高速铁路CP0基线解算中起算点坐标精度研究

在高速铁路CP0基线解算过程中,需要将IGS参考站作为起算点,当起算点坐标出现误差或兼容性较差时,将导致整个框架控制网基线向量解产生系统性旋转和尺度变化,因此必须对起算点坐标的允许精度进行研究。介绍起算点误差传播与影响模型,从理论上分析起算点误差对基线解算的影响程度,通过设计不同解算方案采用工程测量数据对起算点坐标的允许精度进行研究。结果表明,使用GAMIT软件进行CP0框架控制网解算时必须严格控制起算点坐标的误差,起算点点位坐标精度最好控制在10 cm之内;当起算点坐标误差达到20 cm时,各基线分量的解算结果的精度在毫米级的量级;当起算点坐标误差达到2 m时,基线解算结果不可靠,不满足高精度解算要求。

Research on Accuracy of Initial Point Coordinate in Baseline Resolution for Frame Control Network of High-speed Railway

In the process of high speed railway CP0 baseline resolution,it is necessary to set IGS reference stations as an initial point. Error or poor compatibility in terms of initial points will cause systemic rotation and scale change of baseline vector resolution for the entire frame control network.Therefore it is necessary to conduct a research on the essential accuracy of initial point for CP0 baseline resolution. In this paper,firstly,the error propagation and influence model of initial point coordinates is introduced and a theoretical analysis of the impact of initial point accuracy on baseline resolution is performed,and then surveying data in different resolution schemes are analyzed to determine the essential accuracy of initial points. The results show that,initial point errors must be strictly controlled while GAMIT software is used to resolve CP0 baselines,and initial point error is controlled as its best within 10cm; when initial point error reaches 20 cm,each baseline component resolves in the millimeter level accuracy; when initial point error reaches 2 m,baseline resolution results are unreliable and can not meet the requirements of high precision calculating.