Abstract:The metrological standards of high-precision spherical coordinate scanning measurement systems are mostly limited to evaluating simple geometric features, making it difficult to meet the traceability requirements for full-field scanning accuracy of complex surfaces. Meanwhile, large curved surface standard devices face a bottleneck in maintaining high precision during calibrating high-precision spherical coordinate scanning systems due to the influences such as gravity and ambient temperature. To address the above difficulties, this paper proposes a calibration scheme based on large-scale physical surfaces. A large-scale combined standard device integrating concave, convex, and planar surfaces was innovatively designed to achieve comprehensive evaluation of the contour scanning performance of the measurement system. The proposed "segmented fabrication-precision assembly-thermal expansion release" structural design scheme utilizes an invar frame and an independently suspended thermal expansion release mechanism to suppress environmental thermal stress and gravity-induced deformation, enabling high-precision assembly of the large-scale standard device while ensuring long-term stability compliance. A high-precision reconstruction method for large-scale geometric digital models was developed to achieve accurate calibration of the high-precision spherical coordinate scanning measurement systems. Experimental results demonstrate that this method can control the assembly error tole-rance within 0.05 mm and reduce the RMS error to less than 0.01 mm, effectively supporting the establishment of accuracy traceability for the measurement system.