| China’s high-speed railway is in a period of rapid development,the operational mileage has exceeded 40,000 km,high-speed railway operation speed,safety characteristics of highspeed railway control network has put forward more demanding requirements,with China’s BDS-3 liftoff,GNSS multi-constellation observation conditions have been significantly improved,if the BDS-3 satellite data can be introduced in the process of high-speed railway control network data processing,not only to provide more high-speed railway construction If BDS-3 satellite data can be introduced in the process of high-speed railway control network data processing,it will not only provide more powerful safety guarantee for highspeed railway construction,but also provide useful opinions for BDS-3 development.At present,there are very few high-speed railroad control network solving software that can handle BDS-3 data,in view of this,this paper develops a set of high-speed railway control network solving software capable of handling BDS-3 data around TB 10601-2009 "Specification for High-speed Railway Engineering Measurement" and analyzes the performance of this software.The applicability of the observation time index in the existing specification after the introduction of the new generation of Bei Dou satellite navigation system is evaluated and analyzed.The specific research work is as follows.(1)GNSS high speed railway control network data processing process and BDS-3satellite availability analysis.The constellation status of BDS-2/BDS-3 is introduced,and the satellite visibility number and PDOP value distribution characteristics of BDS-2/BDS-3in the service area are analyzed by global DEM,and the results showed that BDS-3 can significantly improve the service capability of BDS in the global area and improve the positioning accuracy.(2)BDS-3/GNSS high speed railway control network solving software was developed.Based on the software called Common GPS Office(CGO)added BDS-3 satellite parameters,user interaction,leveling calculation and optimized acceleration modules.The BDS-3/GNSS high speed railway control network solving software was developed according to the high speed railway specification,which realized the automatic processing of CPI and CPII multi-time control network data.The reliability of the software was verified by comparing and analyzing the solution results with TBC of Trimble and Cosa GPS using the measured data.The results show that the root-mean-square error of the baseline vectors is within mm of the TBC results of Trimble,and 94% of the baseline vectors are within 10 mm.The unconstrained leveling coordinates are the same as the Cosa GPS results,and the error in each direction is basically the same.(3)Data processing and experimental analysis of high-speed railway control network.The quality check of the CPI control network data of the high-speed railway was carried out by using the self-programmed software,and the results showed that the indicators of the network,such as poor repeat baseline,poor synchronous ring asynchronous ring and network parity,met the requirements of the high-speed railway specification,and the control network accuracy was qualified.The a priori model of baseline solution accuracy with observation time was derived,and the results showed that the relative positioning accuracy of BDS+GPS(observation time of about 17 min)in the a priori model was comparable to that of single GPS(observation time of 60 min).The results of the baseline solution using the CPII control network data of high-speed railways as an example and the self-programmed software show that the positioning accuracy of GPS+BDS is 4.3mm and10.9mm in plane and elevation directions respectively,which is 54% and 57% better than that of single GPS,and the baseline solution test with different time lengths is conducted with the data,and the results show that GPS+BDS adopts 34% of the observation time in the specification.The results show that the results of GPS+BDS using 34% of the observation time in the specification are comparable to the results of single GPS according to the original observation time in the specification,which has certain reference value for GNSS rapid measurement and the next revision of the specification. |
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