Research On Application Of BDS In Railway Engineering Control Survey

The Beidou Satellite Navigation System(BDS)is a satellite navigation system that independently developed and operated by my country.On June 23,2020,the last satellite deployed by the Beidou-3 system was successfully launched and incorporated into orbit,thus BDS entered global service new stage.In order to promote and strengthen the application of the Beidou satellite navigation system in railway construction and operation,relevant national departments have jointly launched a comprehensive application demonstration project for the Beidou railway industry,which includes demonstration projects in railway engineering surveying.Led by the BDS-based railway engineering survey demonstration project application,Beidou and railway engineering survey will be further integrated to promote the healthy development of the two industries and serve the construction of the national comprehensive three-dimensional transportation network.For this reason,it is necessary to conduct systematic research and experimental verification on the relevant application technology of BDS in railway engineering survey.First,a certain length of railway GNSS horizontal control survey experimental network was established in the Bangda grassland area of Qamdo near the Sichuan-Tibet railway line,and then a certain type of Beidou survey receiver and American Trimble GNSS receiver were used in the experimental network to carry out railway CPI and CPII,and the measurement experiment of the GNSS plane control network outside the tunnel.Finally,the data processing and analysis of the measurement experiment observation data based on different types of receivers and different satellite constellations verify the feasibility of a single BDS to establish high-speed railway CPI,CPII and GNSS plane control networks outside tunnels in high-altitude areas,and proves that the baseline vector accuracy of this Beidou survey receiver is good,which is consistent with the results of the existing mainstream Trimble receiver.Then the network design,measurement method and data processing technology of the new CPI and CPII control network of Xuanhang Railway based on the BDS foundation enhancement system are studied,and combined with the accuracy requirements of railway engineering measurement,the new CPI of Xuanhang Railway based on single BDS is studied.And the statistical analysis of the baseline quality of the CPII control network and the network adjustment results proves that the new CPI and CPII control network established by using a single BDS can meet the accuracy requirements of the corresponding level of general-speed railway engineering survey.Then through the data processing and analysis of the BDS-based Xuanhang Railway strip elevation fitting measured data,it is verified that its accuracy can meet the requirements of third-class leveling.The research results also show that the elevation fitting accuracy of a single BDS and a single GPS is equivalent.Finally,the accuracy comparison and analysis of the results after the CPI and CPII control network of the Guangzhou-Zhuhai Intercity Railway using single BDS and single GPS baselines are used to verify the GNSS static relative positioning measurement method based on single BDS in the active low-latitude ionosphere regions Obviously better than GPS in terms of accuracy and reliability of measurement results.Then,the technical route and stable starting point selection method of the CPI,CPII and CPIII plane network retesting of the Guangzhou-Zhuhai Intercity Railway were studied,and it was verified that this method can make the CPII control network based on BDS and the intelligent total station based The CPIII plane network has good accuracy compatibility.