利用信号相关性抑制光纤陀螺强度噪声

提出了一种利用陀螺干涉信号和耦合器空闲端信号相关性估计光源强度噪声抑制效果的方法,并在现场可编程门阵列(FPGA)中进行了实时估计.根据估计结果,判决是否进行强度噪声相减,以提高光纤陀螺强度噪声抑制方法的可靠性.理论分析表明,强度噪声抑制效果与信号相关性直接相关.利用该方法,对某高精度干涉型光纤陀螺进行了实验.结果表明,当陀螺干涉信号和耦合器空闲端信号互相关系数为0.91时,干涉信号噪声方差降低至17.16％,然而,当上述互相关系数为0.28时,噪声相减法反而使干涉信号噪声方差增大至143.18％,由此验证了理论分析结果.利用该方法可以在线检测陀螺干涉信号和耦合器空闲端信号的相关性,进而避免噪声相减法中当陀螺干涉信号和耦合器空闲端信号相关性较差时,光纤陀螺噪声不降反升的情况,提高了强度噪声相减法的可靠性.

Suppression of relative intensity noise for FOG by using signal cross-correlation

A method to estimate the efficiency of relative intensity noise subtraction for a Fiber Optic Gyroscope(FOG) was proposed,and the estimation result could be used to improve the reliability of relative intensity noise subtraction of the FOG.Theoretical analysis shows that the efficiency of relative intensity noise subtraction of the FOG is highly dependent on the cross-correlation between the outputs of FOG and coupler.By proposed method,the experiment on a high precision interferometric FOG was performed,and obtained results show that when the cross-correlation coefficient is 0.91,the variance of the noise after subtraction reduces to 17.16%.However when the cross-correlation coefficient is 0.28,that of the noise after subtraction goes up to 143.18%.These results are coincident with that of theoretical analysis.By utilizing this method,the cross-correlation between the outputs of FOG and coupler improves the reliability of the intensity noise subtraction.