A distance-constrained adjustment method for dynamic measurement using a laser tracker network and its accuracy evaluation

The laser tracker plays an important role in large-scale, high-accuracy measurement fields due to its exceptional accuracy and strong dynamic performance. For dynamic measurement tasks, using a laser tracker network measurement system is both effective and efficient. In current research on the laser tracker network, once the reference coordinate system is unified, raw observations from each station are used directly without adjustment, which limits further improvements in dynamic measurement accuracy. To address this issue, a dynamic measurement adjustment method based on distance constraints is proposed. First, four fixed points are placed on the moving target, and the distances between these points are computed using the trilateration network adjustment. These distances are then used as constraints for adjusting dynamic measurement data over time. In the user manual for Leica AT960/AT930 laser trackers, the static measurement accuracy is specified according to the ASME B89.4.19-2006 standard. However, no explicit specification is provided for dynamic measurement accuracy. To address this, the paper proposes a method for evaluating the dynamic measurement accuracy of a networked laser tracker system. Finally, a dynamic measurement system was established using a synchronization trigger and four laser trackers, and experiments were conducted with a tetrahedral artifact as the target. Experimental results show that the dynamic measurement accuracy improves by more than 70% after adjustment.