【作者】 陈世同；

【导师】 孙枫；

【作者基本信息】 哈尔滨工程大学 ， 精密仪器及机械， 2009， 博士

【摘要】 近30年来,光纤陀螺作为一种新型惯性敏感器件在国防领域得到了广泛的应用。在国外,随着光学器件的加工工艺和关键技术的突破,高精度光纤陀螺也进入了使用阶段。在国内,由于光学器件的加工工艺和某些关键技术尚未突破,高精度光纤陀螺还停留在实验室阶段。尤其是高精度光纤陀螺的建模技术和信号处理技术,仍处于初步探索阶段。经研究发现,光路参数、电路参数以及调制解调的方法都会约束光纤陀螺精度的进一步提高,所以建立高精度光纤陀螺的光学模型与电路控制模型非常有意义。本文在前人的工作基础上,提出了基于四状态的双闭环调制解调技术,对光纤陀螺光路模型和闭环控制电路的数学建模进行了深入的研究,并对光纤陀螺信号处理技术做了深入研究。首先,设计了三轴一体化的高精度光纤陀螺的光路结构,对光路中各个分立的光学器件建立基于琼斯矩阵的数学模型,根据光干涉理论和偏振态理论,建立了光纤陀螺整体光路的数学模型。在光路模型的基础上,分别仿真研究了集成光学相位调制器的消光比、光纤焊接熔接角、相位噪声以及光纤内部存在的偏振耦合点对干涉结果的影响。其次,详细分析了方波偏置下的数字闭环调制解调原理和反馈回路增益误差产生的原因及其解调方法,并对方波偏置下的数字双闭环调制解调方法的优缺点进行了深入的研究。在此基础上提出了基于四状态偏置的数字双闭环调制解调方案,分别研究了几种不同条件下的调制解调过程,并给出了调制解调方程。最后给出了四状态偏置的数字双闭环调制解调方案详细实现。再次,为了能够满足不同应用环境对光纤陀螺性能的要求、实现光纤陀螺系统参数的优化设计以及深入掌握光纤陀螺系统参数与光纤陀螺性能参数之间的关系,建立了光纤陀螺的数字双闭环控制回路模型,并进行仿真研究。对采用两种不同调制解调方案的光纤陀螺系统进行了实际比较,从而有效地证明了四状态偏置的数字双闭环调制解调方案的优越性,为提高光纤陀螺的精度提供了一个有效的途径。最后,为了减轻调制解调电路的压力,提高光纤陀螺的精度,提出了基于归一化最小均方算法(NLMS)的前向线性预测滤波器(FLP)的降噪方法。首先分析了光纤陀螺系统各种噪声的来源,并用Allan方差来描述,然后对FLP和NLMS理论进行了深入研究。最后对实时采集的光纤陀螺数据进行降噪处理,证明了基于NLMS的FLP降噪的有效性,为光纤陀螺精度的提高提供了又一个有效地途径。更多还原

【Abstract】 Over the past 30 years, as a new type of inertial-sensitive sensor, fiber-optic gyro (FOG)is widely used in the field of national defense. Abroad, with the arts of optical components and key technology of FOG were broken through, high-precision FOG has entered a stage of use. In China, as a result of the processing technology of optical components and some of the key technology is not yet broken through, high-precision FOG remains in the laboratory stage. Especially modeling techniques and signal processing technology of high-precision FOG, are still in the initial stages of exploration. In this article, based on the work of our predecessors, double closed-loop modem technology based on four-state is brought forward, the optical models and mathematical modeling on the closed-loop control circuit are in-depth research, and the signal processing technology of fiber-optic gyro is deeply studied.First of all, optical structure of three-axis integration fiber optic gyroscope is designed, and mathematical models of optical components in the optical circuit are modeled based on the Jones matrix, according to the theory of optical interference and polarization, the whole mathematical optical Model of FOG is established. On the basis of optical model, the effect of the integrated optical modulator extinction ratio,split ratio and the length of pigtail on the interferometer.Secondly, the modulation demodulation principle of digital closed-loop with the square-wave bias and the causation of gain error of feedback loop are detailed analysis, the advantage and disadvantage of digital double closed-loop modulation demodulation method are studied deeply. On this basis, the scheme of digital double closed-loop modulation demodulation with four-state-bias was brought forward, and the process of modulation demodulation under some different conditions were studied, and gave the modulate-demodulate equations. Finally, the realization of digital double-closed-loop with four-state bias was brought forward detailedly.Thirdly, in order to be able to meet the needs of different applications of fiber-optic gyro,and realize optimal design of parameters of fiber-optic gyro system,as well as master the relationship between the system parameters of FOG and performance parameters, established and simulated the digital double-closed-loop model of FOG. Comparison of two different modulate-demodulate scheme was made, and advantage of digital double closed-loop with four-state bias was proved effectively, and an effective route was brought forward to improve the accuracy of the FOG.Finally, in order to alleviate the pressure on the modulate-demodulate circuit, and improve the accuracy of FOG, noise reduction method of forward linear prediction filter (FLP) based on normalized least mean algorithm (NLMS). Firstly,all noise sources of FOG system was analysed, and their characteristics were described using the Allan variance, then made research deeply on the FLP and NLMS theories. At last, noise reduction was dealt with the real-time data of FOG, and the effectiveness of the FLP noise reduction based on FLP was proved, this provides another effective way to improve the accuracy of fiber optic gyroscope.更多还原