铁路工程GNSS平面控制网复测相关研究及探讨

Research and Discussion on Repetition Survey of GNSS Horizontal Control Network in Railway Engineering

对目前TB10101—2018《铁路工程测量规范》和TB10601—2009《高速铁路工程测量规范》还未涉及的GNSS平面控制网复测的相关技术进行研究和探讨,为将来规范修订提供一些参考和建议。以多个铁路工程控制网复测项目为例,结合控制网复测的工程实践经验,对自由网相似变换方法中选取已知点、二次复测是否需要更新坐标、超限点更新坐标是否合理等问题进行分析和探讨。研究表明,采用自由网相似变换方法选取已知点,可避免将已发生2~4 cm位移的控制点误用作已知点;采用坐标较差和坐标增量之差的相对精度两个限差技术指标配套检核,可用于判别二次复测后是否需要更新坐标,以及超限点更新坐标是否合理。大量复测数据证实,该方法可用于指导控制网复测作业。

This paper studied and discussed the related technologies of resurvey of GNSS horizontal control network,which were not covered in the Code for Railway Engineering Survey(TB10101—2018)and Code for High-speed Railway Engineering Survey(TB10601—2009).The conclusion could provide references and suggestions for the revision of the code in the future.Taking several railway engineering control network repetition survey projects as examples,combined with the engineering practical experience of control network repetition survey,the author analyzed and discussed the discrimination methods of selecting known points by using the free network similarity transformation method.The necessity of updating coordinates for secondary repetition survey,and updating coordinates for out of limit points were discussed.From the analysis of the repetition survey data results,the known points can be selected by using the free network similarity transformation method,which could avoid misusing the control points with 2~4 cm displacement as the known points.The two tolerance technical indexes of relative accuracy of coordinate difference and coordinate increment difference were used for supporting inspection,which could be used to judge whether the coordinates need to be updated after the secondary repetition survey and whether the update coordinates are reasonable.A large number of repetition survey data suggest that,the method is feasible to guide the repetition survey of control network.