Taiji drag-free and attitude control system: Modeling and end-to-end simulation for the science mode
Phys. Rev. Applied 26, 044090 – Published 29 October, 2026
DOI: https://doi.org/10.1103/nrs6-99jc
Abstract
In the Taiji project—a Chinese space-borne gravitational wave detector—the drag-free and attitude control system (DFACS) is the core technology responsible for maintaining the inertial motion of the test mass (TM). A thorough understanding of the spacecraft (SC) dynamic behavior under complex gravitational perturbations and multisource nongravitational disturbances is crucial for optimizing control system design, studying data processing pipelines, and verifying the detector performance. In this paper, we propose a unified simulation framework integrating the constellation orbital motion with a full-state closed-loop DFACS system and develop a 60-degrees-of-freedom (DoF) DFACS simulator. Furthermore, benefiting from the introduction of high-precision numerical methods, the simulator is extended to 31 significant digits, which supports high-fidelity numerical simulations of the intersatellite laser interferometry measurements from picometers to million kilometers. Three different experiments are implemented to assess the performance of DFACS by analyzing the single TM’s residual force noise, moving optical subassembly’s jitter, and the arm-length variation of TM-TM and SC-SC. Moreover, we quantitatively demonstrate the feasibility of decoupling DFACS design and orbit optimization. For the Taiji project, this study enables a more realistic on-orbit simulation of the detector and provides a representative system response under closed-loop control, supporting more accurate detector sensitivity analysis and facilitating refined optimization for scientific objectives.
