为了实现大空间几何量测量的全局定向和精度控制，需要在空间内构建精密三维坐标控制场。目前，利用激光跟踪仪单站建立坐标控制场是最有效手段，但面对局部更高的测量精度需求，必须减小全局定向过程中的转站误差，增强区域的控制场精度。利用激光跟踪仪干涉测距精度高的特性，并用跟踪仪靶球座配合碳纤维杆现场构造多个空间长度基准(微米量级精度)，长度基准可灵活布置于所需空间区域，作为约束加入到跟踪仪多站位对控制点的冗余测量过程当中，从而克服单站空间遮挡问题并优化跟踪仪测角误差，进一步提高所构建长度基准的控制点坐标精度，实现区域测量场的精度增强。实验结果表明，该方法可使全局定向精度在10 m 测量范围内优于0.04 mm，进一步满足现场大空间几何量测量的高精度要求。

In order to achieve global orientation and accuracy control in large space geometric measurement, precise three-dimensional coordinate control field need to be established. Using a laser tracker to establish coordinate control field by single station is the most effective means recently. But in face of higher accuracy in local area, coordinate transform error between stations must be reduced in the process of global orientation, and accuracy of control field in the region must be enhanced. By using high accuracy ranging interference of laser tracker, multiple spatial length standards are constructed with carbon fiber rods and target ball seats, and arranged flexibly in the desired region in the space. In the process of using a laser tracker to make redundant measurement of control points by multi-station, length standards are added as constraints to overcome space occlusion and optimize tracker angle measurement error, further improve the coordinate accuracy of control points used to construct length standard, thus enhance the local field measurement accuracy. The experimental results show that accuracy of global orientation is better than 0.04 mm in the range of 10 m with this method, which meets high accuracy requirement of large space geometric measurement.