卫星磁载荷现场校准技术研究

本文介绍了一种卫星磁场探测载荷现场校准技术,设计了拆分式磁场线圈、无磁支架等,研制了校准装置。利用该技术实现了对卫星磁载荷在整星测试、发射前等多个阶段的测试校准,解决了卫星载荷在星体装配完成后无法测试的难题,提高了磁载荷测试数据可靠度,保证了科学实验的有效性。该校准技术已服务于我国首颗地磁监测试验卫星(张衡一号卫星),对其磁场探测载荷在整星测试、出厂测试、发射场技术确认等多个阶段进行了校准,取得了很好的应用效果。     

卫星磁载荷现场校准技术研究

本文介绍了一种卫星磁场探测载荷现场校准技术，设计了拆分式磁场线圈、无磁支架等，研制了校准装置。利用该技术实现了对卫星磁载荷在整星测试、发射前等多个阶段的测试校准，解决了卫星载荷在星体装配完成后无法测试的难题，提高了磁载荷测试数据可靠度，保证了科学实验的有效性。该校准技术已服务于我国首颗地磁监测试验卫星（张衡一号卫星），对其磁场探测载荷在整星测试、出厂测试、发射场技术确认等多个阶段进行了校准，取得了很好的应用效果。     

电磁监测试验卫星矢量磁场探测方法

电磁监测试验卫星是中国第一颗近地轨道电磁场科学探测试验卫星, 探测空间背景磁场是其重要任务之一. 空间背景磁场探测需要在卫星平台上对空间矢量磁场进行长期稳定准确探测, 电磁监测试验卫星采用磁通门磁强计和基于CPT效应的绝对磁场校准装置(Coupled Dark State Magnetometer, CDSM)分别探测空间相对矢量磁场以及绝对标量磁场, 通过数据处理, 使最终的矢量磁场探测数据具有准确性. 这种数据处理方法在理想模型下拥有解析解, 实施过程中载荷的噪声、 准确度及稳定性影响模型的准确性, 会产生数据校准误差. 通过对在轨磁场探测的模拟确定了这种数据处理方法的性能, 验证了在载荷设计性能的基础上电磁监测试验卫星的磁场探测可以实现1 nT的准确度.      

DEMETER卫星记录到的电离层加热现象

在法国DEMETER卫星运行期间, 地基电离层加热装置SURA和HAARP开展了一系列加热试验, 记录到各类电离层异常信息, 发现电离层加热过程中卫星观测的电离层扰动信号包括HF发射泵波及边带泵波、VLF人工源增强及频谱拓展、ULF/ELF/VLF调制波、ELF电磁扰动、ULF谐振波、等离子体特征参量扰动及高能粒子沉降等. 由于传播及耦合机制的差异, 发射泵波可以穿透电离层直达卫星高度, 其观测概率最高达到68%以上, 其他扰动受发射调制模式及当地电磁环境等影响,观测概率相对较低, 均在40%左右, 有些甚至是某次试验中出现的个别事例. 结合中国地震电磁监测试验卫星飞行轨道设计及载荷配置等,对未来开展加热试验进行了分析论证, 并参考DEMETER卫星试验结果给出了一些建议.      

Quantum Science Satellite

Quantum Science Satellite is one of the first five space science missions, slated for launch in the framework of Chinese Academy of Sciences (CAS) Strategic Priority Research Program on space science. The project aims to establish a space platform with long-distance satellite and ground quantum channel, and carry out a series of tests about fundamental quantum principles and protocols in space-based large scale. The satellite will be launched at Jiuquan and on orbit for 2 years. The orbit will be circular and Sun-synchronous with an altitude of 600km. It crosses the descending node at 00:00LT. The satellite is under early prototype development currently.      

GPS定位数据在海洋一号卫星中的应用与比较

简要介绍了海洋一号卫星星载GPS接收机的定位原理、流程和应用，探讨了一种在轨定位结果的确认和互验方法．借助于卫星工具包软件(STK)，利用NASA网站公布的HY-1卫星两行根数(TLE)进行卫星轨道推算，生成星下点位置，并与相应时刻星载GPS接收机实测数据得到的星下点位置进行比较，由此得到两种方法定位结果之间的偏差，用实际在轨数据验证了两者的位置符合程度．     

Fengyun Satellites: Achievements and Future

Chinese meteorological satellite, Fengyun (FY) Satellite, has a polar-orbiting series and a geostationary series. Up to now, 5 polar-orbiting (FY-1A/B/C/D and FY-3A) and 5 geostationary (FY-2A/B/C/D/E) satellites were launched. FY data has been being intensively applied not only to meteorological monitoring and prediction but also to many other fields regarding ecology, environment, disaster, space weather and so and. The FY data sharing system, FengyunCast, is now one of the three components of global meteorological satellite information dissemination system, GEONETCast. The first satellite of the new generation polar-orbiting series, FY-3A, was launched on 27 May, 2008, demonstrating the FY polar-orbiting satellite and its application completed a great leap to realize three-dimensional observations and quantitative application. The first of the next generation geostationary series (FY-4) is planned to launch in 2014.      

GRO和LRO掩星事件模拟研究

GRO（Global Navigation Satellite System Radio Occultation）和LRO（Low Earth Orbit Radio Occultation）联合组网探测地球大气是无线电掩星探测技术的主要发展方向.本文根据掩星事件的数学判据,仿真分析了LEO卫星主要轨道参数对GRO和LRO掩星事件数量和全球分布情况的影响.研究表明:卫星轨道越低GRO掩星事件越多;轨道倾角在30°和75°之间时,GRO掩星事件较多,全球覆盖率也较大;利用极轨卫星进行LRO掩星探测时,LRO掩星事件较均匀地分布在各纬度带.研究成果对GRO和LRO联合星座设计具有参考价值.      

Recent Progress of Fengyun Meteorology Satellites

After nearly 50 years of development, Fengyun (FY) satellite ushered in its best moment. China has become one of the three countries or units in the world (China, USA, and EU) that maintain both polar orbit and geostationary orbit satellites operationally. Up to now, there are 17 Fengyun (FY) satellites that have been launched successfully since 1988. There are two FY polar orbital satellites and four FY geostationary orbit satellites operate in the space to provide a huge amount of the earth observation data to the user communities. The FY satellite data has been applied not only in the meteorological but also in agriculture, hydraulic engineering, environmental, education, scientific research and other fields. More recently, three meteorological satellites have been launched within the past two years. They are FY-4A on 11 December 2016, FY-3D on 15 November 2017 and FY-2H on 5 June 2018. This paper introduces the current status of FY meteorological satellites and data service. The updates of the latest three satellites have been addressed. The characteristics of their payloads on-boarding have been specified in details and the benefit fields have been anticipated separately.      

中国的返回式卫星

中国的返回式卫星是一种低轨道、三轴稳定、返回舱可安全回收的卫星,可用作遥感卫星、微重力试验平台和科学技术试验卫星。文章简要地概述了卫星的各分系统,卫星的发射和返回以及卫星的主要应用方面。到1990年,我国已发射成功和回收了12颗返回式卫星,取得了比较好的社会效益和经济效益。     

Progress of the Quantum Experiment Science Satellite(QUESS) Micius Project

By using satellites, ultra-long-distance quantum communication and tests of quantum foundations could be achieved at a global scale. The Quantum Experiment Science Satellite (QUESS) in China, also called Micius, one of the scientific satellite programs in the Strategic Priority Program on space science, the Chinese Academy of Sciences, was launched on 16 August 2016. There are totally 4 scientific payloads. We give a brief overview of the quantum experiment science satellite project and present most recent science results. The main scientific goal of the quantum experiment science satellite was achieved in 2017. Here, we introduce the latest achievements in satellite-based quantum communication and large-scale tests of quantum foundations obtained by Micius.      

The Experimental Satellite on Electro-magnetism Monitoring

The Experimental Satellite on Electromagnetism Monitoring (ESEM) was proposed in 2003 and proved in 2013 after 10-years' scientific demonstration. The ESEM mission was proposed to be the first satellite of space-based geophysical fields observation system in China with a lot of application prospects in earthquake science, geophysics, space sciences and so on. And coincide with the mission objectives, the satellite decides to use the Circular Sun Synchronous Orbit with an altitude of 507km and descending node time at 14:00LT. The payload assemble includes 8 instruments, Search-Coil Magnetometer, Electric Field Detector, High precision Magnetometer, GNSS occupation Receiver, Plasma Analyzer, Langmuir Probe, Energetic Particle Detector, and Three-frequency Transmitter. According to the planned schedule, the satellite is due to be launched in 2016-2017 and will be onboard operated for 5 years.      

中国航天器工程的成就与展望

中国航天器工程 40多年来经历了技术准备阶段、技术试验阶段和工程应用阶段 ,已形成了返回式遥感卫星系列 ,通信广播卫星系列 ,气象卫星系列和科学探测与技术试验卫星系列 ,而地球资源卫星系列和导航定位卫星系列也即将形成 ;至今中国已发射成功人造地球卫星 5 1颗 ,发射成功试验载人飞船 4艘 ,取得了举世瞩目的成就 ,为国民经济、国防建设、文化教育和科学研究作出了重大的贡献。进入 2 1世纪 ,根据中国航天近期和远期的发展目标 ,中国航天器工程将迎来新的辉煌     

Potentials for radio occultation applications during inter-satellite calibration periods

EUMETSAT has launched the first in a series of three Metop satellites in October 2006. Each satellite has a nominal 5 year life time, covering 14 years in total. Successive satellites will be launched with about 0.5 year overlap into the same sun-synchronous polar orbit, allowing inter-satellite calibration.     

Improved kHz-SLR tracking techniques and orbit quality analysis for LEO missions

Satellite gravity field missions such as CHAMP, GRACE and GOCE are designed as low Earth orbiting spacecraft (LEO) with orbit heights of about 250–500 km. The challenging mission objectives require a very precise knowledge of the satellite orbit position in space. For these missions precise orbit information is typically provided by GPS satellite-to-satellite tracking (SST) observations supported by satellite laser ranging (SLR).     

Impact of GPS antenna phase center variations on precise orbits of the GOCE satellite

The first European Space Agency Earth explorer core mission GOCE (Gravity field and steady-state Ocean Circulation Explorer) has been launched on March 17, 2009. The 12-channel dual-frequency Global Positioning System receiver delivers 1 Hz data and provides the basis for precise orbit determination (POD) on the few cm-level for such a very low orbiting satellite (254.9 km). As a member of the European GOCE Gravity Consortium, which is responsible for the GOCE High-level Processing Facility (HPF), the Astronomical Institute of the University of Bern (AIUB) provides the Precise Science Orbit (PSO) product for the GOCE satellite. The mission requirement for 1-dimensional POD accuracy is 2 cm. The use of in-flight determined antenna phase center variations (PCVs) is necessary to meet this requirement. The PCVs are determined from 154 days of data and the magnitude is up to 3-4 cm. The impact of the PCVs on the orbit determination is significant. The cross-track direction benefits most of the PCVs. The improvement is clearly seen in the orbit overlap analysis and in the validation with independent Satellite Laser Ranging (SLR) measurements. It is the first time that SLR could validate the cross-track component of a LEO orbit.     

East–West Station-Keeping maneuver strategy for COMS satellite using iterative process

The first Korean multi-mission geostationary satellite, Communication, Ocean, and Meteorological Satellite (COMS) will be launched in 2010. The missions of this satellite will be Ka-band communications, ocean color monitoring, and meteorological imaging. The satellite was designed with only one solar array on the south panel. This novel configuration will keep imaging instruments on the north side from heating up. Asymmetry of the spacecraft configuration requires twice-a-day thruster-based Wheel Off-Loading (WOL) operations to keep the satellite attitude for imaging and communication. Thruster firings during the WOL operations cause the satellite orbit to change two times a day. Weekly East–West Station-Keeping (EWSK) and North–South Station-Keeping (NSSK) maneuver operations are planned for the COMS satellite in order to maintain the satellite in ±0.05° box at 128.2°E longitude.     

Experiment VARIANT – first results from Wave Probe instrument

The international experiment VARIANT was carried out onboard Ukrainian remote sensing satellite SICH-1M launched 2004, December 24. In spite of other than planned satellite orbit and onboard systems failure about 11 telemetric files from VARIANT payload were obtained. Due to episodic and random payload switching the main goal of VARIANT experiment - study of field aligned currents and monitoring of electromagnetic state of the ionosphere – was not possible to realize. However the data analysis from VARIANT instrumentation allowed us to obtain for the first time a reliable confirmation of proper operation in ionospheric plasma of a new device developed for wave activity study – Wave Probe, which consists of compact combination of Split Langmuir Probe working at floating potential and search-coil magnetic field sensor. Such a probe can simultaneously measure variations of one component of spatial current density and a perpendicular component of magnetic field with a spectral sensitivity threshold up to 0.1 pA/(cm² Hz^1/2) and 0.03 pT/Hz^1/2, respectively.     

Update on Fengyun Meteorological Satellite Program and Development

China began to develop its meteorological satellite program since 1969. With 50-years' growing, there are 17 Fengyun (FY) meteorological satellites launched successfully. At present, seven of them are in orbit to provide the operational service, including three polar orbiting meteorological satellites and four geostationary meteorological satellites. Since last COSPAR report, no new Fengyun satellite has been launched. The information of the on-orbit FY-2 series, FY-3 series, and FY-4 series has been updated. FY-3D and FY-2H satellites accomplished the commission test and transitioned into operation in 2018. FY-2E satellite completed its service to decommission in 2019. The web-based users and Direct Broadcasting (DB) users keep growing worldwide to require the Fengyun satellite data and products. A new Mobile Application Service has been launched to Fengyun users based on the cloud technology in 2018. In this report, the international and regional co-operations to facilitate the Fengyun user community have been addressed especially. To strengthen the data service in the Belt and Road countries, the Emergency Support Mechanism of Fengyun satellite (FY_ESM) has been established since 2018. Meanwhile, a Recalibrating 30-years' archived Fengyun satellite data project has been founded since 2018. This project targets to generate the Fundamental Climate Data Record (FCDR) as a space agency response to the Global Climate Observation System (GCOS). At last, the future Fengyun program up to 2025 has been introduced as well.      

Comparison of electron density measurements from CSES and Swarm satellites with GNSS ionospheric tomography data

Electron density measurements obtained from China Seismo‐Electromagnetic Satellite (CSES) and Swarm-B can play an increasingly important role in the study of ionosphere above F2 peak height. This study presented a comprehensive comparison of electron density products obtained from Langmuir probe mounted on CSES and Swarm-B with ionospheric tomography for a whole year period of 2019. CSES was fully compared with Swarm-B on a global scale, including both absolute and relative differences, and a new index called NFI was developed to better quantify the similarity between two latitudinal profiles of electron density. CSES and Swarm-B were then compared with tomography respectively in four regions, roughly located in America, Europe, Australia and China. Results indicated that CSES data are consistent with Swarm-B, as NFI values exceed 0.6 for most of the analyses. Tomography and Swarm-B were found to have a good agreement as their biases are less than 0.2 × 10⁵ el/cm³ in general. For the comparison between CSES and tomography, the bias increased to around 0.6 × 10⁵ el/cm³ but the standard deviation changed slightly, validating the underestimation of electron density by CSES. The spatiotemporal comparisons of CSES and Swarm-B with tomography showed that: 1) the differences in electron density were relatively low in middle latitudes and increased rapidly in the regions of equatorial ionization anomaly; 2) Swarm-B has a better consistent with tomography than CSES, but both are capable of detecting ionosphere anomalies such as midlatitude arcs; and 3) CSES and Swarm-B both can capture the seasonal changes of electron density, while their values are basically smaller than those from tomography in Spring and Summer months.