开环Sagnac干涉仪的数字信号处理
发布时间：2019-05-06 20:55
【摘要】：Sagnac光纤干涉仪是一种典型的双光束光纤干涉仪,主要应用领域是干涉式光纤陀螺仪,其利用Sagnac效应来测量物体相对于惯性空间的旋转角速度。本学位论文主要对开环结构光纤陀螺仪的数字信号处理方法进行了研究。光纤陀螺仪的硬件包括光路和信号处理电路两个部分。论文描述了典型的开环光纤陀螺光路系统的组成,对主要光学器件的性能做了分析,并介绍了信号处理电路的详细设计过程,包括主要元器件的选型及工作原理。目前在开环陀螺的信号处理领域已经有多种解调方案被提出,论文对几种开环解调方案的实现过程做了总结。论文的核心是基于多次谐波的数字式开环光纤陀螺信号处理方案的设计,数字信号处理采用FPGA实现。由于光纤陀螺的光电探测器输出信号很微弱,因此在解调过程中采用锁定放大技术来进行微弱信号检测。论文的一个创新之处在于使用占用逻辑资源较少的CORDIC算法完成了信号处理中的调制正弦波产生、锁定放大器相敏检测和Sagnac相移解调等重要步骤。此外,调制深度控制和关键相位点的解调等工程应用中的实际问题也在论文中进行了详细讨论。由于数字信号处理过程中存在各种误差,论文对主要的几种误差来源进行了分析,重点讨论了相位调制器的非线性对陀螺零偏的影响。论文的另一个创新之处是提出了一种基于数字相位跟踪算法的新型开环光纤陀螺解调方案。实验结果如下：在常温条件下,开环光纤陀螺在-±200°/s的转速范围内的标度因数非线性度为818ppm,零偏为-10.60°/h,零偏不稳定性为0.046°/h,随机游走系数为0.008°/(?)。
[Abstract]:Sagnac fiber optic interferometer is a typical two-beam fiber optic interferometer. The main application field is interferometric fiber optic gyroscope, which uses Sagnac effect to measure the rotational angular velocity of objects relative to inertial space. In this thesis, the digital signal processing method of open-loop fiber optic gyroscope is studied. The hardware of fiber optic gyroscope consists of optical circuit and signal processing circuit. This paper describes the composition of the typical open-loop fiber optic gyroscope optical circuit system, analyzes the performance of the main optical devices, and introduces the detailed design process of the signal processing circuit, including the selection of the main components and the working principle. At present, many demodulation schemes have been proposed in the field of open loop gyro signal processing. The implementation of several open loop demodulation schemes is summarized in this paper. The core of this paper is the design of digital open-loop fiber optic gyroscope signal processing scheme based on multiple harmonics. The digital signal processing is realized by FPGA. Because the output signal of fiber optic gyroscope photodetector is very weak, lock-in amplification technique is used to detect weak signal in the demodulation process. One of the innovations of this paper is that the modulation sine wave generation in signal processing, the phase sensitivity detection of locking amplifier and the demodulation of Sagnac phase shift are accomplished by using CORDIC algorithm, which takes less logical resources. In addition, the practical problems in engineering applications, such as modulation depth control and demodulation of key phase points, are also discussed in detail in this paper. Because there are various kinds of errors in digital signal processing, the main error sources are analyzed in this paper, and the influence of nonlinearity of phase modulator on gyro bias is mainly discussed. Another innovation of this paper is to propose a new open-loop fiber optic gyroscope demodulation scheme based on digital phase tracking algorithm. The experimental results are as follows: at room temperature, the scale factor nonlinearity is 818ppm, the zero deviation is-10.60o / h and the zero bias instability is 0.046 掳/ h in the rotation speed range of-卤200 掳/ s for open-loop fiber optic gyroscopes. The random walk coefficient is 0.008 掳/ (?).
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TH744.3;TN911.72
本文编号：2470487
[Abstract]:Sagnac fiber optic interferometer is a typical two-beam fiber optic interferometer. The main application field is interferometric fiber optic gyroscope, which uses Sagnac effect to measure the rotational angular velocity of objects relative to inertial space. In this thesis, the digital signal processing method of open-loop fiber optic gyroscope is studied. The hardware of fiber optic gyroscope consists of optical circuit and signal processing circuit. This paper describes the composition of the typical open-loop fiber optic gyroscope optical circuit system, analyzes the performance of the main optical devices, and introduces the detailed design process of the signal processing circuit, including the selection of the main components and the working principle. At present, many demodulation schemes have been proposed in the field of open loop gyro signal processing. The implementation of several open loop demodulation schemes is summarized in this paper. The core of this paper is the design of digital open-loop fiber optic gyroscope signal processing scheme based on multiple harmonics. The digital signal processing is realized by FPGA. Because the output signal of fiber optic gyroscope photodetector is very weak, lock-in amplification technique is used to detect weak signal in the demodulation process. One of the innovations of this paper is that the modulation sine wave generation in signal processing, the phase sensitivity detection of locking amplifier and the demodulation of Sagnac phase shift are accomplished by using CORDIC algorithm, which takes less logical resources. In addition, the practical problems in engineering applications, such as modulation depth control and demodulation of key phase points, are also discussed in detail in this paper. Because there are various kinds of errors in digital signal processing, the main error sources are analyzed in this paper, and the influence of nonlinearity of phase modulator on gyro bias is mainly discussed. Another innovation of this paper is to propose a new open-loop fiber optic gyroscope demodulation scheme based on digital phase tracking algorithm. The experimental results are as follows: at room temperature, the scale factor nonlinearity is 818ppm, the zero deviation is-10.60o / h and the zero bias instability is 0.046 掳/ h in the rotation speed range of-卤200 掳/ s for open-loop fiber optic gyroscopes. The random walk coefficient is 0.008 掳/ (?).
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TH744.3;TN911.72
【参考文献】
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1 覃喜庆,曾祥鸿,董静,李平;基于ADN8830的高性能TEC控制电路[J];光学与光电技术;2004年01期
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