数据收集系统下行频偏校准与点频值计算

风云二号（ＦＹ－２）卫星在轨运行期间本振源必定产生一定的频率偏移,这就影响了数据收集平台接收系统（ＤＣＰＲ）相应于各种平台的报文锁相环路的频率捕获范围,严重时将无法解调出各种平台收集的气象数据,整个系统也将无法正常工作。为解决上述问题,介绍了ＤＣＰＲ下行频偏校准及点频值计算的方法。通过ＦＹ－２卫星在轨测试表明,在随机干扰比较严重的情况下,ＤＣＰＲ对各种平台报文接收解调的成功率优于９８％,取得了令人满意的结果。     

应变测量仪自动校准系统设计CSCD

针对飞机静力、疲劳、铁鸟及风洞等强度试验中大量使用由LXI EX1629应变测量仪组成的大型应变测量系统通道数多校准项目多,采用手动校准工作量大、周期长、效率低、并容易出错等问题。利用标准仪器通信接口和被校设备的LXI标准网络化测控系统的嵌入式设备高可靠性及快速通讯方式,在VEE Pro软件开发平台上,设计开发出一套应变测量仪自动校准系统,实现了应变量测量仪和应变量放大器多路同步快速自动校准。系统包括设备管理、校准及打印输出三个主模块。试验结果表明:系统运行可靠、有效、精度高。该校准系统在飞机研发试验中发挥了重要作用,具有广泛的应用前景。     

关于CCSDS体制数据安全保护实施位置的探讨

主要阐述CCSDS（空间数据系统咨询委员会）标准的信息安全问题，重点是航天器安全，从分析空间数据面临的安全威胁出发，讨论了CCSDS不同安全实施位置的特点；并在此基础上，通过对CCSDS业务及数据结构的影响对比，总结出不同安全实施方法的优缺点，该结合对于采用CCSDS标准的空间数据系统如何解决信息安全问题，具有一定的参考价值。     

The structure of the solar corona as observed by the Solar Extreme ultraviolet Rocket Telescope and Spectrograph

Data from the Solar Extreme-ultraviolet Rocket Telescope and Spectrograph (SERTS) have been used to address a number of important scientific problems. The primary strength of the SERTS data is the fact that this spectral range is rich with emission lines. Over 270 lines are seen in the SERTS active Sun spectrum, from 57 different ions. For example, multiple (≥4) lines are observed for all ionization states of iron from Fe IX to Fe XVII. Temperatures and densities have been derived for a number of active and quiet Sun regions, the coronal magnetic field strength has been estimated for both a plage region and an active region.     

Monitoring of rice cropping intensity in the upper Mekong Delta,Vietnam using time-series MODIS data

Information on rice growing areas is important for policymakers to devise agricultural plans. This research explores the monitoring of rice cropping intensity in the upper Mekong Delta, Vietnam (from 2001 to 2007) using time-series MODIS NDVI 250-m data. Data processing includes three steps: (1) noise is filtered from the time-series NDVI data using empirical mode decomposition (EMD); (2) endmembers are extracted from the filtered time-series data and trained in a linear mixture model (LMM) for classification of rice cropping systems; and (3) classification results are verified by comparing them with the ground-truth and statistical data. The results indicate that EMD is a good filter for noise removal from the time-series data. The classification results confirm the validity of LMM, giving an overall accuracy of 90.1% and a Kappa coefficient of 0.7. The lowest producer and user accuracies were associated with single crop rain-fed rice class due to the mixed pixel problems. A strong yearly correlation at the district level was revealed in the MODIS-derived areas (R² ? 0.9). Investigation of interannual changes in rice cropping intensity from 2001 to 2007 showed a remarkable conversion from double to triple crop irrigated rice from 2001 to 2003, especially in the Thoai Son and Phu Tan districts. A big conversion from triple crop rice back to double crop rice cultivation was also observed in Phu Tan from 2005 to 2006. These changes were verified by visual interpretation of Landsat images and examination of NDVI profiles.     

大容量信息实时传输技术研究

在信道带宽受限的条件下,实现大容量信息的实时传输是面向空间应用的遥科学技术要解决的核心问题之一。提出了将双总线寻址与双Ｂｕｆｆｅｒ相结合的技术结构,从而实现了在规定的传输协议、规定的信息道链路带宽的约束条件下,视频图像的实时无缝传输与主动遥操作。通过一些关键性技术难点的突破,达到了在２Ｍｂｉｔ／ｓ码速率下按ＣＣＳＤＳ（空间数据系统协调委员会）的位流协议在地基上实时复现出高质量的视频图像序列。     

Data processing center of RadioAstron space VLBI project

In this paper, questions on development, implementation, and operation of RadioAstron project Data Processing Center (DPC) are reviewed. The main components of the dedicated DPC are the computer complex with 1 TFlops/s performance, storage with memory capacity of approximately 10 PB, the network infrastructure, and the corresponding communication channels. Performance enhancement methods and resolution of information storage, archiving, and process problems of space VLBI high-speed digital data flows are analyzed. It is shown that successful operation of DPC is mainly provided by optimal organization of computer system structure, storage, and networking transmission. Some of the important key features of RadioAstron project DPC and its comparative differences from the standard VLBI procedures are considered.     

空间通信协议分析与一体化网络安全问题探讨

目前国际互联网体系结构及其协议虽然取得了巨大成功，但是当面对诸如长延时、多丢失、网络分区或节点生存周期短等环境时运行却不尽人意，尤其在缺乏基础设施或有限电源功率严格约束的空间环境下运行性能大为降低。文章在定量分析的基础上，讨论了空间通信网络的特点，对CCSDS的SCPS协议进行了简要综合分析，并且提出空间网络与地面网络互连时解决安全问题的一种可能途径。     

基于UKF的FADS/INS融合大气数据估计

针对飞行器在高速飞行时受气流干扰、惯性数据易发散等问题,从传感器数据融合角度出发,提出了通过无迹卡尔曼滤波(UKF)融合嵌入式大气数据观测系统(FADS)和惯性导航系统(INS)估计飞行器实时大气数据的算法。算法使用高维度非线性方程对惯性系统和大气系统间的关系建模,结合FADS与INS的数据,计算飞行器速度和高度,进而估算出攻角、侧滑角等参数。实验结果显示,与INS直接解算、扩展卡尔曼滤波(EKF)融合等原有估计方法相比,文章所述的算法在估计精度和系统稳定性方面均有所提高。     

基于多传感器数据融合技术的力学量测量系统研究

多传感器的数据融合已经在系统智能检测领域得到越来越多的应用,本论文针对传统的数据融合算法未考虑传感器自身可靠性这一不足,分析了面向传感器可靠性的数据融合算法,并在多元力学参数检测系统中加以应用,给出了系统的总体框架,并对数据融合的具体应用进行了分析,这对于进一步提高力学参数的智能传感检测及数据融合的研究具有一定的借鉴意义。     

Space Weather applications with CDPP/AMDA

AMDA (Automated Multi-Dataset Analysis), a new data analysis service, recently opened at the French Plasma Physics Data Center (CDPP). AMDA is developed according to the Virtual Observatory paradigm: it is a web-based facility for on-line analyses of space physics. Data may come from its own local database as well as remote ones. This tool allows the user to perform classical manipulations such as data visualization, parameter computation and data extraction. AMDA also offers innovative functionalities such as event searches on the content of the data in either visual or automated ways, generation, use and management of time tables (event lists). The general functionalities of AMDA are presented in the context of Space Weather with example scientific use cases.     

GPS single-frequency orbit determination for low Earth orbiting satellites

The determination of high-precision orbits for Low Earth Orbiting (LEO) satellites (e.g., CHAMP, GRACE, MetOp-A) is based on dual-frequency tracking data from on-board GPS (Global Positioning System) receivers. The two frequencies allow it to eliminate the first order ionosphere effects. Data screening and precise orbit determination (POD) procedures are optimized under the assumption of the availability of two frequencies.     

Re-entry of orbital debris observed by Chung-Li VHF radar with MEDAC

MEDAC (Meteor Echo Detection and Collection) system, a product of University of Colorado, has become part of Chung-Li VHF facilities since July 12, 1989. MEDAC is installed to observe the mesospheric winds from Doppler echos returned by meteor trails in the upper atmosphere. However, the time variations in the in-phase and quadrature components of the signals can be used to derive the time history of the meteor trail formation. The meteor flight speed in the atmosphere is hence deduced. Preliminary analysis of some data taken from July 12 to July 17 of 1989 indicates that there are some “meteor” trails that could have been produced by the reentry of orbital debris into the atmosphere. The criteria of the flight speed and the ionization height are used for selecting an orbital debris trail from pools of “meteor” trails. The relative flux intensities between the reentry orbital debris flux as tentatively identified in this paper and the meteor flux is about 1 to 100.     

基于北斗定位的多义路径识别解决方案

针对高速公路路网络存在的多义路径问题,提出一种基于北斗定位技术的高速公路通行卡设计方案。将北斗芯片与高速公路ETC通行卡集成,在车辆行驶过程中精确记录其位置信息,并将其与地图数据进行匹配,得到车辆的实际行驶轨迹,并以此为依据收取通行费用,有效避免多义路径现象,有助于实现高速公路大范围联网收费。与目前已有的RFID标识站方案及车牌自动识别方案相比,本方案具有识别结果精确、对现有系统改动较小、受外界影响较小等特点,具有广泛的应用价值。     

Proposed reference models for nitrous oxide and methane in the middle atmosphere

Data from the Stratospheric and Mesospheric Sounder (SAMS) on the Nimbus 7 satellite, for the three years from January 1979–December 1981, are used to prepare a reference model for the long-lived trace gases methane (CH₄) and nitrous oxide (N₂O) in the stratosphere. The model is presented in tabular form on seventeen pressure surfaces from 20 to 0.1 mb, in 10° latitude bins from 50S to 70N, and for each month of the year. The means by which the data quality and interannual variability, and some of the more interesting globally and seasonally variable features of the data are discussed briefly.     

YODA++: A proposal for a semi-automatic space mission control

YODA++ is a proposal for a semi-automated data handling and analysis system for the PAMELA space experiment. The core of the routines have been developed to process a stream of raw data downlinked from the Resurs DK1 satellite (housing PAMELA) to the ground station in Moscow. Raw data consist of scientific data and are complemented by housekeeping information. Housekeeping information will be analyzed within a short time from download (1 h) in order to monitor the status of the experiment and to foreseen the mission acquisition planning. A prototype for the data visualization will run on an APACHE TOMCAT web application server, providing an off-line analysis tool using a browser and part of code for the system maintenance. Data retrieving development is in production phase, while a GUI interface for human friendly monitoring is on preliminary phase as well as a JavaServerPages/JavaServerFaces (JSP/JSF) web application facility. On a longer timescale (1–3 h from download) scientific data are analyzed. The data storage core will be a mix of CERNs ROOT files structure and MySQL as a relational database. YODA++ is currently being used in the integration and testing on ground of PAMELA data.     

Italian polar data center for capacity building associated with the IHY

The International Heliophysical Year offers a good opportunity to develop and coordinate studies on the Sun–Earth system by using a large variety of simultaneous data obtained by satellite/spacecraft and ground based instruments. Among these data we recall the ones coming from solar and interplanetary medium observations, auroral, neutron monitor, geomagnetic field, ionospheric, meteorological, and other atmospheric observatories. In this context, an Information System for the Italian Research in Antarctica has started in 2003, aiming to collect information on the scientific research projects funded by the National Antarctic Research Program of Italy since its establishment (1985). It belongs to Joint Committee on Antarctic Data Management of Scientific Committee on Antarctic Research as Italian Antarctic Data Center. This project, as the Italian Polar Database, gathers also information on research activities conducted in North Pole regions. This Information System can be a relevant resource for capacity building associated with the International Heliophysical Year, especially for people involved in interdisciplinary researches. We describe the present status of the Italian Polar Data Center and its potential use.     

基于MHD模拟数据的正午午夜子午面磁层顶位形研究

通过分析太阳风-磁层-电离层系统的三维全球磁流体力学(MHD)模型的计算数据, 给出了正午-午夜子午面磁层顶位形的定量模型. 分析表明, 正午-午夜子午面磁层顶位形可以用文献[3]提出的基于卫星观测数据的、描述赤道面磁层顶位形的函数来描述. 与赤道面磁层顶不同, 正午-午夜子午面磁层顶位形更为复杂. 在忽略极尖区(cusp)的简化条件下, 磁层顶位形仍需利用两条曲线来拟合. 太阳风动压Dp与行星际磁场分量Bz是控制磁层顶位形的主要因素. 行星际磁场为北向时, 磁场增强, 日下点距离r0增大; 行星际磁场为南向时, 磁场增强, 磁层顶日下点距离r0减小. 整体而言, 行星际磁场分量Bz由南转北时, r0增大, 且Bz对r0的影响减弱. 太阳风动压Dp是控制磁层顶日下点的主要因素, Dp增大, r0减小. 磁层顶位形的另一个参数磁层顶磁尾张角α, 随着行星际磁场南向分量增强而增大, 即磁层顶张开程度更加显著, 更多的磁通量由向阳侧传输到夜侧; Dp增大, α略增大, 这意味着Dp对磁通量由日侧向夜侧的传输也有一定的贡献.      

International scientific optical network for space debris research

A joint team of researchers under the auspices of the Center for Space Debris Information Collection, Processing and Analysis of the Russian Academy of Sciences collaborates with 15 observatories around the world to perform observations of space debris. For this purpose, 14 telescopes were equipped with charge-coupled device (CCD) cameras, Global Positioning System (GPS) receivers, CCD frame processing and ephemeris computation software, with the support of the European and Russian grants. Many of the observation campaigns were carried out in collaboration with the Astronomical Institute of the University of Bern (AIUB) team operating at the Zimmerwald observatory and conducting research for the European Space Agency (ESA), using the Tenerife/Teide telescope for searching and tracking of unknown objects in the geostationary region (GEO). More than 130,000 measurements of space objects along a GEO arc of 340.9°, collected and processed at Space Debris Data Base in the Ballistic Center of the Keldysh Institute of Applied Mathematics (KIAM) in 2005–2006, allowed us to find 288 GEO objects that are absent in the public orbital databases and to determine their orbital elements. Methods of discovering and tracking small space debris fragments at high orbits were developed and tested. About 40 of 150 detected unknown objects of magnitudes 15–20.5 were tracked during many months. A series of dedicated 22-cm telescopes with large field of view for GEO survey tasks is in process of construction. 7 60-cm telescopes will be modernized in 2007.