数字闭环光纤陀螺死区非线性机理

死区非线性是数字闭环光纤陀螺的非线性误差之一,抑制死区非线性可以减小数字闭环光纤陀螺的输出噪声和漂移.分析了死区与分辨率和阈值的关系,给出了数字闭环光纤陀螺死区的定义和测量方法.提出调制信号与探测器输出信号之间的电交叉耦合及进入相位调制器的调制误差信号是产生死区的干扰源.给出了干扰信号的频率和相位特征,并分析了干扰信号跟踪、锁定输入信号的过程.将反馈干扰通道的部分积分模型和理想的数字闭环光纤陀螺模型结合,建立了带死区的陀螺模型.基于陀螺模型及相位调制信号与死区的关系,推导出了死区产生的条件及死区造成的陀螺输出偏差.死区影响因素的仿真结果和实验结果验证了陀螺模型和死区产生条件的正确性.

Dead band nonlinearity of digital closed-loop FOG

Dead band nonlinearity is one of nonlinearity errors in digital closed-loop fiber optic gyroscope(FOG).Output noise and drift of FOG can be reduced by attenuating dead band nonlinearity.Based on the definition of the resolution and threshold for FOG,a dead band definition and test method in digital closed-loop FOG were proposed.The frequency and phase characteristic of interfering signal and the process that the interfering signal tracked and locked input signal were analyzed to prove that electrical crosstalk between phase modulator and photodetector and modulation error were main interference sources causing dead band.A dead band model of digital closed-loop FOG was developed by combining an ideal digital closed-loop FOG model and a partial integration model of interfering channel,and a condition expression of dead band and an expression of output error produced by dead band were derived from the dead band model.The simulation results of the dead band are identical with the experimental results of the dead band,which indicate that the dead band model of digital closed-loop FOG is accurate.