大椭圆轨道上空间探测卫星轨道性能分析

本文以实践四号为例概述了卫星设计和运行的一般情况,着重论述卫星轨道设计的特点,并给出了表征轨道计算、发射窗口、卫星受晒、可测控条件等数据和图形.指出在历时2个月的运行中由遥测数据证明了轨道设计及初始姿态选择的正确性.      

软件定义卫星技术概念及发展

针对在轨卫星呈现海量化、网络化、智能化发展的趋势，重点探讨了软件定义卫星技术的产生背景、概念、内容与挑战。通过历史回顾，归纳卫星系统研制的3个阶段，指出目前卫星系统正在从平台、载荷优先向算法优先演进，这一趋势推动了软件定义卫星技术的产生与发展；阐述软件定义卫星技术的概念与边界，指出研究软件定义卫星技术的目的不是研制一类新型卫星，而是利用软件定义技术实现硬件资源虚拟化、系统软件平台化、应用软件多样化，提升卫星系统的网络化与智能化；分析软件定义卫星技术的主要内容与挑战，并对未来的发展进行展望。     

中国卫星的发展及应用

总结了我国卫星的发展道路。指出20年来我国卫星的发展主攻方向是应用卫星,主要目标是高中低三类轨道的通信、遥感和科学实验卫星,发展的步骤采取了步数少、步距大、起点高的途径,发展方针是依靠自力更生和全国大协作。文章扼要介绍了自80年代我国卫星转入应用后的情况,已在教育、广播、通信、资源、测绘、气象、科学研究和国防建设等领域应用并作出了巨大贡献。文章最后指出了我国90年代卫星应用的光明前景。     

中巴地球资源卫星的文件体系及特点

介绍了资源卫星的文件体系,指出了它的特点。文章介绍了３份系统级管理文件;４份系统级技术文件;两个树状文件一工作说明树和规范树;１１份接口数据单及其它一些文件。说明了它们的用途及主要内容。这些文件可供国际合作研制卫星参考,也可供中国卫星研制汲取其长处,加强研制管理,提高研制水平和效率。     

地球静止卫星粒子辐射屏蔽和充电设计原则

文章描述了总剂量屏蔽和减小静电充电影响的方法。并且指出总剂量方法足以满足卫星的在轨性能,改进充电设计用以满足卫星性能的要求。     

卫星用半导体器件失效模式和机理分布

以中国空间技术研究院电子元器件可靠性中心1987～1990四个年度数百份失效分析报告为依据,得到卫星用半导体器件解剖前失效模式分布:逻辑失控占36.3%,开路占22.2%等;失效机理分布:铝腐蚀占1 6.3%,使用不当占14.6%等。该项研究以第一手数据首次全面、系统指出卫星用器件失效模式和机理。为卫星可靠性设计、优选器件厂及器件厂采取措施提供重要依据。     

空间扫描

2007年度卫星产业收益跃升美国卫星产业协会于2008年6月11日公布了《2007年度全球卫星产业状况》报告。报告指出,2007年全球来自商业卫星产业的收益比2006年增长了16%,全球收入达1230亿美元,这意味着在2002-2007年,平均年度增长率为11·5%。包括卫星电视在内的卫星服务业收入持     

带有挠性附件卫星的自适应内模控制

导出了带有“拍打”运动的挠性卫星数学模型 ,并指出模型的不确定性 ;给出了卫星姿态控制器的基本形式 ,并分析了控制器参数的选取准则以保证姿态控制系统的稳定性 ;进而利用在轨辨识在线修正控制器参数形成了卫星姿态的自适应内模控制器。分析和仿真结果表明 ,所提出的自适应内模控制器能够有效提高大型卫星的姿态指向精度和稳定度     

“北斗”应用 落地生根 遍地开花

<正>2016年6月,中国政府发布《中国北斗卫星导航系统》白皮书,指出中国政府高度重视北斗系统应用及产业化,将北斗产业列为战略性新兴产业予以重点推进。目前,我国已形成包括基础产品、应用终端、运行服务等较为完整的北斗产业体系。目前,我国国内卫星导航总产值已达1900亿元,其中北斗系统贡献率约30%;国产北斗芯片、模块、天线等关键技术已取得全面突破,掌握卫星导航芯     

法国筹建欧洲军事侦察卫星系统

法国航空航天公司最近透露,法国正在与意大利、西班牙谈判制造第2颗欧洲军事侦察卫星埃利奥-2号卫星,以加速建立独立的欧洲军事侦察卫星系统。法国航空航天公司人士指出,建立独立的欧洲军事侦察卫星系统的设想是在海湾战争之后提出来的。在这场战争中,人们认识到卫星军事情报的重要性和“拥有起码的卫星侦察手段与摆脱对美国人的依赖”的必要性。     

Regional gravity field model in Pakistan area from the combination of CHAMP,GRACE and ground data using least squares collocation: A case study

This study describes a methodology of recovery of the Earth’s gravity field from CHAMP and GRACE satellites data in Pakistan using least squares collocation (LSC) based downward continuation technique. The CHAMP height anomalies and GRACE gravity disturbances derived from the observed satellite data have been used in combination solution using LSC with observed gravity values at the Earth surface. The combined covariance functions of height anomalies and/or gravity disturbances at satellite altitudes and observed gravity anomalies at Earth surface have been used as the basis for combination and downward continuation solution. The variance of predicted gravity anomalies from GRACE gravity disturbances is relatively lower than the corresponding results of gravity anomalies from CHAMP height anomalies. This fact may be attributed partly to the amplification of noise and partly to the unstable inverse transformation process of height anomalies to gravity anomalies. The impact of data error variance has been studied in the context of smoothing and noise reduction in the final solution of downward continuation using least squares collocation. The raising of data error suppresses the noise and as a result a smooth final solution is obtained. The prediction results appear to be dependent on the quality of data and goodness of combined covariance function, which are fairly comparable for the CHAMP and GRACE data. The recovered gravity field from satellite data appears to contribute mainly to medium and long wavelength parts of total gravity field spectrum. Due to flexibility of data handling in least squares collocation, this procedure is applicable to any observable of gravity field being at different altitudes and with different data spacing.     

Discriminating satellite IR anomalies associated with the MS 7.1 Yushu earthquake in China

In the process of exploring pre-earthquake thermal anomalies using satellite infrared data, Blackett et al. (2011) found that the previously reported anomalies before the 2001 Mw 7.7 Gujarat earthquake, in India, were related to positive biases caused by data gaps due to cloud cover and mosaicing of neighboring orbits of MODIS satellite data. They supposed that such effects could also be responsible for other cases. We noted a strip-shaped TIR anomaly on March 17th, 2010, 28?days before the Ms. 7.1 Yushu earthquake (Qin et al., 2011). Here we again investigate multi-year infrared satellite data in different bands to discriminate whether the anomaly is associated with the earthquake, or is only bias caused by the data gaps. From the water vapor images, we find lots of clouds that have TIR anomalies. However, on the cloudiness background, there is an obvious strip-shaped gap matching the tectonic faults almost perfectly. In particular, the animation loops of hourly water vapor images show that the cloud kept moving from west to east, while they never covered the strip-shaped gap. We consider that the cloud with this special spatial pattern should have implied the abnormal signals associated with the seismogenic process. Based on current physical models, the satellite IR anomalies both on TIR and water vapor bands can qualitatively be explained using synthetic mechanisms.     

Different space weather effects in anomalies of the high and low orbital satellites

Preliminary results of the EU INTAS Project 00810, which aims to improve the methods of safeguarding satellites in the Earth’s magnetosphere from the negative effects of the space environment, are presented. Anomaly data from the “Kosmos” series satellites in the period 1971–1999 are combined in one database, together with similar information on other spacecraft. This database contains, beyond the anomaly information, various characteristics of the space weather: geomagnetic activity indices (Ap, AE and Dst), fluxes and fluences of electrons and protons at different energies, high energy cosmic ray variations and other solar, interplanetary and solar wind data. A comparative analysis of the distribution of each of these parameters relative to satellite anomalies was carried out for the total number of anomalies (about 6000 events), and separately for high (5000 events) and low (about 800 events) altitude orbit satellites. No relation was found between low and high altitude satellite anomalies. Daily numbers of satellite anomalies, averaged by a superposed epoch method around sudden storm commencements and proton event onsets for high (>1500 km) and low (<1500 km) altitude orbits revealed a big difference in a behavior. Satellites were divided on several groups according to the orbital characteristics (altitude and inclination). The relation of satellite anomalies to the environmental parameters was found to be different for various orbits that should be taken into account under developing of the anomaly frequency models.     

Monitoring atomic clocks on board GNSS satellites

A method for monitoring atomic clocks on board Global Navigation Satellites System (GNSS) satellites is described to address the issue of clock related signal integrity in safety–critical applications of GNSS. The carrier-phase time transfer is employed in the clock monitoring method which enables tight tracking of the satellite onboard clocks and thus improves detectability of clock anomalies. Detecting onboard clock anomalies requires the ability to monitor clocks in real time, and a Kalman filter can then be utilized to estimate the phase offsets between the satellite clocks and ground clocks. This study, using the difference between the measured and predicted phase offset as a test statistic, sets a threshold for clock anomalies based on the prediction interval approach. Finally the validity of the monitoring method is examined by processing a set of real GNSS data that includes two recent incidents of clock anomalies in GNSS satellites.     

Detection of surface temperature anomaly of the Sea of Marmara

Monitoring sea surface temperature (SST) over a long-term and detecting the anomalies highly contribute to understanding the prevailing water quality of the sea. Earth observation satellite images are the key data sources that offer the long-term SST detection in a cost and time effective way. Since the Sea of Marmara in Türkiye is surrounded by the highly populated provinces, the water quality of the sea has gained importance for scientific and public communities over the years. This article emphasizes on the significance of detecting SST trend and corresponding anomalies of the Sea of Marmara over the past 32 years. To address the SST variations of the Sea of Marmara in time, a comprehensive set of both field and satellite data regarding SSTs were obtained within the context of this study. The SST trend and its anomalies between the years 1990 and 2021 were detected by applying Seasonal-Trend decomposition procedure based on LOESS (STL) method to NOAA OISST V2 data. On the other hand, spatial SST distribution was detected with Landsat-8, Sentinel-3 and NOAA OISST V2 satellite data. SST results were verified with the in-situ data within the scope of accuracy assessment. The results showed that SST time-series data performed an increasing trend and had anomalies mostly during the spring months in the recent years.     

基于LightGBM的卫星飞轮温度预测

为保障卫星的正常在轨运行，地面系统需要对卫星运行状态进行监控预警，其中对卫星各系统的温度监控尤为重要.温度不仅直接反映卫星系统的健康状态，更会对系统器件的性能和寿命造成影响.飞轮作为卫星姿态控制系统的重要组件，其温度变化是识别姿态控制系统状态的重要信息.卫星飞轮温度的预测与预警对卫星在轨稳定运行具有重要意义.本文基于某在轨卫星遥测数据，结合空间环境数据，应用LightGBM机器学习框架研究建立梯度提升决策树模型，对卫星飞轮温度进行预测.经与实际遥测温度值进行对比验证，预测精度可以满足对卫星飞轮温度的监视需求.研究结果可应用于地面系统，对卫星姿态控制系统可能发生的温度异常进行预警，使地面运控人员能够提前规避风险，保障卫星的安全在轨运行.      

The connection between space weather and Single Event Upsets in polar low earth orbit satellites

Space weather is driven and modulated by the activity in the Sun. Space weather events have the potential to inflict critical damage to space systems. Nowadays, space assets are essential in our basic needs, such as communications, cell phone networks, navigation systems, television and internet. Hence, understanding space weather dynamics and its effects on spacecraft is crucial for satellites engineers and satellite operators, in order to prevent and mitigate its impacts.In the last decade our Sun has erupted several times causing dozens of space weather events. Some of these led to satellite malfunctions and outages lasting from mere hours, up to days and weeks. This research is focused on two different space weather events, March 7–8, 2012, and September 6–10, 2017, that occurred during the last ten years and caused satellite anomalies that are related to an increase in the single event upsets rate. Single event upset is a bit flip in a memory device due to high energy particle interaction with the device sensitive volume. During these two periods, Eros B, a low Earth orbiting polar satellite detected an increased rate of single event upsets on two of its processing computers when the high energy proton flux was elevated. On both occasions X-class flares were detected, and the increased single event upsets count rate in Eros B took place only after the 100 MeV protons flux was three orders of magnitude above the background levels. In this research, Israeli satellite anomalies that were detected are first demonstrated.     

The use of Gaussian equations of motions of a satellite for local gravity anomaly recovery

The orbital elements of a low Earth orbiting satellite and their velocities can be used for local determination of gravity anomaly. The important issue is to find direct relations among the anomalies and these parameters. Here, a primary theoretical study is presented for this purpose. The Gaussian equations of motion of a satellite are used to develop integral formulas for recovering the gravity anomalies. The behaviour of kernels of the integrals are investigated for a two-month simulated orbit similar to that of the Gravity field and steady-state ocean circulation explorer (GOCE) mission over Fennoscandia. Numerical investigations show that the integral formulas have neither isotropic nor well-behaved kernels. In such a case, gravity anomaly recovery is not successful due to large spatial truncation error of the integral formulas. Reformulation of the problem by combining the orbital elements and their velocities leads to an integral with a well-behaved kernel which is suitable for our purpose. Also based on these combinations some general relations among the orbital elements and their velocities are obtained which can be used for validation of orbital parameters and their velocities.     

Electric field and ion density anomalies in the mid latitude ionosphere: Possible connection with earthquakes?

The problem of earthquake prediction has stimulated the search for a correlation between seismic activity and ionospherical anomalies. We found observational evidence of possible earthquake effects in the near-equatorial and low latitude ionosphere; these ionospheric anomalies have been proposed by Gousheva et al. [Gousheva, M., Glavcheva, R., Danov, D., Angelov P., Hristov, P., Influence of earthquakes on the electric field disturbances in the ionosphere on board of the Intercosmos-Bulgaria-1300 satellite. Compt. Rend. Acad. Bulg. Sci. 58 (8) 911–916, 2005a; Gousheva, M., Glavcheva, R., Danov, D., Angelov, P., Hristov, P., Kirov, B., Georgieva, K., Observation from the Intercosmos-Bulgaria-1300 satellite of anomalies associated with seismic activity. In: Poster Proceeding of 2nd International Conference on Recent Advances in Space Technologies: Space in the Service of Society, RAST ‘2005, June 9–11, Istanbul, Turkey, pp. 119–123, 2005b; Gousheva, M., Glavcheva, R., Danov, D., Angelov, P., Hristov, P., Kirov, B., Georgieva, K., Satellite monitoring of anomalous effects in the ionosphere probably related to strong earthquakes. Adv. Space Res. 37 (4), 660–665, 2006]. This paper presents new results from observations of the quasi-static electric field and ion density on board INTERCOSMOS-BULGARIA-1300 satellite in the mid latitude ionosphere above sources of moderate earthquakes. Data from INTERCOSMOS-BULGARIA-1300 satellite and seismic data (World Data Center, Denver, Colorado, USA) for magnetically quiet and medium quiet days are juxtaposed in time-space domain. For satellite’s orbits in the time period 15.09–01.10.1981 an increase in the horizontal and vertical components of the quasi-static electric field and fluctuations of the ion density are observed over zones of forthcoming seismic events. Some similar post effects are observed too. The emphasis of this paper is put on the anomalies which specify the mid latitude ionosphere. The obtained results contain important information because they confirm our previous results for near-equatorial and low latitude regions.     

Ground-based and satellite DC-ULF electric field anomalies around Wenchuan M8.0 earthquake

The ground-based and satellite DC-ULF electric field data were analyzed around Wenchuan M8.0 earthquake on May 12, 2008 in China. The results show that ground electric field anomalies occurred at 3 stations located to the north and south of the epicenter with the amplitude of 3–100 mV/km. The change shapes and their amplitude of ground electric field anomalies are different largely due to their individual underground layer conductivity, water level and so on. The analysis of long time series illustrates that the abnormal geoelectric field started since March 2008. Onboard the DEMETER satellite, the ULF waveforms of electric field were collected and processed by wavelet transform method. The disturbances in the ionosphere were about 3–5 mV/m at a frequency band lower than 0.5 Hz. When the ground and space electric field anomalies were compared, their occurrence time and spatial distribution points are consistent with each other, including the long time anomalies from March 2008 and the short term ones 1–2 days before the Wenchuan earthquake. Finally, the coupling mechanism was discussed.