低成本光纤陀螺零相交信号处理

介绍光纤陀螺的低成本信号处理方案。此方案利用光纤陀螺输出信号的过零特性,把位相检测过渡为时域信号检测。     

光纤陀螺的信号处理方案评述

介绍了国外应用于不同场合、满足不同性能要求的光纤陀螺的闭环和开环信号处理方案,比较了它们的优缺点。光纤陀螺是近年来惯性导航系统中很有可能得到广泛应用的核心元件,其中信号处理方案在很大程度上决定了光纤陀螺的性能。     

电光相位调制器谐波响应对光纤陀螺的影响

从电光相位调制器的谐波响应出发,对干涉型光纤陀螺信号零偏、零漂的产生来源进行了探讨.用干涉理论和正弦波调制解调分析从原理上指出调制器的振幅与相位两种谐波可产生陀螺信号的零偏和零漂.根据调制器典型数据所做的模拟与人为加入温漂时所得的试验结果相当吻合.从而证实调制器谐波响应是产生陀螺信号偏移和漂移的主要原因,为减小光纤陀螺零偏和零漂提供了一条新思路.     

光纤陀螺仪零漂信号的Allan方差分析

介绍了光纤陀螺零漂实验的设备环境,硬件和软件的构成及数据采集过程。在测得光纤陀螺零漂信号的基础上,运用Allan方差理论对陀螺信号进行定量的分析,得到了光纤陀螺5个误差源系数的大小,并根据误差源的产生机理,找到了光纤陀螺硬件存在误差的部分,提出了光纤陀螺的改进方案。     

高准确度光纤陀螺中相位调制的控制研究

在相位调制器基础上，提出了围绕干涉型光纤陀螺的闭环控制方案.对高准确度光纤陀螺中Y波导集成光学器件的调制特性及系统测试方法进行了研究，对其应用及光路各环节配合的技术进行了探讨，对该器件在光纤陀螺系统中的特性和测试系统进行讨论.在高准确度光纤陀螺中取得明显效果.目前，工程样机的零偏稳定性已达到0.02°/h.     

单光纤光纤陀螺误差分析

单光纤光纤陀螺采用的是单光纤在线制作技术。由于这种方法是把所有的光器件都放在一根光纤上制作,因此各光器件的连接处没有融接点,并且光器件的性能可在线控制。在分析其结构的基础上建立了开环FOG的光学模型,并进行了误差分析。指出了单光纤光纤陀螺方案是低成本、高可靠性、易于工程化的一种方案。     

光纤陀螺温度补偿方案研究

从理论上分析了光纤陀螺敏感环的热致非互易相位噪声,建立了光纤环温度分布模型。针对四种通常的光纤敏感环绕制方法（ＺＹＬ,ＳＹＭ,ＤＩＰ,ＱＵＡ）对于由外界环境温度变动所引起的光纤陀螺零位漂移进行了数值模拟与比较,并给出了对应于外界环境温度变化过程中的光纤陀螺零位漂移补偿方案。     

单光纤光纤陀螺的原理及应用前景

单光纤光纤陀螺是全光纤光纤陀螺的一种,它具有低成本、高可靠性、易于工程化的优点。它是应用在线制作技术,在一根光纤上制作光器件,形成无焊接点的光路。在线技术包括光纤环缠绕技术、耦合器制作技术、偏振器制作技术、发光模块制作和光接收模块制作技术等。详细地介绍了其原理、关键技术及生产工艺,并提出了提高其性能的措施。在分析不同型号单光纤光纤陀螺性能的基础上展望了其应用前景。随着单光纤光纤陀螺生产工艺的改进和信号处理技术的提高,将会进一步提高其性能、降低成本,促进光纤陀螺的普及和应用。     

光纤陀螺中一种光相位差跟踪方法

对光纤陀螺中相位差的检测是得到所需角速度的基础。简要分析了陀螺输出信号的特点：噪声大、非线性、周期性,以及这些特点对检测有效信号的影响。提出了一种单通通光相位差跟踪的方法。这种方法采用正弦调制,通过对信号（包括输出信号和跟踪信号）的三角和乘法运算,并在必要的环节进行滤波得到光相位差。它能够解决光纤陀螺动态范围和刻度因子线性度问题,并具有简明、成本低、易实现的特点。最后进行了相位跟踪的计算机模拟和电路的实现,并给出了实验结果。     

PZT相位调制器温度漂移的控制

在光纤陀螺中,ＰＺＴ相位谳制器受温度变化影响会导致陀螺输出信号漂移。本文就这个问题提出一种解决方案,并通过实验进行验证。     

Analysis of BPSK homodyne receivers based on modified dither optical phase-locked loop

Optical homodyne receivers based on modified Dither Optical Phase-Locked Loop is analyzed taking into account the laser phase noise, photo detectors shot noise and the dither signal. This modified loop contains all the components of a standard Dither OPLL in conjunction of an additional phase modulator. This modified loop considerably improves the performance of the homodyne reception technique over the earlier technique with the help of commercially available external cavity lasers with line-width of about few hundred kHz. This modified dither OPLL seems a realistic approach for receiving modulated signal for inter-satellite communication systems. This modified technique provides the advantage of low weight, small size and above low cost because the proposed technique significantly reduces the requirement of very narrow line-width lasers. This modified dither loop shows good improvements in the reduction performance over previously reported methods, like, less system power penalty, relaxed line-width requirement.     

An innovation based random weighting estimation mechanism for denoising fiber optic gyro drift signal

In Interferometric Fiber Optic Gyroscope (IFOG), the diminution of random noise and drift error is a critical task. These errors degrade the performance of IFOG. In this paper, a modified adaptive Kalman gain correction (AKFG) algorithm is proposed to denoise IFOG signal. The covariance matrix of innovation sequence is estimated using weighted average window method in which the weights are randomly generated in the range [0, 1]. Innovation based random weighted estimation (IRWE)-AKFG is applied to denoise the IFOG drift signal. The Kalman gain is adaptively updated using the covariance matrix of innovation sequence. The proposed algorithm is applied for denoising IFOG signal under static and dynamic environment. Allan variance method is used to analyze and quantify the stochastic errors in IFOG sensor. The performance of the proposed algorithm is compared with Conventional Kalman filter (CKF) and the simulation results reveal that the proposed algorithm is an efficient algorithm for denoising the IFOG signal.     

Construction and characterization of interferometric fiber optic gyroscope (IFOG) with erbium doped fiber amplifier (EDFA)

Gyroscopes, which sense changes on absolute angular rate and are classified into Interferometric Fiber Optic Gyroscopes (IFOG), Ring Laser Gyroscopes (RLG) and Micro- Electro-Mechanical Systems (MEMS) Gyroscopes, are critical components of the navigation systems together with accelerometers. Being dominant over other types of gyroscopes in terms of performance and cost, IFOGs have widely been used in metrology and in particular defense/aerospace industry. This paper covers the design details of both optical and electronic components of IFOG prototype, the sensing mechanism of which is based on Sagnac Phase Shift, constructed in Optics Laboratory of National Metrology Institute of TURKEY as absolute angular rate sensor. In the prototype IFOG, open-loop configuration was applied, a single mode telecommunication optical fiber and an EDFA pumped by DFB laser emitting at 1549.0 nm were used as sensing coil and broadband source, respectively. The voltage data carrying Sagnac Phase Shift was extracted by a phase tracking circuit consisting of an active RC band pass filter, an amplifier with adjustable gain and an AD630 balanced modulator chip which was operated as lock-in. For the prototype IFOG, peak to peak noise of 8 (°/h) and bias stability of 1.57 (°/h) were attained respectively. Moreover the scale factor of 13.83 (°/h)/mV was derived with deviation of 0.73%.     

一种闭环式光纤加速度计设计

以光纤为挠性形变体、以激光为信息传递媒介,结合光电检测及闭环控制等技术设计了一种结构简单、成本低廉的光学加速度计,并就该方案实验系统各部件选型和系统测量灵敏度进行了简单分析。该方案可克服传统摆式光纤加速度计方案的不足,实现高精度和大动态范围的加速度测量。     

包含掺铒光纤和微结构光纤的光纤环镜光开关

设计了一种低开关功率的全光开关.将掺铒光纤和微结构光纤引入Sagnac环镜中,信号光在泵浦光作用下经过掺铒光纤被放大,破坏了环镜的平衡,利用交叉相位调制效应使两束反向传输的信号光产生非线性相移,实现了光开关效应.理论分析表明:信号光经过掺铒光纤后,增益越大微结构光纤的非线性系数越高,开关功率越低,并且环镜信号光的透射率随两束反向传输信号光的相移差成余弦变化.仿真得到开关功率约为26.73 mW,与理论分析一致.     

Coherent Beam Combination of Three Fiber Amplifiers with Multi-dithering Technique

Coherent beam combination of three W-level fiber amplifiers with multi-dithering technique is demonstrated. The multi-dithering technique is used for phase control in two channels. In the experiment, two channels are modulated by sine wave with 70 kHz and 100 kHz respectively, and two regular commercial DSP lock-in amplifiers and an industrial computer are used for electric signal processing in the feedback loop. The fringe contrast is advanced from 12% to 81%, and 78% coherent combination efficiency is obtained when the feedback loop is closed.     

A coherent beam combination system based on double PZT phase modulators

A novel coherent beam combination system based on double piezoelectric ceramics transducer (PZT) phase modulators is presented and demonstrated for the first time. In this system, two different PZT phase modulators are used for high frequency phase modulation and low frequency phase control, respectively, while in previous demonstrated system, LiNbO₃ phase modulators are often employed. The inherent low insert loss and high laser-induced damage threshold of the PZT phase modulator makes the new proposed system more compact and stable. By the way, the experiment of coherent beam combination of two 5-W fiber laser beams based on double PZT phase modulators is done. In the experiment, the PZT phase modulator with 500-kHz frequency response point made in home is used for high frequency phase modulating and another one with 0～30-kHz linear frequency response range for phase controlling. When the phase control system is in the closed loop, the fringe contrast of far-field intensity pattern is improved to be more than 90 % from 5 % in open loop.     

小型内窥镜干涉型光纤陀螺仪装配质量控制系统（英）

提出一种用于干涉型光纤陀螺仪(IFOG)装配质量控制的内窥镜系统设计及相关图像分析方法。同时采用1.0 mm与2.4 mm工业内窥镜系统采集IFOG内部图像与视频数据;并利用多自由度运动控制平台调节内窥镜工作姿态以保证图像的顺利采集。在此基础上,设计了基于db4小波基的图像增强方法,基于灰度共生矩阵的图像纹理特征估计方法以及图像几何形状特征的计算方法等,用以进行内窥镜图像的分析。通过上述系统与方法的应用,能够有效检测出IFOG产品在装配过程中出现的多余物颗粒、光纤断纤或异常胶粘等质量问题,有效提高了IFOG产品的装配质量。     

利用全光纤干涉解调技术的光纤光栅复用传感系统

提出了一种用于光纤光栅传感波长检测的新方法。系统采用全光纤Mach Zehnder干涉仪,运用动态的自参考相位检测方式,结合微机实时处理技术,实现了对三点复用传感器的高分辨率(0.99pm)解调,单点测量范围达3.32nm。系统结构简单、成本低,可以同时检测静态和低频动态信号。