智能便携式三表数据处理器

介绍一种智能型的便携式三表数据处理器,解决了三表检定数据处理繁琐的问题。     

基于TOPSIS算法的数据中继任务动态优先级设置方法

针对中继卫星系统资源分配中的数据中继任务优先级设置问题开展研究,提出动态优先级评价方法,打破现有基于预设固化时段完成冲突消解的任务规划模式.综合考虑用户、需求,以及任务重要性等因素,建立任务优先级两级评价指标体系.其中,刚性优先级用于度量资源申请的必要性,柔性优先级用于维护资源分配的公平性,同时促进资源使用的合理性.详细列举了各项指标的量化模型,给出了柔性指标综合计算算法.在实验分析中,通过大量数据统计,测试了所提方法的可行性和有效性.     

用户星天线指向控制设计初探

在数据中继卫星系统中，为保证用户星和中继星间的通信，用户星天线要精确指向中继星。由于天线指向系统和姿态控制系统间存在动态耦合，天线桅杆又有拉伸和扭转变形，所以仅靠卫星的姿态控制不能达到要求的指向精度，必须采用独立的指向控制系统。本文针对这一情况，首先分析了用户星天线指向跟踪信号，并设计单轴天线控制器。仿真结果表明，用典型跟踪信号作为输入，可得到满意的跟踪精度。     

基于CCSDS的遥科学试验台通信链路的概念研究

为了有效地利用空间站资源,提出了遥科学的概念。利用空间站的微重力环境所做的各种科学实验,需要空地间交互地进行通信,空间数据系统咨询委员会（ＣＣＳＤＳ）为这种通信键路制定了一系列标准。着重讨论了遥科学对通信链路的要求,适于遥科学实验的空间数据系统模型以及天基、地基通信系统框图。     

跨产品结构树的产品工装数据组织与关联设计方法

深入研究了CATIA/VPM并行协同设计环境下产品与工装之间的数据组织管理及相应的关联设计技术,提出了跨产品结构树的产品工装数据组织管理及关联设计方法。该技术既是对现有全三维关联设计技术的进一步探索,又为实现产品工装一体化设计提供了一条可行的解决途径,具有重要的应用价值和现实意义。     

OpenGL在增材制造数据处理系统中的应用研究

介绍了增材制造技术,分析了OpenGL的基本原理,论述了OpenGL在增材制造数据处理系统的图形显示与操作、几何交互操作功能等方面的实现方法,并在电子束熔丝成形数据处理系统中进行了应用验证.利用OpenGL图形库,使数据处理系统的准确性、实用性和交互性得到了提高.     

The impact of error covariance matrix structure of GRACE’s gravity solution on the mass flux estimates of Greenland ice sheet

The error variance-covariance matrices of the monthly GRACE gravity field models are usually well-structured (e.g., order-leading) to contain the error information of the monthly gravity field models, and they are important information to further improve the accuracy of the estimated mass transportation by a post-processing scheme. Intensive studies have been performed to understand the impact of different approximations of the full error variance-covariance matrix on the mass estimates obtained with the conventional GRACE-post processing methods (e.g., the de-striping method). In this study, based on the variants of the mascon approach which treat monthly GRACE solutions as input, we consider four different structures to the error variance-covariance matrix, (i) full matrix, (ii) block diagonal matrix, (iii) diagonal matrix, and (iv) identity matrix, and examine their impact on the mass transport estimates in Greenland. Using both synthetic and real data, we analyze the results at four temporal scales: (i) the long-term decadal scale, (ii) the inter-annual scale, (iii) the seasonal scale, and (iv) the monthly scale. Based on the synthetic study, we find that for the recovery of the long-term trend, the application of the diagonal structure obtains the best estimates. This is caused by the amplification of the model error in the mascon approach when considering the full and block diagonal structures of error variance-covariance matrix, not due to any imperfection of them. Therefore, we emphasize that one should be aware of mascon model deficiency in the mascon approach. Furthermore, the best inter-annual, seasonal and monthly mass estimates are derived by considering the block diagonal and full structures. This is caused by the behavior of the bias and the unique parameterization error in the case of different structures. A similar finding is also presented in the real data case. Finally, our analysis denotes the necessity of releasing the block diagonal structure together with the official monthly gravity field model for the GRACE Follow-On mission, instead of releasing only the diagonal structure as done for the GRACE mission.     

A new method for improving the performance of an ionospheric model developed by multi-instrument measurements based on artificial neural network

There are remarkable ionospheric discrepancies between space-borne (COSMIC) measurements and ground-based (ionosonde) observations, the discrepancies could decrease the accuracies of the ionospheric model developed by multi-source data seriously. To reduce the discrepancies between two observational systems, the peak frequency (foF2) and peak height (hmF2) derived from the COSMIC and ionosonde data are used to develop the ionospheric models by an artificial neural network (ANN) method, respectively. The averaged root-mean-square errors (RMSEs) of COSPF (COSMIC peak frequency model), COSPH (COSMIC peak height model), IONOPF (Ionosonde peak frequency model) and IONOPH (Ionosonde peak height model) are 0.58 MHz, 19.59 km, 0.92 MHz and 23.40 km, respectively. The results indicate that the discrepancies between these models are dependent on universal time, geographic latitude and seasons. The peak frequencies measured by COSMIC are generally larger than ionosonde’s observations in the nighttime or middle-latitudes with the amplitude of lower than 25%, while the averaged peak height derived from COSMIC is smaller than ionosonde’s data in the polar regions. The differences between ANN-based maps and references show that the discrepancies between two ionospheric detecting techniques are proportional to the intensity of solar radiation. Besides, a new method based on the ANN technique is proposed to reduce the discrepancies for improving ionospheric models developed by multiple measurements, the results indicate that the RMSEs of ANN models optimized by the method are 14–25% lower than the models without the application of the method. Furthermore, the ionospheric model built by the multiple measurements with the application of the method is more powerful in capturing the ionospheric dynamic physics features, such as equatorial ionization, Weddell Sea, mid-latitude summer nighttime and winter anomalies. In conclusion, the new method is significant in improving the accuracy and physical characteristics of an ionospheric model based on multi-source observations.     

Statistical analysis of geomagnetic field variations during solar eclipses

We investigate the geomagnetic field variations recorded by INTERMAGNET geomagnetic observatories, which are observed while the Moon’s umbra or penumbra passed over them during a solar eclipse event. Though it is generally considered that the geomagnetic field can be modulated during solar eclipses, the effect of the solar eclipse on the observed geomagnetic field has proved subtle to be detected. Instead of exploring the geomagnetic field as a case study, we analyze 207 geomagnetic manifestations acquired by 100 geomagnetic observatories during 39 solar eclipses occurring from 1991 to 2016. As a result of examining a pattern of the geomagnetic field variation on average, we confirm that the effect can be seen over an interval of 180?min centered at the time of maximum eclipse on a site of a geomagnetic observatory. That is, demonstrate an increase in the Y component of the geomagnetic field and decreases in the X component and the total strength of the geomagnetic field. We also find that the effect can be overwhelmed, depending more sensitively on the level of daily geomagnetic events than on the level of solar activity and/or the phase of solar cycle. We have demonstrated it by dividing the whole data set into subsets based on parameters of the geomagnetic field, solar activity, and solar eclipses. It is suggested, therefore, that an evidence of the solar eclipse effect can be revealed even at the solar maximum, as long as the day of the solar eclipse is magnetically quiet.     

航天器推力器测试台高速实时数据采集系统的设计与实现

为了满足航天器卫星推力器真空热试车工程背景的需要,在VC++环境下利用多线程技术设计航天器推力器试验台高速数据采集系统,本文详细的研究了设计中的关键性技术及解决方案,试验验证该方案是可行的,并有一定的通用性。