独立坐标系适应地铁规范测量精度的改造方法研究

Research on the Transformation Method of the Independent Coordinate System to Adapt to the Measurement Accuracy of Subway Norms

我国许多城市的独立坐标系依据1985年颁布的《城市测量规范》要求建立,规范要求“城市平面控制测量坐标系的选择应以投影长度不大于2.5cm/km为原则”。然而随着技术水平的提高,地铁线路控制网要求综合变形值不大于1.5cm/km,因此,需要在原有的控制网基础上计算新的首级控制网。该文研究了高斯投影、斜轴墨卡托投影与膨胀椭球法结合建立抵偿坐标系的方法;在此基础上,应用理论计算了重庆轨道交通9号线1期与24号线1期的80个首级控制点的抵偿坐标,将计算的抵偿坐标的反算距离与高精度实测边长比较;通过计算结果分析,进一步说明了所用方法在投影变形中的优缺点。

The independent coordinate system of many cities in China was established according to the requirements of Code for Urban Survey promulgated in 1985,and the specification requires that“the selection of the coordinate system of the city plane control measurement shall be based on the principle that the projection length shall not be greater than 2.5cm/km”.However,with the improvement of technical level,the comprehensive deformation value of the subway line control network is required to be no more than 1.5cm/km.Therefore,a new first-level control network needs to be calculated on the basis of the original control network.In this paper,the method of establishing a compensation coordinate system by combining Gauss projection,oblique axis Mercator projection and the expanded ellipsoid method is studied.On this basis,the compensation coordinates of 80 first-level control points of Chongqing Rail Transit Line 9 Phase 1 and Line 24 Phase 1 were calculated by applying theory,and the inverse distance of the calculated offset coordinates is compared with the measured edge length with high precision;Through the analysis of the calculation results,the advantages and disadvantages of the proposed method in projection deformation are further explained.