采用相关辨识的光纤陀螺动态特性测试方法

Dynamic characteristics test of fiber optic gyroscope based on cross-correlation identification

动态特性是光纤陀螺的一项重要技术指标,传统的机械转台无法提供测试条件。提出了一种基于相关辨识的光纤陀螺动态特性测试方法;根据全数字闭环光纤陀螺采用数字阶梯波反馈实现闭环控制的工作原理,通过在闭环反馈信号中叠加伪随机信号的方法来进行动态特性测试。将反馈阶梯波上叠加的伪随机信号作为辨识输入信号,光纤陀螺闭环数字输出作为辨识输出信号;将数字闭环输出经过小波滤波后的信号与伪随机信号进行相关运算后得到陀螺闭环回路的脉冲响应,再通过傅里叶变换得到陀螺的幅频和相频特性。利用该方法获得的光纤陀螺动态特性与利用正弦波叠加方法得到的结果具有一致性,证明了该方法的有效性。且该方法具有易于实现,适合实际工程应用。

Dynamic characteristic is important to the fiber optic gyroscope,and it is difficult to test with traditional mechanical equipments.A method based on cross-correlation identification was proposed to realize the dynamic characteristic test.Considered the principle of digital closed-loop fiber optic gyroscopes which adopted the digital step feedback to realize closed-loop control,the method was designed by means of adding pseudo random binary signal（PRBS） to the feedback serrodyne.The PRBS was the identification input signal and the closed-loop output was the identification output signal.After the wavelet filtering,the closed-loop output was correlated with PRBS to get the impulse response,and then fast Fourier transform was used to get the amplitude-frequency and phase-frequency characteristics.The testing result of the cross-correlation identification is compared with that of the previous method and shows that they are basically consistent.The cross-correlation identification is effective,easy to realize,and more fit for practical engineering test.