A Systematic Approach for Calibrating the Inertial Sensor of Taiji-1

High-precision inertial sensors can provide us references of free-falling motions in gravitational field in space,and will serve as the key payloads of the future space-borne Gravitational Wave antennas such as LISA and LISA-like missions (Taiji, Tianqin, etc.). Taiji-1, launched in AUG 2019, was the first technology demonstration satellite of the Taiji Program in Space, and one of its main objectives is to demonstrate the performance of the inertial sensor and test the related technologies. In this work, a new and systematic approach for calibrating the basic operating parameters of Taiji-1's inertial sensor or similar electrostatic inertial sensors is introduced. Based on the calibration principles, a swing maneuver for about 200 s and a rolling maneuver for 19 days were conducted by Taiji-1 in 2022. The operating parameters including scale factors, center of mass offset vector and the intrinsic biased accelerations are precisely re-calibrated and updated to the Taiji-1 science team. Data from one of the sensitive axes is re-processed with the updated operating parameters, and the performance is found to be improved compared with former results. This approach could also shed some light on the in-orbit calibrations of the ultra-precision inertial sensors for future GW space antennas, since the principle and technology inheritance between these two generations of inertial sensors.