Some Technique Questions Study About High-speed Railway Surveying

The optimal layout of High-Speed Railway control network is analyzed according to the precise requirement of the smoothness of the railway orbits for the orbits network. And the principle of the layout is analyzed in-depth. The viewpoint is presented taking the backbone control network as the reference control network of the whole railway based on the Three-Level network. The limitation of the application of the Gauss Projection in the High-Speed Railway measurement is researched. The projection that first sphere projection then Oblique Mercator Projection along railways is presented to the problem that the control area of Gauss Projection in the High-Speed Railway measurement is small, and it's feasibility is analyzed. And the experiment using the projection in the project of LuoFu Railway is made, and it is proved that his projection is much better than the Gauss Projection now used by the constructing enterprises. The plane data procession and the 3-D data processing model of the High-Speed Railways CPIII control network are analyzed, and the feasibility is analyzed using trigonometric measurement instead of precise leveling in CPIII control network elevation survey. It is proved according to the analyzing and calculating sampling the experiment data that the trigonometric measurement instead of precise leveling used in CPIII control network elevation survey can satisfy the required precision of the railway orbits. The suggestion is presented according to the calculating experiment that the treat with elevation and flat data apart instead of using three-dimensional network adjustment of direct observations in the CPIII data processing.