排序方式： 共有12条查询结果，搜索用时 15 毫秒
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深渊着陆器在下潜过程中,由于受到海流的影响,其坐底位置会偏离投放点,偏离量和偏离方向很难估计,而声学水下定位方法在深渊海区不太适用.通过在海面进行气枪十字放炮作业,利用炮点准确位置和时间信息,以及海底地震仪(Ocean Bottom Seismometer,OBS)记录的直达水波到时,对深渊着陆器的坐底位置进行精确测量可以提供有效定位数据.该方法对采集得到的数据进行预处理,使用蒙托卡洛方法结合最小二乘法,对万泉号着陆器实际坐底位置进行了反演校正,得到三个潜次的位置校正偏移量分别为211m、178m、861m,偏移方向各不相同,校正精度为±20m,比以往的定位精度大为提高.此外,该方法测量确定了三个海底标志物的精确位置,为未来万米无人或载人潜器提供了可靠的水下参考坐标. 相似文献
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TJ-1模拟月壤承载特性的现场试验研究 总被引：1，自引：0，他引：1
采用TJ-1模拟月壤作为试验材料,通过静力触探、静载荷试验的对比分析,探讨适合月壤承载力计算的经验公式,以期为未来载人登月时宇航员和着陆器登陆可能涉及到有关月面承载能力的问题提供必要的参考。首先,使用近255 t TJ-1模拟月壤人工制备出13 m×12 m×1.2 m试验用地基,后在试验地基均匀布置6个静力触探测点和2个静载荷试验测点进行测试。针对太沙基承载力计算半经验公式以及规范和国内外学者提出的12个适合中密实砂土静力触探承载力计算的经验公式,对试验结果进行探讨。发现直接运用太沙基提出的半经验公式计算月壤承载力结果明显偏小,而由联合试验小组提出的经验公式 能够用来近似计算月壤地基承载力。计算结果表明,该经验公式在计算承载力时能够与静载荷试验值较好的吻合。 相似文献
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The Mars climate database (MCD) is a database of statistics based on output from physically consistent numerical model simulations which describe the climate and surface environment of Mars. It is used here to predict the meteorological environment of the Beagle 2 lander site. The database was constructed directly on the basis of output from multiannual integrations of two general circulation models, developed jointly at Laboratoire de Météorologie Dynamique du Centre National de la Recherche Scientifique, France, and the University of Oxford, UK. In an atmosphere with dust opacities similar to that observed by Mars Global Surveyor, the predicted surface temperature at the time of landing (Ls=322°, 13:00 local time), is , and varying between ∼186 and over the Martian day. The predicted air temperature at above the surface, the height of the fully extended Beagle 2 robot arm, is at the time of landing. The expected mean wind near the surface on landing is north-westerly in direction, becoming more southerly over the mission. An increase in mean surface pressure is expected during the mission. Heavy global dust storm predictions are discussed; conditions which may only occur in the extreme as the expected time of landing is around the end of the main dust storm period. Past observations show approximately a one in five chance of a large-scale dust storm in a whole Mars year over the landing region, Isidis Planitia. This statistic results from observations of global, encircling, regional and local dust storms but does not include any small-scale dust “events” such as dust devils. 相似文献
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着陆器足垫垂直冲击模型试验研究 总被引：1，自引：0，他引：1
着陆器着陆过程中会产生巨大的冲击作用,影响其内部精密仪器的正常工作。因此,研究着陆器足垫与土体相互作用对着陆器软着陆具有重要意义。基于对着陆过程的研究,将问题分解为垂直冲击和水平滑动两个方向的运动,并通过力的平衡和动量定理建立了垂直冲击的动力模型。利用独立研发的垂直冲击模型试验装置,探讨了冲击过程中土体密实度、冲击速率和冲击质量等对足垫刺入深度、最大轴力和最大加速度等的影响。分析结果表明,足垫刺入深度和最大轴力都随着冲击能量的增大而增大,并且逐渐趋于平稳。土体越密实、冲击质量越小,足垫加速度峰值则越大。试验结果还与动力模型进行了对比,结果表明,动力模型能合理地反映出着陆器在垂直冲击阶段的动力特性。 相似文献
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Unmanned mobile robots for surface exploration of the Moon or planets have been extensively studied and developed. A lunar
rover is expected to travel safely in a wide area and explore in detail. Japanese lunar robotics exploration is under study
to conduct an unmanned geological survey in the vicinity of central peaks of impact craters for investigation of the sub-surface
materials. This will give us the key information to study the lunar inner structure and understand the Moon’s origin and evolution
as well as to investigate the evolution of magma ocean and later igneous processes. To carry out the geological exploration
in the central peak, lander and rover co-operative exploration is proposed. The working group has been conducting feasibility
study of advance technologies. This paper addresses an overview of lunar exploration with lander and rover and also enumerates
future technologies to be established.
The rover R&D group has developed an innovative science micro rover with a new mobility system and a lightweight manipulator.
The design and implementation of a science rover for the near future lunar missions requiring long traverses and scientific
observations are described and some experimental results are presented. 相似文献
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火星研究的近期进展(英文) 总被引：1，自引：0，他引：1
Jiang Shaoyong 《地学前缘》1998,5(1):49-45
火星研究的历史可分为望远镜探测阶段和宇宙飞船探测阶段。本文简短回顾了Ｍａｒｉｎｅｒ４宇宙飞船（１９６５）,Ｍａｒｉｎｅｒ６和７（１９６９）,Ｍａｒｉｎｅｒ９（１９７１）和Ｖｉｋｉｎｇ１和２（１９７６）等的探测成果。火星探路者飞船是海盗２号以后的第一个火星着陆器,它于１９９６年下半年发射升空,于１９９７年７月１４日在火星表面着陆。通过火星探路者飞船对火星所做的分析,可以得出的结论是：（１）在火星的历史中已存在着水,因此,火星在过去曾是富水的、温暖的和潮湿的;（２）火星表面有许多火山口及火山,但没有大陆;（３）在火星上既有镁铁质岩石,也有硅质岩石;（４）火星的气候曾一度是温和的,有厚厚的大气圈及流水,这在过去有可能是一种能维持生命的环境。 相似文献
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一种改进的降落影像序列特征匹配方法 总被引：1，自引：1，他引：0
针对传统SIFT匹配方法用于嫦娥三号降落影像匹配效率低的问题,提出了一种改进的降落影像序列特征匹配方法。重构了着陆器垂直降落阶段拍摄过程的几何模型,并得到了不同降落影像中的同名匹配点之间的几何约束关系,然后通过SIFT方法进行影像中极值点的提取和特征描述,最终将几何模型约束用于极值点的匹配点搜索过程中,优化了匹配过程。采用嫦娥三号着陆器真实降落影像进行了试验,结果表明,改进方法能够取得较为稳定的匹配结果,且平均可以减少约为18%的匹配耗时,研究结果对后续深空探测任务的开展具有重要的参考价值。 相似文献
10.
In situ 《Estuarine, Coastal and Shelf Science》1999,49(6):813
Laboratory and in situ experiments were performed to assess the use of bromide as a tracer forin situ studies of benthic solute exchange. Bromide was used in the benthic chamber lander ‘ Elinor ’ for flux measurements in coastal sediments of the German Bight, Kiel Bight and Skagerrak (28–700 m water depth). Tracer and total oxygen uptake were monitored simultaneously in the same chamber incubation. Concurrently, in situ oxygen micro-profiles were recorded at the same locations by the profiling lander ‘ Profilur ’. Deployment in an anoxic silt (Kiel Bight) confirmed that in the absence of bioturbation and advection, tracer transport into the sediment was driven solely by molecular diffusion. This flux could be well described by a simple box model accounting for molecular diffusion only. In oxic sediments (German Bight and Skagerrak) enhanced exchange of bromide tracer due to bioirrigation parallelled enhanced oxygen uptake equivalent to a 4-fold molecular diffusive flux. Our experiments showed that incubations can be short. Depending on irrigation activity of the fauna, however, incubation length should exceed 3 h in order to provide a useful data base for flux calculations. The method demonstrating caveats is discussed and indicate possible improvements. The results show how the bromide tracer addition can be used as a tool for determining solute fluxes exceeding diffusive flux in benthic chamber incubations. 相似文献