高速铁路精密测量基准的确定

Determination of Precision Measurement Datum for High-speed Railway

研究目的:既有高速铁路工程测量采用国家勘测基准,缺点是投影变形大,为确保测量精度,需要将工程区域划分成很多坐标系,这对线路连接和成果使用都很不利。因此,从高速铁路测量的特点和精度要求入手,研究适用于高速铁路精密工程测量的独立测量基准是非常必要的。研究结论:该方法以WGS84椭球为基准椭球,首先改变基准椭球的长半轴和偏心率,利用垂线偏差分量求得椭球中心的三个平移量,以及三个坐标轴的旋转角,并由此构造与施工区域平均高程面最佳拟合的区域椭球面,然后通过适当的地图投影方式来建立独立的精密测量基准。该基准特别适用于高速铁路的精密测量,同时也为CPⅢ的三维平差提供了理论依据。

Research purposes： If the national survey datum is used for the engineering measurement of high - speed railway, the projection distortion is big, and the project engineering area would be divided into many coordinate systems to ensure the measurement precision. In this way, influenced. Therefore, it is necessary to research the high -speed railway. the track join and the application of the measurement result will be independent measurement datum for the precise measurement for Research conclusions：In this paper, a new measurement datum is presented. That is to take the WGS84 as the datum ellipsoid to firstly changes the semi - major axis and eccentricity of the datum ellipsoid and then the three translation parameters of ellipsoid centre and three rotation angles of axis can be obtained by using the deflections of the vertical component to build an optimal fitting surface of local ellipsoid with the average elevations of the construction area; At last, the independent precise measurement datum is established with the appropriate map projection method. This method is not only available for the precise measurement for the high - speed railway, but also it can provide the theory basis for the CPⅢ 3D adjustment.