The Study On Applications About High-speed Railway Precision Control Network Retest Based On GPS

As a major achievement of railway science and technology, Modern high-speedrailway has injected new vitality into China's railway transport and represented thedevelopment direction of transportation and railway construction. The vitality ofhigh-speed railway is reflected in its high speed, high density, high comfort and highsafety. To achieve high-speed, comfort and security, we need smooth and stable highlinewhich requires strict control of the line structure of various types of distortionerror. In the pre-laying track ballastless, deformation of line construction and all kindsof measurement errors must meet the design specification requirements.High-precision measurement outcomes are an important quality assurance ofhigh-speed railway construction.High-speed railway from the survey design, construction and operation tomaintenance will go through a long period of time. By the impact of externalconditions, will result in the movement at all levels of the control points, and then willbe affected in varying degrees to the line construction and operation of engineering onMaintenance observations.The main research productions are listed below:(1) The characteristic of High-speed railway measurement is like of ribbon, theconstruction was done in one or several strips. For the high precision control ofHigh-speed rail network, some provisions in specifications for survey engineering ofHigh-speed railway clearly states: horizontal control network of high speed railproject measurement should use independent system. The system coordinate length ofdeformation should not be greater than 10mm/km in the corresponding designedelevation surface.The use of national unity 3°or 6°Gaussian plane rectangularcoordinate system mostly cannot meet those requirements after two imputed inHigh-speed railway network for the project and the retest. In order to ensure projectquality and accuracy of measurement, we can choose a suitable reference surface or using any of independent Gaussian coordinate projection plane rectangular coordinatesystem to reduce the projection distortion;(2) How to choose a high-level control points as the initial data will directlyaffect the overall accuracy of the retest control network and the retest of the originalsurvey grid network and the results of comparative analysis, thereby affect the entireretest stability analysis of control points. Paper uses five different methods such as theunit weight variance hypothesis testing, the comparison method of actual baseline,constraint adjustment method (direct analytic method of adjustment result)andannexed traverse coordinate misclosure testing method to analyses the stability of theknown high-level control points in retest control network and determines the referencepoint (starting point) compatibility.(3) Access to retest results, the author should analyses the retest and the originaltest results and compare two or more the difference between the plane rectangularcoordinates and establish a reasonable mathematical model of a data processing toevaluate the stability of the control points by means of the significance test of optimalmethod to estimate displacement and mark stone appearance in the view field.