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41.
简要介绍了海洋一号卫星星载GPS接收机的定位原理、流程和应用,探讨了一种在轨定位结果的确认和互验方法.借助于卫星工具包软件(STK),利用NASA网站公布的HY-1卫星两行根数(TLE)进行卫星轨道推算,生成星下点位置,并与相应时刻星载GPS接收机实测数据得到的星下点位置进行比较,由此得到两种方法定位结果之间的偏差,用实际在轨数据验证了两者的位置符合程度. 相似文献
42.
田春蓉%周秋明%王建华%尚蕾%廖宏 《宇航材料工艺》2005,35(1):52-55
探讨了胶黏剂黏度、硬铝表面处理方式及硅烷偶联剂KH-560的使用方式等因素对硬铝板/ZN-1阻尼材料复合结构件的粘接性能的影响。研究表明:如果硬铝板表面采用砂纸打磨处理时,采用黏度较低的TC-1环氧树脂胶或者在黏度较高的J-22环氧树脂胶中添加2%的硅烷偶联剂KH-560可以获得优异的粘接效果;当硬铝板表面采用铬酸阳极化处理时,两种胶黏剂均能获得优异的粘接效果。 相似文献
43.
利用UCC1控制器作为核心,构建具有三维空间连续扫描功能的测量机控制系统的方法,并简要介绍了UCC1控制器的功能及控制系统硬件电路的设计。 相似文献
44.
阐述了ART1神经网络在制造单元设计过程中形成零件族的基本方法,并在基于MATLAB的软件平台上,利用其神经网络工具箱对生产过程中的实际情况进行了仿真和应用。 相似文献
45.
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
46.
Michael J. S. Belton Karen J. Meech Michael F. A’Hearn Olivier Groussin Lucy Mcfadden Carey Lisse Yanga R. Fernández Jana PittichovÁ Henry Hsieh Jochen Kissel Kenneth Klaasen Philippe Lamy Dina Prialnik Jessica Sunshine Peter Thomas Imre Toth 《Space Science Reviews》2005,117(1-2):137-160
In 1998, Comet 9P/Tempel 1 was chosen as the target of the Deep Impact mission (A’Hearn, M. F., Belton, M. J. S., and Delamere, A., Space Sci. Rev., 2005) even though very little was known about its physical properties. Efforts were immediately begun to improve this situation
by the Deep Impact Science Team leading to the founding of a worldwide observing campaign (Meech et al., Space Sci. Rev., 2005a). This campaign has already produced a great deal of information on the global properties of the comet’s nucleus
(summarized in Table I) that is vital to the planning and the assessment of the chances of success at the impact and encounter.
Since the mission was begun the successful encounters of the Deep Space 1 spacecraft at Comet 19P/Borrelly and the Stardust spacecraft at Comet 81P/Wild 2 have occurred yielding new information on the state of the nuclei of these two comets. This
information, together with earlier results on the nucleus of comet 1P/Halley from the European Space Agency’s Giotto, the Soviet Vega mission, and various ground-based observational and theoretical studies, is used as a basis for conjectures on the morphological,
geological, mechanical, and compositional properties of the surface and subsurface that Deep Impact may find at 9P/Tempel 1. We adopt the following working values (circa December 2004) for the nucleus parameters of prime importance to Deep Impact as follows: mean effective radius = 3.25± 0.2 km, shape – irregular triaxial ellipsoid with a/b = 3.2± 0.4 and overall dimensions of ∼14.4 × 4.4 × 4.4 km, principal axis rotation with period = 41.85± 0.1 hr, pole directions
(RA, Dec, J2000) = 46± 10, 73± 10 deg (Pole 1) or 287± 14, 16.5± 10 deg (Pole 2) (the two poles are photometrically, but not
geometrically, equivalent), Kron-Cousins (V-R) color = 0.56± 0.02, V-band geometric albedo = 0.04± 0.01, R-band geometric
albedo = 0.05± 0.01, R-band H(1,1,0) = 14.441± 0.067, and mass ∼7×1013 kg assuming a bulk density of 500 kg m−3. As these are working values, {i.e.}, based on preliminary analyses, it is expected that adjustments to their values may be made before encounter
as improved estimates become available through further analysis of the large database being made available by the Deep Impact observing campaign. Given the parameters listed above the impact will occur in an environment where the local gravity is
estimated at 0.027–0.04 cm s−2 and the escape velocity between 1.4 and 2 m s−1. For both of the rotation poles found here, the Deep Impact spacecraft on approach to encounter will find the rotation axis close to the plane of the sky (aspect angles 82.2 and 69.7
deg. for pole 1 and 2, respectively). However, until the rotation period estimate is substantially improved, it will remain
uncertain whether the impactor will collide with the broadside or the ends of the nucleus. 相似文献
47.
飞行任务对卫星轨道提出指标要求,这些指标决定了卫星轨道参数的容许偏差范围。结合太阳同步(准)回归轨道卫星的轨道特性,针对覆盖重叠率、太阳同步等指标,使用解析方法讨论了大气阻力摄动影响下轨道参数的容许偏差,通过分析可以初步确定轨道控制策略及能量需求,最终为轨道保持方法的设计提供参考和依据。 相似文献
48.
49.
编队飞行卫星群构型保持及初始化 总被引:3,自引:0,他引:3
导出了基于相对轨道要素的编队飞行卫星群轨道相对运动控制的轨道机动方程;提出了编队飞行卫星群轨道相对运动控制的轨道机动控制策略,利用不同方向的脉冲控制相对运动的轨道参数,包括轨道平面内机动和轨道平面外机动控制。根据相对轨道要素的变轨机动控制,进行编队飞行卫星群构型的初始化。这样的构型初始化可以视作一次特殊的变轨机动控制,很容易实现编队飞行构型的初始化机动。 相似文献
50.