为了实现受限空间内的精密坐标传递, 建立了二联激光跟踪仪测量系统, 并设计了其施测及数据处理方法。首先, 对Leica AT402激光跟踪仪进行改装, 在其提手上安装能够放置球棱镜的靶座, 并精确标定球棱镜中心与仪器中心的高差, 称它为垂向偏心差。然后, 两台激光跟踪仪自由设站, 双面互瞄对方提手上的球棱镜, 并依据垂向偏心差将互瞄观测值改化至仪器中心, 得到仪器中心之间的互瞄观测值。两台仪器分别测量可视范围内的目标点, 当两台仪器能够观测到足够数量的公共点时, 可利用公共点和互瞄观测值共同传递坐标和方位; 当无公共点时, 可利用激光跟踪仪之间的互瞄观测值传递坐标和方位。在上海光源的工程控制网内开展了测量实验, 结果表明: 当相邻测站有公共点时, 该系统能提高坐标转换的精度; 当无公共点时, 在9 m的距离上, 坐标传递精度优于0.22 mm, 定向旋转角精度接近1″。该系统可应用于三维工程控制网的测量, 尤其适用于通视条件差的精密坐标传递场景。

In this work, a two-laser-tracker system was developed, and its measuring and data processing methods were designed to precisely transmit coordinates in a limited space.First, two Leica AT402 laser trackers were modified, and two target seats were respectively installed on their handles to place spherical prisms. Thereafter, the height difference between the adapter center and instrument center was precisely calibrated as vertical eccentricity. Furthermore, the two laser trackers set up survey stations and aimed at the sphere prism on the handle of the other instrument. The observed values should be adjusted to the instrument centers considering the vertical eccentricity to obtain the aiming interaction observation between the instrument centers. Moreover, the two instruments measured the target points in the visible range. When the two laser trackers could observe sufficient common points, the common points and the aiming interaction observation could be used to transmit coordinates and orientation simultaneously. When there was no common point, the aiming interaction observation was utilized to transmit the coordinates and orientation. Measurement experiments were carried out in the engineering control network of the Shanghai Synchrotron Radiation Facility. The experimental results show that when there are enough sufficientpoints in adjacent stations, the accuracy of coordinate transmission can be improved using the aiming interaction observation. When there is no common point, at 9 m, the precision of transmitted coordinate accuracy is better than 0.22 mm, and the precision of the directional rotation angle is approximately 1″. This system can be applied to the measurement of a three-dimensional control network, and is especially suitable for precise coordinate transmission inpoor visibility conditions.