黑体空腔不等温性对辐射温度计校准结果影响的计算分析

针对常用的圆柱型无盖黑体空腔,分别计算了在对工作波长为单波长(1μm,1.6μm)、波段(3~5)μm、(8~14)μm的辐射温度计进行校准时,由于空腔的不等温性引起的积分发射率变化对校准结果造成的辐射温度偏差。计算结果表明,黑体空腔实际存在的不等温性引起的辐射光谱偏离理想黑体辐射对校准结果造成的偏差是不容忽略的,对于每一个具体的黑体辐射空腔,都要对其不等温对校准结果的影响予以考虑。     

基于非线性混合模型研究太空风化对月壤光谱的影响

月表太空风化会改变月壤光谱特征, 影响月壤元素遥感反演精度. 研究太空风化对月壤光谱的影响有助于开发月壤成熟度光谱解耦算法, 提高月壤成分遥感反演精度. 直接对比月壤风化前后光谱的变化能最真实反映太空风化对光谱的影响, 但无法获取未风化的月壤样品, 利用实验室模拟方法开展研究也存在缺陷. 本文提出了一种简便的方法来研究太空风化对月壤光谱的影响, 并以月海样品为例进行探讨. 利用Hapke模型对月海样品组成矿物光谱按照实测含量进行非线性混合, 并通过对比混合后的光谱与实测的月壤光谱, 研究太空风化过程对月壤光谱的影响. 研究结果表明, 月壤在遭受太空风化后反射率降低, 波长越短降低越显著; 月壤背景吸收斜率增大, 月壤变得更红, 月壤矿物特征吸收峰深度降低, 光谱对比度变弱, 长波吸收峰(2.0μm附近)深度降低程度超过短波吸收峰(1.0μm附近)深度. 未来在利用遥感技术反演月壤元素含量时, 必须考虑这些因素.      

主带彗星探测的科学目的及光谱仪设计构想

由于主带彗星富含水冰等挥发分并且位于火星与木星之间的小行星带区域,因此很可能是给早期地球带来水资源的天体,自从20世纪初期被发现以来引起了行星科学界的极大兴趣,是未来绕飞探测的重要候选目标。总结了主带彗星133P光谱探测的科学目标,并根据不同成分光谱特征分析和热特性研究需求,提出光谱仪的主要指标构想。谱段需覆盖可见至甚长波红外(0.4～50μm),通过可见红外成像光谱仪和热辐射光谱仪两台载荷分别覆盖0.4～5μm和5～50μm的波段范围。可见红外成像光谱仪采用紧凑型光栅分光系统设计,光谱分辨率在可见光谱段优于5 nm,红外谱段优于10 nm,5 km探测距离下空间分辨优于0.5 m,通过低温制冷抑制背景辐射噪声,保证信噪比优于100。热辐射光谱仪采用时间调制型干涉分光方案,由一台双角镜摆臂式干涉仪实现5～50μm的分光,光谱分辨率8 cm~(-1),5 km探测距离下空间分辨率优于10 m,采用非制冷热释电探测器。通过对两台光谱仪研制过程中涉及的关键技术进行分析,为后续开展工程研制奠定基础。     

海洋水色卫星的用途和特点

1　海洋水色探测原理□□众所周知 ,太阳入射至海洋表面的能量约占入射能的 3 0 % ,其余 70 %被大气吸收或散射后反射入太空。入射至海面的太阳能一部分被海面吸收或直接反射 ,另一部分透射进入水体。进入水体的太阳能光谱只有可见光 (0 .4 0 μm～ 0 .76μm) ,其中蓝光波段(0 .4 9μm)透水性能最好 ,如是清洁海水可透水几十米 ,其他波段透水性能远不如蓝光。透射入水的太阳能中一部分被水分子吸收 ,另一部分经水分子、浮游生物和悬浮颗粒等有机物质或无机物质散射 ,经散射后一部分离开水面反射出来 ,这部分反射能称为离水辐射能 ,对应的功…     

从地球观测-1卫星看21世纪卫星新技术

20 0 0年 11月 2 1日 ,美国 NASA发射了一颗崭新的卫星——地球观测 - 1(EO-1)卫星 ,其展示了 2 1世纪地球观测卫星的新概念和新技术。EO- 1卫星质量 46 0 kg,内装先进陆地成像仪 (AL I)、L EISA大气校正仪 (L AC)和高光谱成像仪(HYPERION)等 3台仪器。其中 AL I的用途和技术性能与 L ANDSAT- 7上的 ETM+相当 ;L AC用于测量大气水汽和气溶胶 ;HYPERION共有 2 2 0个波段 (0 .4μm～2 .5 μm范围内 ) ,30 m地面分辨率 ,用于地物波谱测量和成像、海洋水色要素测量以及大气水汽 /气溶胶 /云参数测量等 ,其性能比EOS Terra…     

基于太空风化的尖晶石二向性反射特性研究

简要介绍了不同太空风化条件下尖晶石的光谱特性,特别是利用Hapke模型计算了不同太空风化条件下尖晶石的二向性反射率分布特征。模拟的结果显示,对M3数据,可比较0.6μm和1.9μm附近的吸收特征;对IIM数据,则需要先分析太空风化程度,然后比较0.6μm和0.9μm附近的吸收特征来判断是否为尖晶石。该结论为选择探月传感器的波段组合识别尖晶石提供了依据,也为应用M3数据和"嫦娥1号"IIM数据的尖晶石判别奠定了基础。     

基于近场散射的颗粒粒径分布测量

针对传统的前向小角散射粒径测量系统中心光过强、杂散光干扰、散射角过小等缺点,本文采用一种新型的近场散射(NFS)方法测量前向小角散射光,研究并搭建了基于近场散射的颗粒粒径测量系统,将最大散射角提高到40.5°;在无需空白测量的情况下采用差分方法对透射光和散射光干涉成的散斑图像进行处理,有效去除中心光和杂散光的影响;对差分散斑图像进行快速傅里叶变换(FFT)频谱处理得到散射光强分布,利用Chahine算法对颗粒粒径进行了反演。最后,利用已知粒径(39.2μm和67.3μm)的标准颗粒对测量系统的准确性进行了单峰分布的验证,测量误差在5%之内;对于粒径为39.2μm和67.3μm的混合颗粒进行了双峰分布验证,在43.3μm和74.1μm处出现峰值,测量误差在10%左右。     

基于地物信息的高光谱遥感图像分类方法

利用主成分分析法滤除n维高光谱遥感图像中的大部分冗余信息,得到尽可能保留光谱信息的m维高光谱遥感图像,融合其地物空间分布信息,将m维高光谱遥感图像中的每一个像素点构建为一个2维谱-空信息向量。再利用主成分分析法法对m维高光谱遥感图像进行降维,得到q维融合地物空间分布信息与光谱信息的结果图。通过高斯混合模型预测聚类中心,基于改进的迭代自组织数据分析算法ISODATA(Iterative Selforganizing Data Analysis Techniques Algorithm)对高光谱遥感图像进行聚类,得到最终的分类结果。实验结果表明本方法的地物分类精度优于K-means、ISODATA和SVM方法,总体分类精度提升10.14%-13.99%,kappa系数提升3.2%-12.85%。     

印度发射高分辨率制图卫星-3

正2019年11月27日,印度制图卫星-3(Carto Sat-3)由印度"极轨卫星运载火箭"(PSLV-XL)发射升空。制图卫星-3是"制图卫星"系列的后续型号,采用IRS-2平台建造,是具有高分辨率成像功能的第三代敏捷卫星。印度空间研究组织(ISRO)称,该卫星将取代"印度遥感卫星"(IRS)系列。该星运行在高度509km、倾角97.5°的太阳同步轨道,发射质量1625kg,设计寿命5年。星上成像有效载荷全色模式地面分辨率0.25m,幅宽16km;四谱段多光谱模式分辨率1.13m,幅宽16km;高光谱模式分辨率12m。星上还载     

基于二氧化硅的微米级线距样片制备

设计了微米级线距样片的图形结构和制作工艺流程,制作了周期尺寸为(1～10)μm的线距样片。以周期尺寸为1μm和10μm的样片为例对样片的直线度、均匀性和稳定性等质量参数进行了考核。结果表明,研制的线距样片尺寸与设计值基本一致,稳定性好,与美国VLSI公司的标准样片进行了结果对比,本文研制的线距样片与VLSI的标准样片质量相当。     

Physical characteristics of the upper layers of Saturn's atmosphere

Analysis of polarimetric observations of Saturn was carried out. In the long wave-length spectral range (λ > 0.5μm) polarimetric observations do not contradict the model of spherical or irregular randomly oriented particles. In the short wave-length spectral interval (λ < 0.5μm) it is necessary to take into account the scattering by oriented particles.     

Mapping of hydrothermally altered rocks using airborne multispectral scanner data,Marysvale, Utah,mining district

Multispectral data covering an area near Marysvale, Utah, collected with the airborne National Aeronautics and Space Administration (NASA) 24-channel Bendix multispectral scanner, were analyzed to detect areas of hydrothermally altered, potentially mineralized rocks. Spectral bands were selected for analysis that approximate those of the Landsat 4 Thematic Mapper and which are diagnostic of the presence of hydrothermally derived products. Hydrothermally altered rocks, particularly volcanic rocks affected by solutions rich in sulfuric acid, are commonly characterized by concentrations of argillic minerals such as alunite and kaolinite. These minerals are important for identifying hydrothermally altered rocks in multispectral images because they have intense absorption bands centered near a wavelength of 2.2 μm. Unaltered volcanic rocks commonly do not contain these minerals and hence do not have the absorption bands.A color-composite image was constructed using the following spectral band ratios: 1.6μm/2.2μm, 1.6μm/0.48μm, and 0.67μm/1.0μm. The particular bands were chosen to emphasize the spectral contrasts that exist for argillic versus non-argillic rocks, limonitic versus nonlimonitic rocks, and rocks versus vegetation, respectively. The color-ratio composite successfully distinguished most types of altered rocks from unaltered rocks. Some previously unrecognized areas of hydrothermal alteration were mapped. The altered rocks included those having high alunite and/or kaolinite content, siliceous rocks containing some kaolinite, and ash-fall tuffs containing zeolitic minerals. The color-ratio-composite image allowed further division of these rocks into limonitic and nonlimonitic phases. The image did not allow separation of highly siliceous or hematitically altered rocks containing no clays or alunite from unaltered rocks.A color-coded density slice image of the 1.6μm/2.2μm band ratio allowed further discrimination among the altered units. Areas containing zeolites and some ash-fall tuffs containing montmorillonite were readily recognized on the color-coded density slice as having less intense 2.2-μm absorption than areas of highly altered rocks. The areas of most intense absorption, as depicted in the color-coded density slice, are dominated by highly altered rocks containing large amounts of alunite and kaolinite. These areas form an annulus, approximately 10 km in diameter, which surrounds a quartz monzonite intrusive body of Miocene age. The patterns of most intense alteration are interpreted as the remnants of paleohydrothermal convective cells set into motion during the emplacement of the central intrusive body.     

Infrared observations of contaminants from shuttle flight 51-F

A small helium cooled infrared telescope, IRT, was flown on the Shuttle in July/August 1985. The principle astrophysical objectives were to measure the large scale structure of sources and the background radiation. A cold shutter was incorporated to permit absolute flux measurements. Additionally, the engineering objectives included setting upper limits on the infrared radiation from the local environment. Even though the local background overwhelmed the astrophysical background, astronomical sources were still detectable superimposed on this background radiation. Data are presented covering the spectral range from 2μm to 120μm. The spatial, spectral and temporal variations are described. Based on the spectral character and variability in different wavelength bands, the background radiation does not appear to have a single origin. In this paper the results on the Shuttle environment will be presented. The astrophysical results will be presented elsewhere.     

量热技术在铷光谱灯中的应用研究

铷光谱灯是铷原子钟的核心部件。在铷光谱灯的研制中差式扫描量热技术（DSC）是不可或缺的测量手段和研究方法之一。本文通过对长期老化跟踪测量的铷量消耗数据拟合,得到了目前使用的铷灯的铷量消耗模型。分析结果显示：铷与灯泡内的杂质反应消耗了约37.5μg金属铷,铷的消耗率稳定在0.23μg/hr,预计10年使用寿命期内铷的消耗量约106μg。铷熔融曲线的熔点和纯度测量结果显示：铷的熔点和纯度在老化开始前2个月变化明显,具有较好的相关性。老化6个月以后铷的熔点和纯度从老化开始前的36℃和99.56％提高到39.5℃和99.84％,并趋于稳定,其变化趋势与老化初期铷量的消耗规律较好地吻合。     

CCD星敏感器光学系统设计

介绍ＣＣＤ星敏感器用光学系统设计的参数选择,光学系统的设计光谱范围０．４８、０．８５μｍ;焦距为７５ｍｍ,Ｆ／１．４４,视场８．５°。该系统为复杂化的Ｐｅｔｚｖａｌ结构形式;以点列图能量集中度和能量重心偏评价光学系统的成像质量。所选用的ＣＣＤ芯片像元尺寸为２３μｍ×２３μｍ,像元数３８４×２８８,全视场内混色光点列图能量重心偏最大值１．６μｍ,对应于４．３９角秒。     

Synergetic retrieval of terrestrial AOD from MODIS images of twin satellites Terra and Aqua

Aerosol optical depth (AOD) is one of the most important indicators of atmospheric pollution. It can be retrieved from satellite imagery using several established methods, such as the dark dense vegetation method and the deep blue algorithm. All of these methods require estimation of surface reflectance prior to retrieval, and are applicable to a certain pre-designated type of surface cover. Such limitations can be overcome by using a synergetic method of retrieval proposed in this study. This innovative method is based on the fact that the ratio K of surface reflectance at different angles/geometries is independent of wavelength as reported by Flowerdew and Haigh (1995). An atmospheric radiative transfer model was then established and resolved with the assistance of the ratio K obtained from two Moderate Resolution Imaging Spectroradiometer (MODIS) spectral bands acquired from the twin satellites of Terra and Aqua whose overpass is separated by three hours. This synergetic method of retrieval was tested with 20 pairs of MODIS images. The retrieved AOD was validated against the ground observed AOD at the Taihu station of the AErosol RObotic NETwork (AERONET). It is found that they are correlated with the observations at a coefficient of 0.828 at 0.47 μm and 0.921 at 0.66 μm wavelengths. The retrieved AOD has a mean relative error of 25.47% at 0.47 μm and 24.3% at 0.66 μm. Of the 20 samples, 15 and 17 fall within two standard error of the line based observed AOD data on the ground at the 0.47 μm and 0.66 μm, respectively. These results indicate that this synergetic method can be used to reliably retrieve AOD from the twin satellites MODIS images, namely Terra and Aqua. It is not necessary to determine surface reflectance first.     

基于EDT的扫描测试压缩电路优化方法

为了在集成电路可测试性设计（DFT）中实现更有效的测试向量压缩，减少测试数据容量和测试时间，采用嵌入式确定性测试（EDT）的扫描测试压缩方案分别对S13207、S15850、S38417和S38584基准电路进行了优化分析，通过研究测试向量和移位周期等影响测试压缩的因素，提出了固定测试端口和固定压缩率的扫描测试压缩电路优化方法。结果表明，在测试端口数量都为2，压缩率分别为12、14、16和24时具有较好的压缩效果，与传统自动测试向量生成（ATPG）相比，固定故障的测试数据容量减小了3.9~6.4倍，测试时间减少了3.8~6.2倍，跳变延时故障的测试数据容量减少了4.1~5.4倍，测试时间减少了3.8~5.2倍。所提方法通过改变测试端口数和压缩率的方式讨论了多种影响测试压缩的因素，给出扫描测试压缩电路的优化设计方案，提高了压缩效率，并对一个较大规模电路进行了仿真验证，可适用于集成电路的扫描测试压缩设计。      

Infrared astronomy on the Hubble Space Telescope

The Hubble Space Telescope offers enormous advantages to infrared astronomy in certain situations. The advantages of being above the atmosphere include an increase in spatial resolution, a much wider range of wavelengths available, and lower background radiation. Compared to proposed cooled telescopes, HST offers higher spatial resolution and increased collecting area. HST is particularly well suited to observations at wavelengths less than ～5 μm, where the diffraction limit is less than the seeing limit from the ground and thermal emission does not seriously compromise the sensitivity of the detectors. HST is also favorable for observations requiring high spectral resolution at all wavelengths not accessible from the ground.     

Extraction of hydrothermal alterations from ASTER SWIR data from east Zanjan,northern Iran

The use of satellite images for mineral exploration has been very successful in pointing out the presence of minerals such as smectite and kaolinite which are important in the identification of hydrothermal alterations. Shortwave infrared (SWIR) bands from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) with the wavelength of ASTER SWIR bands between 1.65 and 2.43 μm has a good potential for mapping a hydrothermal alteration minerals such as alunite, pyrophyllite, kaolinite, illite–muscovite–sericite, and carbonate. In this range, hydroxide minerals which have been produced by hydrothermal alteration exhibit good absorption compared to shorter or longer wavelengths. In this research which aims to remove atmospheric and topographic effects from ASTER SWIR data, the authors used the log-residual method (LRM) with the minimum noise fraction (MNF) transformation to create a pixel purity index (PPI) which was used to extract the most spectrally pure pixels from multispectral images. Spectral analyses of the clay mineralogy of the study area (east Zanjan, in northern Iran) were obtained by matching the unknown spectra of the purest pixels to the U.S. Geological Survey (USGS) mineral library. Three methods, spectral feature fitting (SFF), spectral angle mapping (SAM), and binary encoding (BE) were used to generate a score between 0 and 1, where a value of 1 indicates a perfect match showing the exact mineral type. In this way, it was possible to identify certain mineral classes, including chlorite, carbonate, calcite–dolomite–magnesite, kaolinite–smectite, alunite, and illite. In this research, two main propylitic and phyllic–argillic zones could be separated using their compositions of these minerals. These two alteration zones are important for porphyry copper deposits and gold mineralization in this part of Iran.