Research And Application Of Connection On Ellipsoid With Normal Section As The Central Meridian

With the rapid development of the national economy,the comprehensive development of the high-speed railway business,the continuous increase in operating speed,and the continuous improvement in comfort,it has put forward higher requirements for surveying work.In order to meet the requirements of the projected length distortion of not more than 10 mm / km in the "High-Speed Railway Engineering Survey Specifications",it is necessary to divide the highspeed railway line into multiple sections and establish their own normal cross-section meridian ellipsoid Gaussian projection.The connection of the meridian ellipsoids of adjacent normal sections has the problems of inconsistent intersection points and deformation of the connection angle.If not handled properly,it will bring great inconvenience to the survey design,construction and operation.Based on the above problems,the background and significance of the connection of adjacent projection bands of Gaussian projection are firstly studied.The main error sources of Gaussian projection length distortion are elevation normalization correction and Gaussian projection distortion,and the solution is studied in detail.The forward and inverse algorithms of Gaussian projection are described,and the ellipsoid expansion method,ellipsoid translation method and ellipsoid deformation method are briefly described.The image clearly describes the ellipsoid transformation process,which lays the foundation for further research.Secondly,the ellipsoidal Gauss projection theory of meridian with normal cross section is studied in depth.Through the study of the theoretical space coordinate transformation process of the normal section meridian ellipsoid,the construction of the normal section meridian ellipsoid,and the transformation of the normal section meridian ellipsoid,the length deformation caused by the normalization correction of elevation and the Gaussian projection deformation are reduced,and Applied to the engineering example,it fully reflects the unique superiority.Thirdly,the convergence theory of meridian ellipsoids with different normal sections is mainly studied.Firstly,the basis of line segmentation was effectively determined using the least squares method,and the problem of inconsistent correspondence between the intersection points when the meridians of normal sections were found was found.A solution to the problem of normalization of the intersection normal points was proposed.Aiming at the problem of angular deformation in the conversion of the meridian ellipsoid of normal cross section adjacent to the adjacent zone,detailed analysis and research were carried out in terms of latitude,connection line length,connection line angle,projection zone width,and projection plane height,and the adjacent zone was determined.The relationship between the angular deformation and its corresponding in the conversion determines the theoretical basis for the connection of the ellipsoids of the meridians of different normal sections,which realizes the seamless connection of the road and improves the smoothness of the road.Finally,the meridian of different normal cross sections with normalized intersection normal is applied to the engineering example.Through analysis of the solution data,the problems of non-overlapping intersections and excessive length deformation can be solved.Through the calculation of the angular deformation in the conversion of adjacent bands during connection,it meets the requirement of angular deformation of 0.5 ?,which solves the problem of “wearing sleeves” or generating corners when connecting lines.