光纤干涉信号的数字处理方法的研究

发布时间：2018-01-07 14:21

本文关键词：光纤干涉信号的数字处理方法的研究　出处：《浙江大学》2014年硕士论文　论文类型：学位论文

【摘要】：光纤双光束干涉信号的数字处理方法研究主要针对Sagnac干涉仪,即干涉式光纤陀螺(Interferometric Fiber Optic Gyro, IFOG),其常用作为高精度的惯性角速度传感器,在导航和制导领域占据重要的地位。本文第一部分主要介绍基于FPGA的开环光纤陀螺的数字系统设计方法的研究。相比于传统的模拟开环检测电路,数字开环检测系统具有更好的稳定性、高集成度的体积以及较强的抗干扰能力等优点。针对大多数DSP开环检测方案,本文提出了一种基于CORDIC算法及微弱信号检测原理,以FPGA为数字核心运算单元,实现调制正弦波的产生以及各次谐波信号的解调。最终实现干涉信号的一次谐波、二次谐波以及四次谐波的解调输出。本文第二部分重点对数字闭环光纤陀螺干涉信号的数字检测系统作了研究。首先介绍陀螺的系统结构,以及其相关误差机理分析。闭环数字检测系统采用传统的方波调制解调以及阶梯波反馈方案。介于已有的A/D转换器+FPGA以及A/D+CPLD+DSP为核心的检测方案,本设计将采用ADI公司高度集成化的ADSP-21992芯片做高速采样及信号处理。将干涉产生的Sagnac旋转相移φs通过ADSP芯片的A/D转换器控制端高速采样送入DSP数字处理模块,得到相位的误差信息并通过积分反馈控制形成阶梯波反馈相位φf,抵消其产生的Sagnac相移。将方波调制信号叠加至反馈阶梯波一起通过反馈通道施加到相位调制器(LiNbO3)上,从而实现第一闭环反馈。同时,为了修正2π电压随温度漂移引起的误差,通过第二闭环反馈控制来调节LiNbO3的2π复位电压。最终通过ADSP的同步串行口SPORT实现与上位机的数据传输。该系统的实验结果主要包括零偏为-7.29°/h(包含当地自转-7.56°/h),零偏稳定性约为0.012°/h,随机游走系数为0.0045°/(?)h,标度因素非线性度为3.88ppm。
[Abstract]:The digital processing method of optical fiber dual-beam interference signal is mainly focused on the Sagnac interferometer. The Interferometric Fiber Optic Gyro (IFOG) is commonly used as an inertial angular velocity sensor with high precision. It plays an important role in the field of navigation and guidance. The first part of this paper mainly introduces the design method of digital system of open-loop fiber optic gyroscope based on FPGA. Compared with the traditional analog open-loop detection circuit, the digital open-loop detection system has better stability. For most DSP open-loop detection schemes, this paper proposes a new method based on CORDIC algorithm and weak signal detection principle. Using FPGA as the digital core operation unit, the generation of modulated sine wave and demodulation of each harmonic signal are realized, and the demodulation output of the first harmonic, the second harmonic and the fourth harmonic of the interference signal is finally realized. The second part of this paper focuses on the digital detection system of the digital closed loop fiber optic gyro interference signal. Firstly, the structure of the gyro system is introduced. The closed-loop digital detection system adopts the traditional square wave modulation and demodulation and step wave feedback scheme. It is between the existing A / D converter FPGA and the A / D CPLD. DSP is the core detection scheme. In this design, the highly integrated ADSP-21992 chip of ADI company will be used for high speed sampling and signal processing. The Sagnac rotation phase shift 蠁 s produced by interference will be passed through the A / D of ADSP chip. High speed sampling at the control end of the converter is fed into the DSP digital processing module. The error information of the phase is obtained and the step wave feedback phase 蠁 f is formed by integral feedback control. The square wave modulation signal is superimposed on the feedback ladder wave to be applied to the phase modulator Linbo _ 3 through the feedback channel, thus realizing the first closed-loop feedback. At the same time. In order to correct the error caused by the temperature drift of 2 蟺 voltage. The 2 蟺 reset voltage of LiNbO3 is adjusted by the second closed-loop feedback control. Finally, the data transmission to the host computer is realized through the synchronous serial port SPORT of ADSP. The experimental results of the system mainly include. The bias is -7.29 掳/ h (. Including local rotation-7.56 掳/ h). The zero bias stability is about 0.012 掳/ h, and the random walk coefficient is 0.0045 掳/ r? The nonlinearity of the scale factor is 3.88 ppm.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN911.7

【参考文献】