Table of Content

    15 September 2009, Volume 29 Issue 5 Previous Issue    Next Issue
    Overview of Scientific Objectives of China-Russia Joint Mars Exploration Program YH-1
    Wu Ji;Zhu Guangwu;Zhao Hua;Wang Chi;Li Lei;Sun Yueqiang;Guo Wei;Huang Chengli
    2009, 29 (5):  449-455.  doi: 10.11728/cjss2009.05.449
    Abstract ( 2750 )   PDF (688KB) ( 1814 )   Save
    Mars has been one of the most interesting planets in the solar system for human beings due to its orbit characteristics and its geology, and the main attraction is the possibility to find life on it. Since the 1990s, many exploration missions have been sent to Mars. From the beginning of this century, many space power countries have announced their manned Mars program strategy. China was the fifth country in the world to launch its artificial satellite on its own, and the third country to have the ability to carry out independent manned space program. However, China is not a power at all in deep space exploration. To catch up, China and Russia have signed an agreement on a joint Mars exploration program by sending a Chinese microsatellite Yinghuo-1 (YH-1) with Russian's Phobos-Grunt mission. Once YH-1 is in orbit, it will not only carry out its own exploration mission but also conduct joint measurement with Russian Phobos-Grunt spacecraft. In this paper, the scientific background is reviewed, the scientific objectives of YH-1 are given, and the scientific payloads and operation considerations are also briefly described.
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    YH-1 Mars Probe's Key Technology and its Design Feature
    Chen Changya;Hou Jianwen;Zhu Guangwu
    2009, 29 (5):  456-461.  doi: 10.11728/cjss2009.05.456
    Abstract ( 2072 )   PDF (617KB) ( 1424 )   Save
    In this paper, the function and design as well as the key technologies (ultra-long-range communication technology, deep space exploration attitude determination and control technology, thermal control technology etc.) of China's first Mars probe are analyzed. The solutions of the key technologies are given after the analysis, and then the design features are summarized. Finally, the whole satellite of YH-1 has undergone tests under various experimental circumstances, including: vibration, noise, solar array deployment, illumination, leak detection, vacuum thermal testing and sophisticated power testing, etc. In all these tests, YH-1 behaves normally. This paper can provide a good reference for the following tasks related to the development and production of the probe and following missions.
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    Exploring the Plasma Environment of Mars
    Li Lei;Zhang Aibing;Kong Linggao;Wang Shijin;Sun Yueqiang;Zhu Guangwu
    2009, 29 (5):  462-466.  doi: 10.11728/cjss2009.05.462
    Abstract ( 2717 )   PDF (507KB) ( 1221 )   Save

    Despite more than 40 years of in situ measurement, we still do not have a complete survey of particles, fields in the near Mars space. The Sino-Russian Joint Mars-Phobos Exploration program provides unique opportunity to investigate the global structure of the solar wind and Mars interaction region. Mars orbiter, YH-1 will explore the Martian space environment, to determine characteristics in different regions and their evolution with solar wind conditions, and to investigate the water escape process related with solar wind forcing. For these purposes, YH-1 will carry a plasma package consisting of two identical ion analyzers, and one electron analyzer, which aim at monitoring the plasma with energy from 0.02 keV up to 10 keV, providing mass analysis of ions in the mass range from 1 to 44\,au with fast time and fine energy resolution. Together with the magnetic field experiment on board YH-1, the plasma package will be the first to give full insight into the local plasma characteristics near the planet, to determine the possible total ion escape rate (particles/s) for the major ion species. The scientific objectives of the plasma experiment, as well as design of the instrument are presented in the paper.

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    Martian Space Environment Magnetic Field Investigation---High Accuracy Magnetometer
    Zhou Bin;Zhao Hua;Wang Jindong;Chen Siwen;Liao Huaizhe;Zhu Guangwu;Wang Chi;Z hang Xin;Li Lei;Sun Yueqiang;Feng Yongyong;Zhou Jingxuan;Tao Ran
    2009, 29 (5):  467-474.  doi: 10.11728/cjss2009.05.467
    Abstract ( 2540 )   PDF (812KB) ( 1271 )   Save
    This paper presents the purpose, design and methods of the exploration of Martian Space Environmental Magnetic Field by Yinghuo-1 (YH-1). YH-1 is the first Chinese Martian Space Environment Exploration Orbiter, which would be launched with Russian spacecraft ``Phobos-Grunt'' in October, 2009, and will reach Mars orbit in September, 2010. The main scientific objectives of the YH-1 mission are related with Martian space magnetic field structure and dynamic processes, and a fluxgate magnetometer was considered to be one of the most import payloads in the YH-1 orbiter. The instrument is designed to work in harsh environment around Mars orbit and to collect high resolution data in operational orbit. Two three-component fluxgate type sensors are installed in one boom with separation distance of 45 cm, and gradiometer mode is used to minimize the remnant field of platform. The boom is located at the tip of the deployable solar panel, and the distance between the center of the spacecraft and the outer sensor is about 3.2 m. The operation temperature of YH-1 magnetometer sensors is expected in the range -130~+75°C and the dynamic range is ±256 nT in 16-bit resolution. With a very low noise level below 0.01 nT·Hz-1/2, this magnetometer can measure three-component magnetic field from DC to 10 Hz. The magnetometer will work together with a Plasma Package onboard this orbiter to complete exploration of Martian space environment. The total mass of this magnetometer package is about 2.5 ,kg, and power consumption is 6.8 W.
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    Joint Russian-Chinese Satellite-to-satellite Martian Radio Occultation Experiment
    Sun Yueqiang;Du Qifei;Zhu Guangwu;Wu Ji;Tao Peng;Bai Weihua;Zhao Hua;Hu Xiong;Wu Xiaocheng;Zheng Jianhua
    2009, 29 (5):  475-479.  doi: 10.11728/cjss2009.05.475
    Abstract ( 2637 )   PDF (492KB) ( 1463 )   Save
    Joint Russian-Chinese satellite-to-satellite Martian radio occultation experiment will be used to sound Martian ionosphere to derive electron density profiles. Compared with satellite-to-Earth radio occultation technique, satellite-to-satellite radio occultation technique has the better ability to receive higher signal-to-noise ratio radio signal and acquire more accurate profiles in a wider range (especially in areas of solar zenith angle of less than 43° and angle of larger than 138°. Joint Russian-Chinese satellite-to-satellite Martian radio occultation experiment is based on measurement of frequency shift between two radio signals penetrated the Martian ionosphere. The two coherent signals are irradiated from the transmitters. The frequencies of the signals are near 416.5 MHz and 833 MHz. The transmitters will be installed on Russian spacecraft Phobos-Grunt (FGSC) and the receivers will be installed on Chinese satellite YH-1. The relative frequency shift between two signals will reflect the property of Martian ionosphere.
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    Design of YH-1 Satellite Wide FOV Color Camera With its Ground-based Detection
    Cao Jianzhong;Guo Wei;Zhu Qing;Wang Weihua;Tang Yao;Wu Li;Zhang Haifeng
    2009, 29 (5):  480-485.  doi: 10.11728/cjss2009.05.480
    Abstract ( 1972 )   PDF (647KB) ( 1232 )   Save
    In this paper, the working principle, specifications, scheme and design result of the Wide FOV Color Camera of the YH-1 satellite are introduced. The static spatial resolution of the camera reaches 180 lp/mm and SNR is 34 dB in the laboratory before launching. According to the user's request, the images are generated by the camera with different manner: in the default working, the first and the second images are completed with the auto exposure algorithm, the others are got with the increased or decreased time of exposure from the second; while in the injected-instruction working, the other images are produced with the appointed time of exposure. For the sake of shooting the bright object in the dark background, experiments are carried out in the dark room and outdoor in night to get images of both a globe and the moon. And the images have been evaluated by the user. The result proved that the camera works well, the data format is correct, the exposure algorithm is successful, the quality of the camera is high, and the data can be collected and sent back correctly. Finally some main technologies applied during the manufacturing process are introduced.
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    Design of YH-1 Payload Data Handling Unit
    An Junshe;Chen Xiaomin;Shi Junfeng;Zhou Shengyu;Wu Qi;Lv Liangqing;Zhang Zhongwei
    2009, 29 (5):  486-489.  doi: 10.11728/cjss2009.05.486
    Abstract ( 2873 )   PDF (572KB) ( 1288 )   Save
    According to the request of Payloads, it is necessary to design a safe and reliable Payload Data Handling Unit (PDHU) for YH-1 satellite. The functions of PDHU are data collection, data processing, data storage and system power supply. PDHU affords an operating system, which is convenient for software development. Under the circumstances of Mars exploration, a channel encoding method which adopts the non-interlaced RS-Convolutional Concatenated Code is used to ensure the communication between the space and the Earth.
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    Deep Space TT&C Equipments of YH-1
    Xiong Weiming;Xie Chunjian;Liang Xianfeng;Bai Yunfei;Qu Chenyang;Wang Zhugang;Guo Lili;Geng Hao;Deng Yongsheng;Jiang Yaxiang;Wang Wei;Cao Zhiyu;Zhao Tao
    2009, 29 (5):  490-494.  doi: 10.11728/cjss2009.05.490
    Abstract ( 2687 )   PDF (554KB) ( 1324 )   Save
    A new upsurge of deep space exploration has arisen internationally during the 21th century. The TT&C (Tracking, Telemetry, Control ) technologies of deep space are very important. The YH-1 microsatellite is the first deep space explorer of China. In this article, the deep space TT&C characteristics, the key technologies of the YH-1 TT&C sub-system are introduced. The configuration and technical performance are provided concisely. The functions of TT&C for YH-1 microsatellite are: the telemetry link (downlink: from the microsatellite to the ground station) that transmits engineering data (spacecraft and instrument health and status measurements) and science data (including image data); the telecommand link (uplink: from the ground station to the microsatellite) that transmits the control information and commands to the microsatellite. The orbit parameters can be measured by one-way tracking, one-way Doppler frequency and VLBI. The microsatellite TT&C is working of X-band. In order to simplify the TT&C sub-system of the microsatellite, a transmitter and a receiver are used, instead of a transponder. The TT&C equipments onboard are designed with redundancy, which total weight is about 10kg.
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    Anisotropy Analyses of Cosmic Ray Before the Geomagnetic Storm on Sep. 24, 1998
    Wang Jing;Liu Siqing;Xue Bingsen;Gong Jiancun
    2009, 29 (5):  495-501.  doi: 10.11728/cjss2009.05.495
    Abstract ( 2405 )   PDF (724KB) ( 1276 )   Save
    Cosmic rays are energetic particles originating from outer space that impinge on Earth's atmosphere. Almost 90\% of all the incoming cosmic ray particles are protons, about 9\% are helium nuclei and about 1\% are electrons. The nuclei that make up cosmic rays are able to travel from their distant sources to the Earth because of the low density of matter in space. Nuclei interact strongly with other matter, so when the cosmic rays approach Earth they begin to collide with the nuclei of atmospheric gases. These collisions, in a process known as shower, result in the production of many pions and kaons, unstable mesons which quickly decay into muons. Muons are ionizing radiation, and may easily be detected by many types of particle detectors such as bubble chambers or scintillation detectors. Based on the muon measurement data of 30°, 49°, 64° of East, West, South, North components of cosmic ray from Nagoya station, the north-south and west-east anisotropy of cosmic ray just before geomagnetic disturbances and quiet days is analyzed by use of Haar wavelet. It was found that fluctuations of the anisotropy of cosmic ray before geomagnetic disturbances increased due to the approaching of CME because the shock front and strong IMF induced by CME and the coefficient of wavelet always increased monotonously more than 10 hours ahead the geomagnetic storm, which hopefully could be the premonitory properties of the eruption of severe geomagnetic storm.
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    A New Method of Predicting the Ionospheric F2 Layer in the Asia Oceania Region
    Cao Hongyan;Sun Xianru
    2009, 29 (5):  502-507.  doi: 10.11728/cjss2009.05.502
    Abstract ( 2042 )   PDF (515KB) ( 2737 )   Save
    The new method of predicting the ionospheric F2 layer in the Asia Oceania region is based on cross-correlation theory of ionospheric parameters and the twelve-month running mean of sunsport number (R12). The R12 is substituted for the ionospheric prediction index Ic produced from f0F2 of Chongqing, and the B coefficients interpolated by three different R12 data are not used, which can reduce the error caused by converting R12 into Ic. Lots of data at several sounding stations have been prudently selected and suplemented based on the old predicting method, and the $ B$ coefficients needn't be computed any more, which can avoid interpolation error resulting from the intermediate link. A comparison of several predicting results shows that the new edition is much more accurate.
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    Spacecraft Relative Positioning Using X-ray Source
    Mao Yue;Song Xiaoyong;Jia Xiaolin;Wu Xianbing
    2009, 29 (5):  508-514.  doi: 10.11728/cjss2009.05.508
    Abstract ( 2009 )   PDF (615KB) ( 1004 )   Save
    The basic principles of spacecraft relative positioning using X-ray source are presented in this paper. This method can break through the restriction of X-ray pulsar absolute positioning which must select steady periodical pulsars. Time differences are simulated using cross-correlation periodic pulse signal and aperiodic changing signal. Results can be derived from the fact that the change amplitude of signals has significant influence on the precision of time difference measurement. The influences of range and ephemeris error on position precision are analyzed. Relative positioning precisions are calculated by simultaneously observing three to six pulsars which parameters are taken from the pulsar database.
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    CDGPS Relative Position Determination of Distributed SAR Satellite Formation Based on Dynamic Orbit Model
    Gu Defeng;Zhu Shubo;Yi Dongyun
    2009, 29 (5):  515-521.  doi: 10.11728/cjss2009.05.515
    Abstract ( 2110 )   PDF (672KB) ( 1214 )   Save
    To determine the baseline of distributed SAR satellite formation at high accuracy, a CDGPS relative position method of distributed SAR satellite formation based on dynamic orbit model is presented. At first, CDGPS principle is introduced. And then, intersatellite relative position method based on dynamic orbit model is introduced. Based on CDGPS measurement, this method introduces prior restricted information provided by dynamic orbit model, and overcomes the disadvantage that kinematic single point position determination can not be used when observation geometry is bad or observations are not enough. This method can restrain the random errors in measurement, improve relative position accuracy and provide a technology approach to realize intersatellite baseline determination at mm level. At last, simulation computation verifies the efficiency of the dynamic method. Computational results show that the dynamic method can improve the relative position accuracy remarkably. Compared with kinematic method, the fixed solution accuracy of L1 is improved by 68%, and the fixed solution accuracy of ionosphere free combination is improved by 95%.
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    Spacecraft Task Hierarchical Scheduling Analysis Within Fixed Priorities
    He Feng;Song Liru;Xiong Huagang
    2009, 29 (5):  522-528.  doi: 10.11728/cjss2009.05.522
    Abstract ( 2020 )   PDF (526KB) ( 1194 )   Save
    In the autonomous control architecture for spacecraft, layered structure style is adopted. It manages all categorical applications through partition management to avoid interaction among them. This paper focuses on the partition schedulablity analysis and the partition design for fixed priorities scheduling model. It introduces a more exact partition task worst-case response time algorithm through observing the actually iterative operator, and addresses a partition designable condition based on the upper limit of the task utilization factor within the fixed priorities. By using the cost function, it also proposes the partition key parameters resolution model and a local optimal algorithm to implement the whole processor partition design. At last, it introduces a practical example to illustrate the validity of the analysis and design methodology.
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    Theoretical Analysis of Surface Error for Deployable Truss Antenna
    Yang Yulong;Guan Fuling
    2009, 29 (5):  529-533.  doi: 10.11728/cjss2009.05.529
    Abstract ( 2419 )   PDF (463KB) ( 1194 )   Save
    Aimed at the characteristics of large deployable truss antenna with many trusses and joints, surface error and repetitive deployable precision of antenna with tolerances of trusses and joints clearances were studied. Considered the randomicity of tolerances of trusses and joints clearances, a stochastic finite element model of deployable truss antenna used Monte-Carlo method was developed to simulate the root mean square of surface error. It is shown that the value of root mean square of surface error caused by joints clearances is much larger than that from tolerances of trusses, and the repetitive deployable precision error of antenna can not be neglected.
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    Reflector and Thermal Analysis of Plan-parabolic Membrane Antenna
    Xu Yan;Guan Fuling;Wang Hongjian
    2009, 29 (5):  534-539.  doi: 10.11728/cjss2009.05.534
    Abstract ( 1990 )   PDF (517KB) ( 1179 )   Save
    To solve the problem between limited volume of the rocket mantles and large caliber requirement of antenna and the problem between carrying capacity of rocket and large weight of antenna, the inflatable antenna structure technology is one of the best choices. Afterward, to obtain high precision of inflatable reflector, one of figuration theories which is titled as plan-parabolic reflector, was investigated. The elastic theory analysis was carried out and the relationship between reflector shape and inflatable pressure, material, boundary condition is obtained. There is M shape error between reflector shape and parabolic. Based on these works, the influence that temperature variety affects on the reflector precision on orbit was studied and methods to eliminate this effect are discussed. The analyze result from ANSYS software is compared with the result from this paper and the validity of analysis method is clarified.
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    Extended Research of the Geometric Dilution of Position in Pseudo-distance Navigation System
    Huang Ying
    2009, 29 (5):  540-544.  doi: 10.11728/cjss2009.05.540
    Abstract ( 2002 )   PDF (354KB) ( 1178 )   Save
    The GDOP is an important parameter in the navigation system. Yet, along with the development of navigation system from single mode to integrated modes, different systems were integrated into a composed mode system, which resulted in difficult definition and calculation of GDOP and restricted its applications. Based on numerical computation of GDOP, the paper converts the calculation into resolution of different linear equations. The different systems are considered as different restricted conditions. This new method successfully resolved the problem, which could improve the application of the GDOP.
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