Design and experiment of a four-station laser tracker multilateration measurement system and evaluation of uncertainties.

This article focuses on the design, uncertainty analysis, and validation of a four-station laser tracker multilateration measurement system (FLTMMS) developed to improve the pre-alignment accuracy of the Hefei Advanced Light Facility (HALF), a fourth-generation low-energy synchrotron radiation device. The FLTMMS design model incorporates geometric relationships and strict constraints on the incidence angle (≤20°) to the reflective target spheres (Red Ring Reflectors) to prevent accuracy loss during measurements. Using the Monte Carlo method, the authors evaluated the system's measurement uncertainty, finding coordinate uncertainties below 10 μm, which meets HALF's pre-alignment requirements. The uncertainty estimates were further validated through internal inspection of system parameters and external comparison with a calibrated standard tetrahedron, confirming the reliability and precision of the FLTMMS for high-accuracy accelerator alignment tasks.