| 题名 | 基于低平流层激光测风雷达的光学鉴频器精密温控与光谱标定技术研究 |
| 作者 | 赵存峰 |
| 文献子类 | 硕士 |
| 导师 | 陈卫标 |
| 关键词 | 激光测风雷达 Wind Lidar 光学鉴频器 Optical discriminator 温度 Temperature 光谱标定 Spectral calibration |
| 其他题名 | Research on Precise Temperature Control of Optical Discriminators and Spectral Calibration Technology based on Low Stratospheric Wind Lidar |
| 英文摘要 | 激光测风雷达是目前唯一能够获取地面到低平流层三维风场的遥感手段，它主要应用在大气动力学、气象、气候预报和科学研究等领域。激光测风雷达主要分为两种：一种是直接探测激光测风雷达，主要探测目标为分子；另外一种是相干探测激光测风雷达，主要探测目标为气溶胶。直接探测激光测风雷达以其直接探测分子的平均运动速度而得名，因此它是探测低平流层风场的最重要手段。本文中所用的光学鉴频器是基于Fabry-Perot的光学干涉仪，采用两个干涉通道形成双边缘检测，将回波信号的多普勒频移量转化为能量变化，最后根据探测到的信号变化解算出多普勒频移和风速。该光学鉴频器光学平面度和平行度极高：例如光学鉴频器平面度峰谷值（PV）达到百分之一波长，环境参量改变易造成精细度恶化，腔长对温度参量敏感易造成透过率曲线漂移等，因此需要对鉴频器进行精密控制和光谱标定以解决使用过程不稳定的问题，这也是当前基于Fabry-Perot直接探测激光测风雷达发展较早但一直未有可靠运行的产品出现的技术瓶颈之一。基于此本论文着重研究了鉴频器的精密温控，透过率曲线的精密标定等内容，具体如下： 本论文主要研究工作如下： （1）鉴频器的温度精密测量和控制：F-P鉴频器对温度环境十分敏感，为了解决温度变化对鉴频器的影响，本论文设计一种实现鉴频器高精度温度控制方案,采用弱电流双路方向可切换的电流源驱动方案,显著减小了自热效应、器件温漂,消除了电流源匹配误差。采用基于数字和模拟混合控制技术提高了测量精度,实验结果表明,在30℃到50℃范围内温度测量误差为0.0036℃，温度控制精度为0.0062℃。该控制精度对鉴频器的影响为频率移动0.11 MHz,对应速度测量误差为0.0195 m/s。 （2）单频紫外激光器产生的355 nm的激光作为激光测风雷达光源，需要实现光信号到电信号的转换和激光能量的采集。单频紫外激光器脉冲宽度为6 ns，本论文设计了一种能实现光电转换的积分电路。经过实验，激光信号经过该积分电路后，得到电信号的宽度为250 us，从而激光能量能够轻松为后续模数转换电路采集。 （3）基于F-P鉴频器透过率曲线的精确标定的技术。本论文设计了一套用于鉴频器光谱标定的子系统。利用激光注入F-P鉴频器并进行鉴频器曲线的扫频和标定，通过自主设计积分电路、基于FPGA的扫频控制电路、采集电路，通过数据处理，实测两个探测通道的透过率谱线，标定出实测灵敏度曲线。解决由于F-P鉴频器在运行过程中的环境蠕变，导致光谱的移动以及测量误差。经过实验，获取了鉴频器透过光谱标定数据和测量灵敏度的标定数据等。实验结果表明：当风速为1 m/s时，标定后的数据可以将风速误差降低0.4186 m/s，当风速为10 m/s时，标定后的数据可以校正掉2.7614 m/s风速误差。 本论文的工作内容重点在于对F-P光学鉴频器的温控技术和标定技术，为该鉴频器的实用化提供了解决思路，研究成果应用于低平流层激光测风雷达系统。; Wind lidar is currently the only remote sensing method that can obtain three-dimensional wind field from the ground to the low stratosphere. It is mainly used in the field of atmospheric dynamics, meteorology, climate forecasting and scientific research. Wind lidar is mainly divided into two types: one is direct detection wind lidar, the main detection target is a molecule; the other is a coherent detection wind lidar, the main detection target is aerosol. The direct detection wind lidar is named after its direct detection of the average molecular moving speed, so it is the most important means to detect the low stratospheric wind field. The optical frequency discriminator used in this article is a Fabry-Perot based optical interferometer. Two interferometric channels are used to form dual-edge detection. The Doppler shift of the echo signal is converted into energy change. Finally, the detected signal is used. The variation resolves the Doppler frequency and wind speed. The optical discriminator has extremely high optical flatness and parallelism：for example, when the optical discriminator flatness value (PV) reaches a one-hundredth of a wavelength, the change of the environmental parameter may cause the deterioration of the fineness, and the cavity length is sensitive to the temperature parameter and may easily cause a shift in the transmittance curve. Therefore, precise detection and spectral calibration of the frequency discriminator are needed to solve the problem of unstable operation. This is also one of the technical bottlenecks that have been present in Fabry-Perot's direct detection of laser wind-gauge radars, but have not been reliably operated. Based on this paper, we focused on the precise temperature control of the discriminator, precision calibration of the transmittance curve, and so on, as follows: The main research work of this paper is as follows: (1) Accurate temperature measurement and control of discriminator: F-P discriminator is very sensitive to temperature environment. In order to solve the influence of temperature change on discriminator, this paper designs a method to realize high precision temperature control of discriminator. The use of a weak current dual-direction switchable current source driving scheme significantly reduces self-heating effects, device temperature drift, and eliminates current source matching errors. Using digital and analog based hybrid control techniques to improve the measurement accuracy, the experimental results show that the temperature measurement error in the range of 30 to 50 °C is 0.0036 °C, and the temperature control accuracy is 0.0062 °C. The effect of this control accuracy on the frequency discriminator is that the frequency shift is 0.11 MHz, and the corresponding speed measurement error is 0.0195 m/s. (2) The 355 nm laser generated by a single-frequency ultraviolet laser is used as wind lidar source, and it is necessary to convert the optical signal into an electric signal and laser energy collection. The pulse width of single-frequency ultraviolet laser is 6 ns. In this paper, an integrated circuit which can realize photoelectric conversion is designed. After the experiment, the laser signal passes through the integrator circuit and the width of the electrical signal is 250 us, so that the laser energy can be easily acquired by the subsequent analog-to-digital conversion circuit. (3) Based on the F-P discriminator transmittance curve accurate calibration technology. This paper designs a set of subsystems for discriminator spectral calibration. Using laser to inject F-P discriminator and frequency sweeping and calibration of discriminator frequency curve, through the independent design of integral circuit, FPGA-based swept frequency control circuit, and acquisition circuit, through data processing, actually measure the transmittance spectrum of the two detection channels and calibrate the measured sensitivity curve. Solve the environmental creep of the F-P discriminator during operation, resulting in spectral shifts and measurement errors. Through experiments, spectral calibration data such as spectral calibration data and measurement sensitivity calibration data were obtained. The experimental results show that when the wind speed is 1m/s, the calibrated data can reduce the wind speed error by 0.4186 m/s. When the wind speed is 10m/s, the calibrated data can correct 2.7614 m/s wind speed error. The focus of this dissertation is on the temperature control technology and calibration technology of the F-P optical discriminator, which provides a solution to the practical application of the discriminator. The research results are applied to the low stratospheric laser wind radar system. |
| 学科主题 | 光学工程 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/31115]  |
| 专题 | 中国科学院上海光学精密机械研究所 |
| 作者单位 | 中国科学院上海光学精密机械研究所 |
| 推荐引用方式 GB/T 7714 | 赵存峰. 基于低平流层激光测风雷达的光学鉴频器精密温控与光谱标定技术研究[D]. |
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