非均匀采样条件下光纤陀螺微小角振动信号检测技术

航天器在轨运行过程中,由于内部存在多种活动部件,会使结构体产生微小角振动,微小角振动呈现振幅较小、频率较高的特点,微小角振动会造成光学载荷成像质量的下降。光纤陀螺从组成原理上具有宽频带和高灵敏度的特点,能够输出采样周期内的角度增量,可以作为微小角振动测量部件。但是,基于航天器整体时序的综合考虑,无法对光纤陀螺进行均匀采样,提出了非均匀采样条件下的频谱分析方法,将经过非均匀采样得到的整周期时间序列进行傅里叶变换,得到原始信号的幅值和频率,进而实现微小角振动的高精度检测。通过数字仿真和六自由度微振动台试验验证了上述方法的可行性,检测精度优于0.04。

Signal detecting technique of FOG's micro angle vibration under nonuniform sampling

During the spacecraft's in-orbit running, its structure could get a micro angular vibration due to various moving parts inside, which has relatively small amplitude and high frequency and could result in quality reduction of the optical load's imaging. With broad bandwidth and high sensitivity, the FOG can output angular increment in a sample cycle, making it the perfect sensor of micro angular vibration. But FOG can't be sampled evenly considering the spacecraft's whole scheduling. This paper proposes a frequency spectrum analysis method for nonuniform sampling, which transforms time sequence in a complete nonuniform sampling cycle to the fourier space to obtain original signal's amplitude and frequency so as to achieve high precision measurement of the micro angular vibration. The method has a precision better than 0.04, which was validated by digital simulation and 6-DOF micro vibration test.