Performance Evaluation of Rotational Seismometers: Noise Characterization and Comparative Analysis

Abstract In recent years, fiber optic rotational seismometers, with fiber optic gyroscopes as their core sensors, have undergone rapid development. These seismometers are characterized by high sensitivity, wide bandwidth, and portability, making them suitable for both standard observatory and portable field observations, and can contribute to multiple applications. Through synchronous observations at the Baijiatuan Observation Station of the Beijing National Earth Observatory, we compared continuous noise records of four new prototypes of fiber optic rotational seismometers, including two three-component and two single-component rotational seismometers. Power spectral densities of ambient noises, self-noise assessment via the dual-station synchronous measurement, and Allan deviation revealed that the accuracy of all four prototypes can reach precision of blueSeis-3A, the most famous commercial product of fiber optic seismometers at present. The comparison of design schemes between four prototypes reveals the effect of gyroscopes’ parameters, such as the length of fiber optic, the diameter of gyroscope on its performance. Finally, from the perspectives of underground observation and the requirements for ultra-sensitive rotational motion recording, we discuss what should be done in the next to further improve natures of these fiber optic rotational seismometers, and explore different applications at interdisciplinary fields.