Measurement uncertainty evaluation model of field type circle time-grating sensor

A sensor uncertainty evaluation model that meets international GUM standards can provide a theoretical foundation for optimizing sensor structure parameters. In this study, a field type circle time-grating sensor was taken as the research object to build an effective uncertainty evaluation model. First, four main uncertainty sources of the field type circle time-grating sensor were found by deducing the mathematical expression of angle measurement and analyzing the sensor uncertainty sources. Second, the transitive relations between the main uncertainty sources and synthetic uncertainty were analyzed and deduced, respectively. Finally, an uncertainty evaluation model with all the main uncertainty sources was built based on modern uncertainty theory. A field type circle time-grating sensor with 72 poles was tested to verify the effectiveness of the proposed uncertainty evaluation model. The results indicated that the evaluation process in the experiment meets the international GUM standards. The peak-to-peak value of the measurement error for the whole week of the field type time grating in this study was 12.09′′. This value was in agreement with the 12.73′′ calculated from the formula of measurement uncertainty evaluation of the field type time grating, which can be used for the actual evaluation of field time grating measurement uncertainty. Moreover, the analysis results can provide a theoretical basis for the optimal design of the time grating sensor structure.