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21.
红外探测阵列对固体导弹尾焰跟踪定位的研究 总被引:2,自引:0,他引:2
通过分析研究建立了前视红外探测阵列FLIR(Forward Looking Infra-Red)对导弹进行精确跟踪、定位的数学模型,其中包括导弹的运动模型、大气干扰模型和探测阵列的观测模型。利用探测阵列FLIR的原始观测数据,扩展卡尔曼滤波器(EKF)精确跟踪导弹目标。由于导弹与探测器的距离较远,故为视为点目标。导弹在探测阵列上投影的位置由两部分组成:导弹真实运动位置和由于大气干扰造成的偏移。滤波 相似文献
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提高航天传输型CCD相机地面像元分辨率方法研究 总被引:5,自引:1,他引:5
文章首先对空间传输型遥感相机提高像元分辨率的几种常规和非常规方法做了简介,在分析这些方法的优缺点以及以采样定理为依据分析我国现有CCD相机光学截止频率和CCD采样频率存在的矛盾的基础上探讨了高模式采样技术和超模式采样技术,经过比较这两种采样模式,认为超模式采样技术更具有工程可行性和优越性。然后对超模式采样计算机图像仿真结果进行了分析。 相似文献
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测试了IMI834高温钛合金在600~750℃的空气中热暴露100小时后拉伸性能,利用透射电镜和扫描电镜观察了合金暴露前后的组织变化及拉伸断口,认为表面氧化是造成合金热暴露后塑性下降的主要原因,但基体组织内有序α2相和硅化物的析出变化也在不同程度上造居了合金热暴露后的强度和塑性的下降。 相似文献
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基于应力传递的剪滞理论,详细分析推导了纤维中的残余热正应力和界面层中的剪应力解析公式,并与已有的理论公式进行了比较。同时分析了纤维与基体脱粘的原因及热残余应力主要影响因素,主要包括:纤维和界面层材料的弹性模量,界面层的厚度以及纤维的长径比等。通过分析得出:纤维中的压应力和界面层中的剪应力都随着界面层的厚度及其弹性模量的增大而增大;纤维长径比的大小对纤维中的压应力和界面层中的剪应力大小及分布的影响很小。 相似文献
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S. M. Krimigis D. G. Mitchell D. C. Hamilton S. Livi J. Dandouras S. Jaskulek T. P. Armstrong J. D. Boldt A. F. Cheng G. Gloeckler J. R. Hayes K. C. Hsieh W.-H. Ip E. P. Keath E. Kirsch N. Krupp L. J. Lanzerotti R. Lundgren B. H. Mauk R. W. McEntire E. C. Roelof C. E. Schlemm B. E. Tossman B. Wilken D. J. Williams 《Space Science Reviews》2004,114(1-4):233-329
The magnetospheric imaging instrument (MIMI) is a neutral and charged particle detection system on the Cassini orbiter spacecraft designed to perform both global imaging and in-situ measurements to study the overall configuration and dynamics of Saturn’s magnetosphere and its interactions with the solar wind, Saturn’s atmosphere, Titan, and the icy satellites. The processes responsible for Saturn’s aurora will be investigated; a search will be performed for substorms at Saturn; and the origins of magnetospheric hot plasmas will be determined. Further, the Jovian magnetosphere and Io torus will be imaged during Jupiter flyby. The investigative approach is twofold. (1) Perform remote sensing of the magnetospheric energetic (E > 7 keV) ion plasmas by detecting and imaging charge-exchange neutrals, created when magnetospheric ions capture electrons from ambient neutral gas. Such escaping neutrals were detected by the Voyager l spacecraft outside Saturn’s magnetosphere and can be used like photons to form images of the emitting regions, as has been demonstrated at Earth. (2) Determine through in-situ measurements the 3-D particle distribution functions including ion composition and charge states (E > 3 keV/e). The combination of in-situ measurements with global images, together with analysis and interpretation techniques that include direct “forward modeling’’ and deconvolution by tomography, is expected to yield a global assessment of magnetospheric structure and dynamics, including (a) magnetospheric ring currents and hot plasma populations, (b) magnetic field distortions, (c) electric field configuration, (d) particle injection boundaries associated with magnetic storms and substorms, and (e) the connection of the magnetosphere to ionospheric altitudes. Titan and its torus will stand out in energetic neutral images throughout the Cassini orbit, and thus serve as a continuous remote probe of ion flux variations near 20R
S (e.g., magnetopause crossings and substorm plasma injections). The Titan exosphere and its cometary interaction with magnetospheric plasmas will be imaged in detail on each flyby. The three principal sensors of MIMI consists of an ion and neutral camera (INCA), a charge–energy–mass-spectrometer (CHEMS) essentially identical to our instrument flown on the ISTP/Geotail spacecraft, and the low energy magnetospheric measurements system (LEMMS), an advanced design of one of our sensors flown on the Galileo spacecraft. The INCA head is a large geometry factor (G ∼ 2.4 cm2 sr) foil time-of-flight (TOF) camera that separately registers the incident direction of either energetic neutral atoms (ENA) or ion species (≥5∘ full width half maximum) over the range 7 keV/nuc < E < 3 MeV/nuc. CHEMS uses electrostatic deflection, TOF, and energy measurement to determine ion energy, charge state, mass, and 3-D anisotropy in the range 3 ≤ E ≤ 220 keV/e with good (∼0.05 cm2 sr) sensitivity. LEMMS is a two-ended telescope that measures ions in the range 0.03 ≤ E ≤ 18 MeV and electrons 0.015 ≤ E≤ 0.884 MeV in the forward direction (G ∼ 0.02 cm2 sr), while high energy electrons (0.1–5 MeV) and ions (1.6–160 MeV) are measured from the back direction (G ∼ 0.4 cm2 sr). The latter are relevant to inner magnetosphere studies of diffusion processes and satellite microsignatures as well as cosmic ray albedo neutron decay (CRAND). Our analyses of Voyager energetic neutral particle and Lyman-α measurements show that INCA will provide statistically significant global magnetospheric images from a distance of ∼60 R
S every 2–3 h (every ∼10 min from ∼20 R
S). Moreover, during Titan flybys, INCA will provide images of the interaction of the Titan exosphere with the Saturn magnetosphere every 1.5 min. Time resolution for charged particle measurements can be < 0.1 s, which is more than adequate for microsignature studies. Data obtained during Venus-2 flyby and Earth swingby in June and August 1999, respectively, and Jupiter flyby in December 2000 to January 2001 show that the instrument is performing well, has made important and heretofore unobtainable measurements in interplanetary space at Jupiter, and will likely obtain high-quality data throughout each orbit of the Cassini mission at Saturn. Sample data from each of the three sensors during the August 18 Earth swingby are shown, including the first ENA image of part of the ring current obtained by an instrument specifically designed for this purpose. Similarily, measurements in cis-Jovian space include the first detailed charge state determination of Iogenic ions and several ENA images of that planet’s magnetosphere.This revised version was published online in July 2005 with a corrected cover date. 相似文献
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Jessica M. Sunshine Michael F. A’Hearn Olivier Groussin Lucy A. McFadden Kenneth P. Klaasen Peter H. Schultz Carey M. Lisse 《Space Science Reviews》2005,117(1-2):269-295
The science payload on the Deep Impact mission includes a 1.05–4.8 μm infrared spectrometer with a spectral resolution ranging
from R∼200–900. The Deep Impact IR spectrometer was designed to optimize, within engineering and cost constraints, observations
of the dust, gas, and nucleus of 9P/Tempel 1. The wavelength range includes absorption and emission features from ices, silicates,
organics, and many gases that are known to be, or anticipated to be, present on comets. The expected data will provide measurements
at previously unseen spatial resolution before, during, and after our cratering experiment at the comet 9P/Tempel 1. This
article explores the unique aspects of the Deep Impact IR spectrometer experiment, presents a range of expectations for spectral
data of 9P/Tempel 1, and summarizes the specific science objectives at each phase of the mission. 相似文献