course and the target course is calculated through the autonomous cruise test,i.e.setting the course,sensing the positioning and heading declination situation through position and attitude sensors,conducting algorithm analysis and processing,and controlling the navigation condition of the vessel in the water,and the test results are the maximum value of the trajectory error of 19.22 meters and the mean value of the error of 2.89 meters;3.Thesis analyzes the working principle of multibeam bathymetry system,measurement method and multibeam measurement data processing method,in addition,it also analyzes the error composition and influence principle of multibeam bathymetry system,and analyzes and corrects the installation deviation,attitude deviation and sound velocity deviation that exist when it is mounted on the USV for undersea topography measurement,including ship attitude analysis and deviation calibration,sound velocity correction and water level correction accordingly..The system accuracy evaluation methods of relative and absolute accuracy of the multibeam bathymetry system are also discussed.Using two sets of MS8200 multibeam bathymetric system,the multibeam dual-probe experiment is conducted at sea,and the measurement data are analyzed for depth limit error,internal and external conformity comparison,and the bathymetric performance such as relative accuracy,absolute accuracy and beam quality of the multibeam bathymetric system to be evaluated is launched for comprehensive evaluation through error statistical analysis,and a set of evaluation methods is formed,and the results prove that the USV carrying multibeam dual-probe for undersea The result proves that the scheme of multi-beam dual probes on board the unmanned vessel for seafloor topographic survey is indeed feasible. |
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