月球纵向温度分布遥感探测方法研究

发布时间：2018-03-31 09:22

本文选题：月球　切入点：温度　出处：《华中科技大学》2016年博士论文

【摘要】：月球是深空探测的起点,它可以为人类提供丰富的资源,对月球进行探测不仅可以利用这些资源并且还可以了解月球演化史,为人类进一步了解宇宙提供更多宝贵信息。月表纵向温度分布是探月的科学目标之一,通过它不仅可以得到月球热流信息,还可以提取古太阳辐射的历史信息,揭示古太阳辐射变化规律。古太阳辐射变化规律可以作为分析太阳辐射对地球气候影响的重要依据,对研究地球全球气候变化问题具有重要的意义。本文研究月表纵向温度分布的遥感探测方法,首先建立了月表的微波辐射和散射模型;然后根据实测数据,分析了月球永久阴影区的亮温分布特征。为了实现月表纵向温度分布探测的目标,重点讨论了如何利用多频微波辐射亮温进行温度剖面的反演。最后,搭建了散射测量系统并设计了用于散射测量的天线,在微波暗室对模拟月壤结构进行了散射测量。本文的研究工作主要包括以下几个内容:为了了解月表的微波辐射和散射特性,需要建立辐射和散射模型。本文首先提出了一种改进的IEM2Mc方法,用于计算粗糙月表的电磁散射问题,该方法主要特点在于在基尔霍夫表面场项中保留了完整的表面电流项和采用过渡模型来预测菲涅尔反射系数,在入射角或者散射角偏大时可以更好地估计散射系数。计算结果显示,当散射角大于60度后,改进和未改进前的结果差别会越来越大。将改进的IEM2Mc方法和非相干方法进行混合,用于计算月表多层结构的微波辐射亮温,表面的发射率通过改进的IEM2Mc方法得到,表面下的多层结构的辐射亮温则由非相干方法得到。此外,还利用非相干方法建立了多层模型用于分析辐射计埋入月壤内时辐射计上部物质辐射亮温与辐射计接收到的总亮温的关系,仿真的结果显示在零度角时上部的辐射贡献极其小。利用嫦娥二号的微波亮温数据和LRO探测器的红外亮温数据,分析了月球南极永久阴影区Shoemaker、Haworth撞击坑的微波和红外亮温分布规律,发现永久阴影区内微波和红外亮温随时间变化不一致的现象,即红外亮温会随时间持续降低,而微波亮温则在2011年3月后下降变缓甚至有上升趋势。随后,利用热传导模型和微波辐射模型解释了这一异常现象,同时利用假设的线性温度函数对Shoemaker地区进行了温度剖面反演,发现线性温度函数并不能解释永久阴影区全年的变化情况。当遥感设备位于月表上时,从辐射计探测深度的两种定义方式出发,分别计算了探测10米以上温度信息所需要的探测频率,并进一步给出内部极小温度波动时,对应所需的辐射计灵敏度。利用微波辐射模型计算了多频反演时的权值函数,采用先验约束法对月表纵向温度剖面进行了反演,反演时分别考虑了微波辐射计置于月表上方和埋入月壤内部时两种情况,结果显示埋入月壤内部时反演的效果更好。搭建了频率步进的散射测量系统并设计了用于散射测量的天线,设计的天线是准八木结构的微带天线,可以工作在两个频段。天线可以组成天线阵,在阵列中天线之间引入蛇形细槽结构以降低互耦。将天线与矢量网络分析仪组成频率步进的微波散射测量系统,并利用该系统的测量数据计算出模拟月壤的介电常数,进一步验证了天线性能和散射计测量系统的可行性,同时说明散射测量可以给纵向温度探测提供介电常数和月壤内部结构信息。
[Abstract]:The moon is the starting point of deep space exploration, it can provide rich resources for mankind, lunar detection can not only can understand the evolution and use of these resources, provide more valuable information for further human understanding of the universe. The lunar surface longitudinal temperature distribution is one of the scientific objectives of the moon, it can not only get the moon through the heat flow information. You can also extract the ancient solar radiation history information, reveal the variation of solar radiation. The solar radiation variation can be used as an important basis for the analysis of solar radiation of the earth's climate, has important significance to study the earth's global climate change. The research of lunar remote sensing detection method of longitudinal temperature distribution, firstly microwave radiation and scattering model the table was set up; then according to the measured data, analysis of the brightness temperature distribution characteristics of the permanently shadowed area. In order to achieve The lunar surface longitudinal temperature distribution detection target, discussed how to use the inversion of multi frequency microwave radiation temperature profile. Finally, build a measurement system for antenna scattering and scattering measurement is designed, in the microwave darkroom and simulated lunar soil structure by scattering measurements. The main research work of this paper includes the following contents in order to understand the lunar surface microwave radiation and scattering characteristics, need to establish radiation and scattering model. This paper proposes an improved IEM2Mc method for calculating electromagnetic scattering problems of rough surface, the main method is characterized in that the Kirchhoff surface field in retaining the integrity of the surface current and the transition model to predict Finel the reflection coefficient, when the incident angle or angle scattering can better estimate the scattering coefficient. The calculation results show that when the scattering angle is greater than 60 degrees, and improvement Improve the difference between the results will be more and more. The improved IEM2Mc method and a non coherent mixing method, used to calculate the brightness temperature of lunar surface microwave radiation multilayer structure, surface emissivity by improved IEM2Mc method, radiation multilayer structure under the surface brightness temperature by non coherent method. In addition, also the use of non coherent method to establish the multi-layer model is used to analyze the relationship between the total radiation brightness temperature meter upper material radiation brightness temperature and radiation received by the radiometer embedded within the lunar soil, the simulation results show that the contribution of radiation in the upper part of the zero angle is extremely small. The infrared brightness temperature data and LRO detector using microwave Chang'e two the brightness temperature data, analysis of the Shoemaker pole of the moon permanently shadowed craters, microwave and infrared Haworth brightness temperature distribution, found permanent in the shadow areas of microwave and infrared brightness temperature changes with time inconsistent The phenomenon, namely the infrared brightness temperature will continue to decrease over time, while the microwave brightness temperature in March 2011 after falling slowly even rise. Then, using the model of radiation heat conduction model and microwave to explain this abnormal phenomenon, at the same time using the linear function of temperature on the Shoemaker region of the assumed temperature profile inversion, linear the temperature function does not explain the changes of annual permanent shadow area. When the remote sensing equipment located on the lunar surface, starting from the two kind of definition of radiometer detection depth, detection frequency detection of 10 meters above the temperature required information are calculated respectively, and further gives the minimum internal temperature fluctuation, radiation corresponding to the required sensitivity the weight function. Multi frequency inversion calculation using microwave radiation model, using a priori constraint method for the inversion of surface longitudinal temperature profile inversion are considered micro Wave radiometer in lunar regolith above and buried inside the two case, the results show better effects in lunar internal inversion. Scattering measurement system is built step frequency and designed for antenna scattering measurement, design of antenna structure is quasi Yagi microstrip antenna, can work in two frequency bands the antenna can be. Antenna array composed of serpentine cannelure structure is introduced between the array antenna to reduce mutual coupling. The microwave scattering measurement system of the antenna and the Vector Network Analyzer composition step frequency, and calculate the dielectric constant of quasi mode of lunar regolith based on measurement data of the system, in order to verify the feasibility of the performance of the antenna and scattering. The measurement system, and explain the scattering measurements can give the longitudinal temperature detection of dielectric constant and regolith internal structure information.

【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：P184.5

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