Enhanced suppression of seismic noise effect via active vibration isolation in torsion pendulum testing for space-borne inertial sensors

Precision torsion pendulums can be used to test space-borne inertial sensors with measurement ranges significantly smaller than Earth's surface gravitational acceleration. In this system, the gravity on the test mass is counterbalanced by the tension of the suspension fiber, enabling the sensor to enter its operational state. Through optimized design configurations, the system can effectively suppress the effects of ultra-low-frequency (around several mHz) seismic noise. This study addresses the mid-to-high frequency ground vibration effects, which conventional torsion pendulum schemes fail to suppress, proposing a novel torsion pendulum testing scheme integrated with an active vibration isolation system. This article introduces the design and theoretical analysis of an inertial sensor testing system with this scheme and shows the experimental validation of the improved seismic effect suppression. The experiments demonstrate that isolating mid-to-high frequency ground vibrations improves the noise floor testing of the inertial sensor, with the measured noise reaching the level of about 2 × 10-10 m/s2/Hz1/2, which reveals the intrinsic noise of the inertial sensor.