该文详细介绍沉降观测基准点、沉降观测点布设过程及观测方法，介绍使用的观测仪器、计算软件及观测精度；
In this paper, datum marks of settlement observation, layout of observation points, observation methods, observation instruments, calculation software and observation precision are introduced.
结合仪器的特点，对用于上架式陀螺经纬仪的逆转点定向方法进行改造，提出了逆转点定向方法在下架式陀螺经纬仪中进行观测的原理和方法。
Reform the definite orientation method used for up the pose gyrotheodolite, put forward the principle and the method of converse point to definite orientation at under the pose gyrotheodolite.
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