The Taiji mission, a pioneering Chinese space-borne gravitational wave observatory, requires ultraprecise calibration of its gravitational reference sensors (GRSs) to achieve its targeted sensitivity of $3\times {10}^{-15}\mathrm{m}{\mathrm{s}}^{-2}{\mathrm{Hz}}^{-1/2}$. Maintenance of this precision is challenged by time-varying scale factor drifts and dynamic center-of-mass (c.m.) offsets between the test masses (TMs) and spacecraft, driven by such factors as propellant consumption, thermal effects, and aging electronics. We develop an advanced in-orbit calibration framework that simultaneously estimates the GRS scale factors and c.m. offsets between TMs and spacecraft through a combination of spacecraft maneuvers and a Kalman filter. By applying periodic torque signals to induce controlled spacecraft angular accelerations, we leverage star tracker and GRS readouts to disentangle coupled disturbances and achieve dual-parameter calibration with remarkable precision, with scale factor errors below 0.2% and c.m. offset residuals within $100\text{μ}\mathrm{m}$, satisfying the Taiji-2 calibration requirements. This method is robust across different satellite configurations. The results not only ensure the feasibility of Taiji-2’s scientific objectives but also establish a scalable calibration paradigm for future missions, such as Taiji-3, where submicrometer c.m. stability and ultralow noise gravitational reference will be essential.

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• Classical mechanics
• Gravitational wave detection
• Gravitational waves
• Metrology
• Optical interferometry
• Space science
• Gravitational wave detectors
• Precision measurements