城市轨道交通GPS控制网复测结果评估

理论推导出复测点位较差的中误差限差。以某市地铁5号线GPS控制网复测为例,首先检核复测GPS控制网基线质量、三维无约束平差和二维约束平差的质量是否满足相应的规范要求。在保证复测成果满足要求时,将本次复测坐标成果与2009年原测坐标成果进行对比和分析,所有GPS控制点均满足点位坐标较差不大于25mm、点位较差不大于34mm的规范限差要求,可以认为这些GPS点位无显著变化,GPS控制网稳定,GPS控制网的原坐标成果可以继续使用。

The Evaluation of the GPS Control-Net-Based Resurveyed Result of the Municipal Track Traffic

Upon the basis of theoretically deriving the medium error tolerance of the re-measurement points, and with the GPS control net-based resurvey of the 5th line of the subway of a certain city as a practical example, the reiteration of the GPS baseline quality is checked first to see whether the quality of the three-dimensional control network of unconstrained adjustment and that of the two-dimensional constraint adjustment are up to the requirements of the technical specifications. When the resurveyed results are ensured to be up to the requirements, the resurveyed results of the coordinates are compared with the previously surveyed results of the coordinates obtained in 2009,and analyzed to ensure that all the GPS control points can meet the requirements the coordinates of the points, with the relative error of their location limited to no more than 25 mm,and the relative error of the points no more than 34 mm prescribed in the tolerance requirements of the technical specifications. Upon these bases,it can be concluded that there is no obvious change in the location of these GPS points, the GPS control network is stable, and the results of the original coordinates of the GPS control network can continue to be used.