Research On Several Problems For Precise Control Survey Of A Certain High-speed Railway Engineering

In order to change the railway business has stayed at a long-term and improves the stress status of railway transportation and substantial increases of passenger and cargo transport capacity,nowadays,our country attaches great importance to the development of high-speed railway.With the fast,fair prices features and high freight volume, it is also a important goal of development of high-speed railway is safety and comfort.The primary condition for High-speed train' s safety and comfort is high ride comfort orbit which depends on the track laying and maintenance of high-quality process,and needs the application of sophisticated measurement techniques.Because of the work of any kind of measurement will have errors,it must be taken to a certain measurement procedures and methods to prevent the accumulation of those errors.To solve this problem,we surveyed the general area before the establishment of control network,and measured detail points nearby from the beginning of each control point respectively in practical measurement.Therefore,in order to ensure safe and comfortable of high-speed railway operational,we need to set up a systematic,reasonable sophisticated control network and data-processing mode of operation for construction and maintenance of the latter railway line,is to provide protection to ensure orbit high ride comfort.With the information,standard and theoretical knowledge of high-speed railway' s precision control survey of high-speed railway and examples,this paper analysis and research on a number of issues of precision engineering of high-speed railway control network technical. In the process of high-speed railway' s construction,it is a premise of protect the construction to establish an effective,economical and practical sophisticated surveying control network,and operational maintenance of the accuracy of setting out.In this paper,by applying of precision engineering control measure and high-speed railway track technology,taking the existing norms and track indicators of comfort as a guide,and anglicizing of existing high-speed railway control surveying theory,first of all,with special treatment by use of LGO software to different level of high-speed railway original static GPS baseline data of a certain high-speed railway horizontal control network.And processing of the baseline calculation respectively and establishment of synchronous and asynchronous ring;Then by use of tgppsw software check the synchronous,asynchronous differential of closed loop and coordinate statistical under the different circumstances.After processing of unconstraint adjustment,and three-dimensional constrained adjustment by use of the corresponding benchmarks and the coordinate system.On this basis of which anglicizing and studying the accuracy of their corresponding indicators and research on the optimization of high-speed railway's control survey technology.At the same time,on the aspect of elevation control network,by discussing standard indicators of different grades levels,with NASEW software processing of second-class levels data of this section high-speed railway,then statistical analysis accuracy of the corresponding indicators.Combined with second-class levels data in conjunction the above measurement of high-speed railway adjustment of GPS coordinates coordinates,selected respectively with Polynomial surface function and mobile surface elevation model fitting,obtain elevation of corresponding plane point of known coordinates with interpolation,studying the accuracy of different elevation fitting models on the long-distance linear band region. The main conclusions are as follows:1.Actually,in the sophisticated control network survey of high-speed railway engineering,establishing a narrower bandwidth and independent Gaussian random projection plane right-angle coordinates should give sufficient consideration on the practical project,using appropriately the either changing the central meridian or ellipsoid expansion method or the both methods to achieve the target of the satisfaction of projection distort.2.With high precision and high efficiency and low-cost,GPS static relative positioning measurements is applied to establish control network can meet the requirement of sophisticated control network construction of high-speed railway by using proper optimize design and accurate and reliable method of data processing.From the perspective of the application,in this article by researching and anglicizing GPS network optimization and design and data processing theory and methods,presented sophisticated control network construction program of high-speed railway and technical standards and data-processing methods;3.Different adjustment methods,different coordinate frame of reference or different coordinate benchmarks usually were choosen by different construction units,when they carry on the process of constrained adjustment in the construction of sophisticated control network of high-speed railway.It will lead to some larger difference of ultimate baseline length and three-dimensional coordinates of the space.In order to ensure the unity of the base coordinates of control network,the base station network construction adjustment should be unified;4.It is suggested that data processing of CPI should build with both asynchronous ring and synchronization ring to ensure the reliability of the raw data.But for CPâ…¡and D-class networks data processing can be carried out only to build asynchronous ring as a check condition.As a result of various factors,the data may contain gross errors,although it passed the ring check,its reliability may be poor.Therefore,in order to obtain reliable data,error detection should be carried out on data which the number of observation satellite is fewer,for example:F test, W-Test test,etc;5.In the sophisticated control network measurement of high-speed railway,the relative difference of the adjustment results between CPâ… and CPâ…¡in the GPS 2000 and 2005 framework is almost fixed.This variation range of difference is only in 1mm.It shows that both coordinate frameworks all have highprecision.Therefore, in the conventional GPS surveying,both GPS 2000 and 2005 framework for the corresponding constraint adjustment of can meet engineering demands.But for the higher accuracy requirement of the high-speed railway' s control network,the best choice is the GPS 2005 coordinate reference framework which has higher resolution and accuracy;6.High-speed railway' s static GPS control network measurement is based on the three-dimensional adjustment mode,which fully takes into account of the concept of GPS baseline measurement correlation.The errors of instrument height measurement will be distributed corresponding in the progress of the baseline solution.In other words,the high measurement accuracy will also affect the accuracy of the baseline solution.In order to achieve the precision requirement,the instrument height measurement should be controlled in less than 1 cm in precision control measurement of high-speed railway.7.The number of the GPS observation satellite will be directly impact on the quality and reliability of GPS observation data. The more the number of observation satellites,the more redundant observation,the main on its accuracy and reliability will be enhanced;however,GPS data sometimes will include a number of bad satellite observation data.If they participate in GPS baseline solution,they will reduce the accuracy of observation. Therefore,We should via the pre-treatment of the GPS baseline data which a small number of bad satellite data or satellite can be removed,before improved the clearance conditions of GPS observations.So that you can ensure the GPS network reliability and stability better;8.Effectively increasing the observation time can improve the high-speed railway network of GPS control the overall accuracy. But increasing the observation time will not be absolutely to be able to raise the accuracy of the baseline and closed-loop.To the unity of the quality of observational data,it is the best to choose the unified observation time.9.Three fitting model can all meet the four-class levels precision requirement.Taking superiority of precision as consideration,in a small area,multi-faceted function is better than linear polynomial function model,and the quadratic polynomial function model is superior to multi-faceted function;In terms of the area with high topography relief,the multi-faceted function fitting model and mobile fitting model have considerable advantage,But using the polynomial fitting in whole region,the gross error is too high to ensure reliability and rationality.So it' s very important to choose the right fitting model in the processing of elevation fitting in the area where the terrain Undulating in a wide range.By researching on construction technology of sophisticated control measurement network of high-speed railway engineering,above conclusions can be a supplement of high-speed railway engineering survey techniques, which have certain references value to our high-speed railway track technology research.