Resonance Suppression of a High-Inertia Two-Axis Turntable in ATP Systems for Space Optical Communication

In space optical communication, acquisition, tracking, and pointing (ATP) subsystems rely on high-inertia two-axis turntables for precise line-of-sight alignment. However, larger apertures and lightweight designs reduce mechanical stiffness, inducing resonances that severely degrade pointing accuracy and disturbance rejection, thereby compromising link stability. To address this issue, this paper proposes an algorithm integrating resonance frequency identification and filter suppression for high-inertia two-axis turntables. The proposed method employs a Goertzel-based resonance parameter search mechanism utilizing an adaptive threshold golden section algorithm. This mechanism rapidly and accurately identifies the center frequency, bandwidth, and depth of system resonances, suppressing them via a pre-distorted notch filter. Furthermore, a sliding Goertzel algorithm is employed for real-time resonance frequency monitoring, enabling error-based parameter adaptation to optimize closed-loop response. Both frequency-domain analysis and time-domain experiments validate the effectiveness of the approach. Experimental results demonstrate that the proposed control strategy effectively suppresses the dominant resonant modes, reducing the standard deviation of the pointing error from $4.7\times {10}^{-3}{}^{\circ }$ to $1.0\times {10}^{-4}{}^{\circ }$ and that of the constant-speed tracking error to $0.006{}^{\circ }/\mathrm{s}$. Compared with conventional methods, the proposed approach achieves superior performance in steady-state pointing accuracy and disturbance rejection, significantly strengthening the ATP system’s performance and contributing to more reliable space optical communication links.