Research On Measurement Error Analysis Of Laser Tracker And Coordinate Transformation And Fusion Method Of Multi-Stations

In the field of large-scale space coordinate measurement,coordinate measurement is one of the key technologies due to the problems of large measurement space,complex structure,high accuracy requirements,and complex site environment.The analysis and expression of point error is related to whether the measurement result is The important indicators that meet the requirements,the emergence of laser trackers provide a new solution for coordinate measurement.In this paper,starting from the principle of the laser tracker measurement system,the spatial point error is expressed as the main line,and the distribution rule of the spatial point error is analyzed by numerical simulation,and the spatial point error ellipsoid model is constructed.The covariance matrix is used to evaluate the uncertainty of the transfer error,and the error ellipsoid is used to visualize the uncertainty.It is verified through experiments that the data fusion algorithm based on error ellipsoid can improve the accuracy of measurement data of multiple stations,and realize large-scale,high-precision and high-efficiency large-scale space measurement.The research content of the thesis is as follows:(1)This paper introduces the measurement principle and error source of laser tracker,analyzes the factors affecting the point accuracy from the angle measurement and distance measurement of laser tracker,and designs relevant experiments to verify that the measurement accuracy in practical application is lower than the nominal accuracy.(2)For the analysis and expression of space point measurement accuracy,the technical advantages of mathematical analysis method,mathematical statistics method and error ellipsoid method are systematically discussed to provide theoretical basis for error analysis of large-scale coordinate measurement.The factors affecting the measurement accuracy are simulated and analyzed with MATLAB software,and the visualization of error ellipsoid at any spatial point is realized.(3)Transfer station error distribution model is constructed.Transfer station error parameters and coordinate transformation uncertainty are expressed by covariance matrix,and the accuracy of transfer station is visualized by error ellipsoid.Based on the sensitivity coefficient,the influence laws of different spatial layouts of common points on conversion accuracy are analyzed to provide reference for layout optimization of common points in large-scale coordinate measurement.(4)The factors affecting the accuracy of transfer station are discussed.Taking the sensitivity coefficient of the error of transfer station parameters as the evaluation standard,the rules affecting the accuracy of common points are analyzed in detail from the number of common points,the layout of common points and the envelope.Based on the error ellipsoid theory,the weights are determined according to the size and shape of the error ellipsoid.The weighted fusion algorithm is used to realize the integration of measurement data from multiple stations.The simulation analysis and engineering case verify that the accuracy of the fused measurement data is significantly improved.