中高层大气风场探测多普勒非对称空间外差技术研究

发布时间：2018-06-24 23:12

本文选题：中高层大气 + 多普勒非对称空间外差干涉仪　；参考：《中国科学技术大学》2017年博士论文

【摘要】：中高层风场探测对于理解大气动力学和光化学过程,建立大气动态模型,提供中长期天气预报,保障航空航天事业的发展具有重要的作用。被动风场探测以中高层大气中的气辉为光源,通过谱线的多普勒效应反演风场参数。典型的被动风场探测技术包括Fabry-Perot干涉技术和Michelson干涉技术。近年来,多普勒非对称空间外差(Doppler Asymmetric Spatial Heterodyne,DASH)技术以其宽视场、大光通量、高光谱分辨率、静态干涉和多谱线同时探测的优点迅速成为被动风场探测的研究热点。结合空间外差光谱技术和Michelson干涉技术,通过大光程差处干涉相位的变化反演风速。国际上对DASH技术的研究已经有一定的基础,设计地基探测氧红线干涉仪。为了研制稳定性较高的仪器,采用Koster棱镜分光形成共光路单臂式干涉仪结构,增大系统的光程差要以成倍增加仪器体积为代价,因此在星载仪器设计时采用了双臂式方案。另一方面,风速通过干涉绝对相位差分获得,具有抗干扰能力强的特点,目前的风速反演并没有考虑相位计算过程中的数据处理误差,然而低相位灵敏度和数据处理误差两方面均影响了实际的风场探测精度。基于以上考虑,本文研制了双臂大光程差DASH干涉仪LODI(Large Offset DASH Interferometer,LODI),通过设计风速模拟器并搭建实验平台实现风场模拟探测。在数据处理过程中,提出窗函数参数的优化选择方法和相位漂移校正方法,实现干涉数据的误差修正,提高风速反演精度。本论文的主要工作包括以下几个方面:1.基于DASH技术的风场探测机理研究。从探测目标的选择出发,阐述了探测目标的性质和对干涉仪系统设计的要求。在DASH理论模型的基础上,针对风场探测需求对干涉仪关键指标进行理论分析和推导,明确系统参数设计的理论依据。2.依据DASH干涉仪基本原理提出LODI的仪器参数,进行系统仿真分析和设计。对干涉仪光学元件误差(分束器、扩视场棱镜、光栅等)、系统噪声和环境变化等因素产生的基频漂移、绝对相位误差和风速误差进行了仿真和定量分析;根据干涉仪的探测需求,参考性能指标设计系统的详细参数。3.基于DASH技术的风场反演算法研究。通过对比分析傅里叶级数法和傅里叶变换法求解干涉相位的优劣,得出后者更适合应用在DASH干涉相位获取。在确定相位算法的前提下,对数据处理中的误差进行分析,指出窗函数作为一个外部变量,是引起干涉数据误差的原因。提出窗函数优化选择方法,指出通过选择半高宽为2的Nuttall窗,能够使由窗函数参数产生的风速误差最小化。4.LODI风场探测实验研究。根据风速模拟基本原理,给出风速模拟器的机械设计方案,并且定量分析了风速模拟器的模拟风速误差,指出总风速模拟误差约为1.3%,主要是由夹角误差和测量误差导致。以干涉仪系统为核心搭建试验装置进行风速模拟探测,对干涉数据进行误差修正。通过在光谱变换时进行窗函数优化分析,指出在光程差间隔内矩形窗产生的风速误差达1.75m/s,Nuttall窗下的风速变化最小,约0.75m/s。随着窗函数半高宽增加,风速误差变大。选择半高宽为2的Nuttall窗函数,使在风速47.62 m/s时的风速误差减小了约1.5 m/s。通过测量多组同一风速下的干涉图频移,反演得到风速误差为6.1 m/s,该误差主要来源于相位漂移。为了消除相位漂移误差对风速的影响,通过连续采样的方法进行相位漂移误差校正,风速误差在校正后降低了 28 m/s,从而实现测量精度的提高。在34.19 m/s到78.63 m/s范围内进行24组风速模拟探测实验,得出相应的风速反演误差和不确定性,最终获得2.92m/s的实验室风速模拟探测精度。
[Abstract]:Middle and high rise wind field detection plays an important role in understanding atmospheric dynamics and photochemical processes, establishing atmospheric dynamic models, providing medium and long term weather forecasting, and ensuring the development of Aeronautics and Astronautics. The passive wind field detection uses the air glow in the middle and upper atmosphere as the light source and the Doppler effect of the spectral line is used to retrieve the wind field parameters. Wind field detection techniques include Fabry-Perot interferometry and Michelson interferometry. In recent years, Doppler asymmetric spatial heterodyne (Doppler Asymmetric Spatial Heterodyne, DASH) technology has rapidly become the research heat of passive wind field detection with its wide field of view, large light flux, high spectral resolution, static interference and simultaneous detection of multispectral lines. In combination with spatial heterodyne spectroscopy and Michelson interference technique, the wind velocity is retrieved through the variation of interference phase in the large optical path difference. The research on DASH technology has already had a certain foundation, and the oxygen and red line interferometer is designed for the foundation detection. In order to develop the instrument with high stability, the Koster prism is used to form the single arm interference of the common optical path. At the expense of increasing the optical path difference of the system, the dual arm scheme is used in the design of the spaceborne instrument. On the other hand, the wind speed is obtained by interfering with the absolute phase difference. The wind speed inversion does not take into account the data processing error in the phase calculation. However, the two aspects of low phase sensitivity and data processing error all affect the accuracy of the actual wind field detection. Based on the above considerations, this paper developed a double arm large optical range DASH interferometer LODI (Large Offset DASH Interferometer, LODI). By designing the wind speed simulator and building an experimental platform to realize the wind field simulation detection. In the data processing process, the data processing process is realized. In this paper, the optimal selection method of window function parameters and the phase drift correction method are proposed to correct the error of interference data and improve the accuracy of wind velocity inversion. The main work of this thesis includes the following aspects: 1. research on the mechanism of wind field detection based on DASH technology. On the basis of the DASH theoretical model, the theoretical analysis and deduction of the key indexes of the interferometer are carried out on the basis of the requirement of the wind field detection. The theory of system parameter design is made clear by.2. based on the basic principle of DASH interferometer. The system simulation analysis and design are carried out. The error of the interferometer optical element is analyzed and designed. (beam splitter, field prism, grating, etc.), fundamental frequency drift, absolute phase error and wind speed error caused by system noise and environmental change, and the detailed analysis of the absolute phase error and wind speed error. According to the detection requirements of the interferometer, the detailed parameters of the reference performance index design system.3. based on the DASH technique are studied. This paper analyzes the advantages and disadvantages of Fu Liye series method and Fu Liye transform method to solve the interference phase, and concludes that the latter is more suitable for DASH interference phase acquisition. On the premise of determining the phase algorithm, the error in the data processing is analyzed. It is pointed out that the window function is an external variable, which is the cause of the interference data error. It is pointed out that by selecting a Nuttall window with a half width of 2, the wind speed error generated by the window function parameters can be minimized by the.4.LODI wind field detection experiment. According to the basic principle of the wind speed simulation, the mechanical design scheme of the wind speed simulator is given, and the simulated wind speed error of the wind speed simulator is quantitatively analyzed, and the total wind speed simulation is pointed out. The error is about 1.3%, which is mainly caused by the angle error and the measurement error. The wind speed simulation detection is built with the interferometer system as the core. The error correction is made to the interference data. Through the window function optimization analysis in the spectral transformation, the wind speed error generated by the moment window in the gap interval of the optical path is 1.75m/s, Nuttall window. The wind speed change is minimal, and the wind speed error becomes larger with the increase of the half height and width of the window function, and the wind speed error becomes larger. Select the Nuttall window function of half Gao Kuan 2. The wind speed error at 47.62 m/s is reduced by about 1.5 m/s. by measuring the frequency shift of the interferogram under the same wind speed, and the wind velocity error is 6.1 m/s, which is mainly derived from the phase. Position drift. In order to eliminate the influence of phase drift error on wind speed, the phase drift error correction is carried out by continuous sampling method. The wind speed error is reduced by 28 m/s after correction, thus the measurement accuracy is improved. 24 sets of wind speed simulation experiments are carried out in the range of 34.19 m/s to 78.63 m/s, and the corresponding wind velocity inversion error is obtained. Uncertainty, and ultimately obtain the accuracy of 2.92m/s laboratory wind speed simulation.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：P412.2

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