Error Characterization of Laser Scanner-based Metrology for Large Reflector Antennas: Effects of Tilt and Measurement Noise

Abstract

Terrestrial laser scanners (LS) are increasingly applied in large-reflector antenna metrology, but the impact of LS tilt, two-face calibration, and intrinsic random noise has not been quantitatively assessed. This paper presents the first systematic characterization of these error sources for LS-based reflector measurement. A controlled laboratory experiment with nine FARO spheres scanned between 0° and 80° revealed a small linear dependence of baseline residuals on the tilt angle (≈0.005 mm/degree). Two-face measurements confirmed calibration stability under tilt, with differences ≤ 0.5 mm (1σ). Monte Carlo propagation of range and angular noise introduced an additional 0.1–0.2 mm (1σ) variability in surface RMS. These contributions were combined into an uncertainty budget according to the guidelines of GUM, resulting in a combined standard uncertainty of 0.65 mm (1σ) and an expanded uncertainty (k = 2) of 1.3 mm. These results establish quantitative limits on LS-induced error under significant tilt and demonstrate that LS-based metrology remains robust for large-reflector applications, providing a basis for assessing electromagnetic performance.