INTERGEO Agenda - english

Spherically mounted reflectors (SMR) are frequently used in industrial metrology, especially in laser tracker applications. An SMR consists of a mirrored corner cube centered in a steel ball with a typical radius of 1.5”. In contrast to highly precise but expensive SMRs, low-cost spherical glass-body reflectors and related accessories for classic terrestrial applications are available. Hence, different types of instruments, such as levelling instruments, total stations, laser scanners, or laser trackers, can be combined via a direct physical connection in a unified network. The necessary condition is an identical and instrument-independent point of reference. In this study, the suitability of spherical glass-body reflectors for precise industrial applications was evaluated. For this purpose, the quality of the workmanship of more than twenty reflectors from different production series was investigated using Leica’s laser tracker AT960. The conformity of the centering, the zero-point offset, the ball radii, and the sphericity were examined and compared to higher-order references. Moreover, the impact of a misaligned reflector on polar observations was studied. Appropriate corrections were derived for each reflector under investigation to ensure their suitability in industrial metrology. At the Onsala Space Observatory, the gravity-induced deformation behavior of a radio telescope’s main reflector was studied using industrial photogrammetry. The investigated glass-body reflectors were successfully used to establish a long reference scale exceeding the main reflector’s diameter during the measurement process.