差分法三角高程在地铁CPⅢ测量中的应用

Application of difference method trigonometric elevation in subway CPⅢ measurement

当误差存在较强的相关性时,运用差分思想对测量元素求差,可有效消除或减弱相关性误差影响.在地铁CPⅢ测量中,利用差分法构建一个虚拟的间接高差,以消除大气折光和地球曲率(球气差)影响.结果表明,利用该方法构建的CPⅢ高程网可以有效满足地铁铺轨要求.

When there was the strong correlation between errors,the difference idea was used to calculate the difference of measuring elements,which could effectively eliminate or weaken the influence of correlation error.In the subway CPⅢsurvey,a virtual indirect elevation difference was constructed by using the difference method to eliminate the influence of atmospheric refraction and earth curvature(spherical air difference).The results showed that the CPⅢelevation network constructed by this method could effectively meet the requirements of subway track laying.