High Precision Angular Measurement via Dual Imaging Detectors

This paper proposes a novel error compensation arithmetic based on dual imaging detectors which can eliminate errors caused by grating eccentricity. First, we built an error model and analyzed the error change current. Furthermore, we deduced the error compensation arithmetic and established the dual-image-detector-based method. Finally, we conducted a series of experiments to test the performance of this arithmetic. The test results showed that we achieved a standard error deviation of 6.33^{\prime \prime } and grating diameter of only 38 mm. This arithmetic outperforms the single detector and is far superior to the traditional method. The results presented here may provide a theoretical foundation for further research on angle-displacement measurement.