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分析了国家天文台云南天文台射电频谱仪在230～300MHz、625～1500MHz、1000～2000MHz和2600～3800MHz记录到的11对具有双向漂移结构的Ⅲ型爆发.对双向Ⅲ型爆发的半功率持续时间、频率漂移率、偏振度等观测特征与普通Ⅲ型爆发作了比较,与Hα耀斑的关系也作了详细分析.得到这些事件的显著特征,并对双向Ⅲ型爆发作了定性解释. 相似文献
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首先回顾了火星重力场探测的历史、各有关探测器的轨道特征和获取的资料情况,特别对最成功的MGS项目的情况作了详细介绍。然后对确定火星重力场模型过程中的有关问题作了介绍,包括动力学模型、三体摄动问题、太阳光压和大气阻力模型等。重点介绍了其中的先验条件和求解重力场的算法,后者主要介绍GSFC采用的最小二乘法和先验约束方法及其数据定权和误差校准的经验。文中还对火星重力场与地形学进行了比较分析,并对火星重力场时变性的探测与研究作了重点讨论。最后对火星重力场探测中存在的主要问题作了详细讨论,并展望了我国第一颗火星探测器"萤火一号"对火星重力场研究的可能贡献。 相似文献
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对北京天文台动态频谱仪1996－1999年观测到的68群Ⅲ型爆发作了统计分析，并对这些事件的频率漂移、持续时间、偏振和带宽的基本特性作了定性分析。 相似文献
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1991年6月6日我们在太阳6659号活动区观测到了一个白光耀斑.这个白光耀斑伴有强烈的H_α、X射线和射电微波发射.我们对这次自光事件作了初步的分析研究,并对它的总能量作了粗略估计. 相似文献
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本文对晚型恒星的色球、过渡区和冕区的类太阳活动,恒星的耀发活动,及其与恒星的光谱型、自转、Rossby数、年龄等恒星基本参数的关系作了综合叙述,并对有关的物理问题和研究进展作了介绍。 相似文献
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本文对若干年的单频太阳微波辐射资料和D电离层骚扰资料作了分析,探讨了利用单频太阳观测资料对D电离层骚扰作提前半个月、提前五天予报及临时警报的可能性。 相似文献
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将方差分量估计（VCE）方法应用于ERS－2卫星的精密定轨,用SLR和PRARE资料计算了1998年前3个月的23个长度为5天的弧段（除了调整轨道的时段外,相邻弧段有两天的重叠）,从观测值残差分析和重叠弧段比较两个方面,考察VCE方法对定轨计算的影响,并给出了各组观测值的平均验后均方差,对观测值残差的分析表明,使用VCE方法明显地改善了观测值的拟合程度,但从阿卑（Abbey)标准对观测值残差的检验结果来看,使用VCE方法不能消除轨道中由力学模型和几何模型误差引入的系统差,重叠弧段比较的结果表明：（1）使用VCE方法缩小了重叠弧段的平均距离差,并改善了一部分权段明显不合理的偏离,使最后得到的轨道具有更均匀的精度,（2）相比较而言,VCE方法使相邻弧段靠拢的趋势在轨道切向体现得较为明显,由各组观测值的平均验后方差可见,说单个标准点观测值而言,部分SLR台站的观测资料在定轨计算中占有比其他观测资料更重的地位,纵观全文,使用VCE后得到的观测值的平衡验后均方差来确定资料的双重将比使用均方差更为合理。 相似文献
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《天文和天体物理学研究(英文版)》2016,(2)
An optical survey is the main technique for detecting space debris. Due to the specific characteristics of observation, the pointing errors and tracking errors of the telescope as well as image degradation may be significant, which make it difficult for astrometric calibration. Here we present an improved method that corrects the pointing and tracking errors, and measures the image position precisely. The pipeline is tested on a number of CCD images obtained from a 1-m telescope administered by Xinjiang Astronomical Observatory while observing a GPS satellite. The results show that the position measurement error of the background stars is around 0.1 pixel, while the time cost for a single frame is about 7.5 s; hence the reliability and accuracy of our method are demonstrated. In addition, our method shows a versatile and feasible way to perform space debris observation utilizing non-dedicated telescopes, which means more sensors could be involved and the ability to perform surveys could be improved. 相似文献
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It is difficult to use the single-station satellite laser ranging (SLR) data for orbit determination, due to the singular geometrical distribution of the observations. The single-station data produced by performing the diffuse- reflection SLR on the earth-orbiting space debris are therefore ineffective for orbit improvement. To solve this problem, we propose an orbit determination method by using single-station SLR data in aid of the two-line element set (TLE). For verifying its feasibility, this method is implemented and applied to the orbit determination of the satellite Ajisai, using the single-station SLR data of five passes in one day and the corresponding TLE. And on this basis, the five-day orbit prediction is generated, the result indicates that the errors of predicted positions are less than 40 m. In addition, the potential application of this method in the orbit improvement of space debris is discussed. 相似文献
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漂移扫描CCD用于地球同步轨道卫星观测的初步结果 总被引：1，自引：0，他引：1
对于地球同步轨道卫星,目前国内主要采用两种观测手段,即小光电望远镜短曝光观测和天文望远镜跟踪恒星(或卫星)观测.事实上,这两种手段都各自存在不足,尤其对于暗弱目标问题更加显著.利用CCD漂移扫描模式和凝视模式相结合观测地球同步轨道卫星具有明显的优势,小口径望远镜(口径约25cm)就能够获得高质量的目标和恒星圆星像与高精度的定位结果.本文重点阐述了获得高精度地球同步轨道卫星光学位置与星等的原理、方法及步骤;最后,利用实测资料的数据处理结果,分析了所获得的地球同步轨道卫星的内部精度及其误差源. 相似文献
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Zhang Fei-peng Huang Cheng Feng Chu-gang Dong Xiao-jun Liao Xin-hao 《Chinese Astronomy and Astrophysics》2001,25(4):641-489
Variance component estimation (VCE) is applied to precise orbit determination (POD) of the ERS-2 satellite. Twenty 5-day long arcs in the early three months in 1998 were calculated using the SLR and PRARE data. In the data the adjacent arcs overlap for two days except the intervals for orbit maneuver. The effect of VCE orbit determination on the calculation is investigated by an analysis of residuals and comparison of overlapping arcs, and the mean a posteriori standard deviation of each group of measured residuals is given. It is shown by the residuals analysis that the fitting of the measurements is significantly improved by VCD. However, according to Abbey criterion, VCD is not able to eliminate the systematic errors due to errors in the dynamic and geometric models. The results of the comparison of the overlapping arcs show that (1) VCE reduces the mean range deviation of overlapping arcs, especially where there are obviously unreasonable deviations, so that the orbit obtained has a more uniform precision; (2) By using VCE, adjacent arcs tend to close up and this is more apparent in the transverse direction. From the mean a posteriori standard error of each group of measurements, it can be seen that as far as the single normal point measurement is concerned, the data of some SLR stations are more important than other measurements in POD calculation. Generally speaking, determination of weighting by using VCE is more reasonable than by using initial standard deviation. 相似文献