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排序方式: 共有124条查询结果,搜索用时 173 毫秒
91.
92.
基于导航星域和K矢量的快速星图识别算法 总被引:1,自引:0,他引:1
星图识别算法是星敏感器的关键技术,快速性和可靠性一直是对其评价的重要指标。提出了基于K矢量查找表和导航星域联合进行超快速星图识别的方法。首先根据星敏感器视场和所能敏感的星等建立全天球导航星表;再依据K矢量的原则对全天的导航星按照星对角距进行分类,建立星对角距所对应导航星的K矢量和K矢量查找表。利用星敏感器视场中的4颗星构成6组星对角距,将其中的5组星对角距所对应K矢量查找表域的星对组进行导航星表域(简称导航星域)的变换,根据另外一组星对角距所对应的K矢量查找表域的值对前面5组导航星域的值同时进行索引比较,直接找到了满足条件的4颗导航星,即完成全天的星图识别。最后,通过计算机仿真,实验室模拟和真实星空实验三个层次验证了此方法的可靠性和快速性。 相似文献
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Tamara Bandikova Jakob Flury 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
The new release of the sensor and instrument data (Level-1B release 02) of the Gravity Recovery and Climate Experiment (GRACE) had a substantial impact on the improvement of the overall accuracy of the gravity field models. This has implied that improvements on the sensor data level can still significantly contribute to arriving closer to the GRACE baseline accuracy. The recent analysis of the GRACE star camera data (SCA1B RL02) revealed their unexpectedly higher noise. As the star camera (SCA) data are essential for the processing of the K-band ranging data and the accelerometer data, thorough investigation of the data set was needed. We fully reexamined the SCA data processing from Level-1A to Level-1B with focus on the combination method of the data delivered by the two SCA heads. In the first step, we produced and compared our own combined attitude solution by applying two different combination methods on the SCA Level-1A data. The first method introduces the information about the anisotropic accuracy of the star camera measurement in terms of a weighing matrix. This method was applied in the official processing as well. The alternative method merges only the well determined SCA boresight directions. This method was implemented on the GRACE SCA data for the first time. Both methods were expected to provide optimal solution characteristic by the full accuracy about all three axes, which was confirmed. In the second step, we analyzed the differences between the official SCA1B RL02 data generated by the Jet Propulsion Laboratory (JPL) and our solution. SCA1B RL02 contains systematically higher noise of about a factor 3–4. The data analysis revealed that the reason is the incorrect implementation of algorithms in the JPL processing routines. After correct implementation of the combination method, significant improvement within the whole spectrum was achieved. Based on these results, the official reprocessing of the SCA data is suggested, as the SCA attitude data are one of the key observations needed for the gravity field recovery. 相似文献
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研究了一种利用捷联惯导、星敏感器和北斗接收机进行长航时高精度组合导航的方法.对捷联惯导系统误差、星敏感器安装误差、北斗定位误差分别进行建模,将星敏感器输出的载体姿态角、北斗接收机输出的载体位置与捷联惯导输出的对应参数分别相减作为量测,推导获得组合导航量测方程.针对长航时环境下可能面临量测噪声统计特性的不确定问题,采用简化的Sage-Husa自适应滤波算法进行组合导航滤波设计.仿真结果表明,该组合导航方法的定位精度达到±11.86m,定姿精度达到±0.27′,并且对量测噪声统计特性的突变具有较强的鲁棒性. 相似文献
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E. Georgescu H.U. Auster T. Takada J. Gloag H. Eichelberger K.-H. Fornaçon P. Brown C.M. Carr T.L. Zhang 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008,41(10):1579-1584
On TC-1 (Tan Ce 1), the equatorial spacecraft of the Double Star mission, a strong spin-synchronized magnetic interference from the solar panels was observed. In-flight correction techniques for spinning spacecraft that are based on minimizing spin tones in the spin-aligned component and in the magnitude of the ambient magnetic field are therefore not possible in this case. However, due to the fortunate situation that the spacecraft carries two flux-gate magnetometers on the same boom (at 0.5 m distance from each other), the spacecraft field effects could be removed from the spin-averaged data to achieve 0.2 nT relative accuracy, by using a gradiometer technique. Methodology and results are presented. The obtained accuracy allows the use of the data in multi-spacecraft studies together with the Cluster satellites. 相似文献
99.
国际商业航天的蓬勃发展带动了国内商业航天的兴起。以实现商业卫星高效便捷管理为目的,调研了国内外商业航天与商业航天测控的发展现状,分析了国外商业航天以及商业航天测控发展对我国商业航天测控管理的有关启示,得出了测控管理多元化大势所趋、适度鼓励商业航天测控发展势在必行等结论。同时,对我国商业航天测控管理中加强航天立法、探索商业航天测控管理新模式、加强商业卫星管理服务等问题进行了初步探讨,建议从国家层面、行业规范层面制定航天法规,卫星任务中心应支持对外联网,并加强商业航天测控地面站的国际合作,从而提高商业卫星频率、轨位、空间目标编目、发射与回收等管理服务能力。 相似文献
100.
针对栅格算法易受邻域星点影响导致误匹配的问题,提出了一种结合角距特征的改进栅格星图识别算法。首先介绍了改进栅格算法的原理,其次设计了融合栅格识别模式和星角距识别模式的算法实现流程,最后开展了基于不同视角下的大视场仿真星图的算法试验验证和性能分析。结果表明,由于角距特征具有旋转不变性和不易受观测星邻域星点分布影响等特点,结合角距特征对失效观测星进行再匹配的改进栅格算法,在兼顾存储量需求小、运行速度快等优势的同时,识别率和鲁棒性也得到了提升,最高识别率可达98.88%,在位置噪声干扰以及缺失星干扰下,改进算法的识别率仍可保持在95%,说明算法鲁棒性强,具有较好的应用前景。 相似文献