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    Research on CEI phase delay resolving method for BDS GEO satellite
    CHEN Shaowu, WANG Jingwen, HUANG Lei, XU Dezhen
    Chinese Space Science and Technology    2020, 40 (6): 123-130.   DOI: 10.16708/j.cnki.1000-758X.2020.0079
    Abstract531)      PDF(pc) (3537KB)(317)      
    Connected element interferometry (CEI) is a precision angular measurement technology widely used in the orbit determination of MEO satellites, GEO satellites, lunar probes and deep space probes. A new measurement mode was proposed based on the characteristics of CEI. The carrier and ranging signals in coherent ranging mode were used in CEI. A CEI system was established and used to observe BDS (BeiDou navigation satellite system) GEO satellite. Group delay and phase delay were calculated by using all these signals. Group delay and phase delay results of the BDS GEO satellite were estimated by using the theoretical delay values calculated by precision ephemeris. The results show that the means of the residual of group delay and phase delay is 0.47ns and 0.08ns, and that the standard deviation (3σ) of the residual of group delay and phase delay is 4.2ns and 0.13ns. The feasibility of the phase delay calculation of CEI in coherent ranging mode is verified. This paper can provide reference for precision orbit determination of co-location GEO satellites, lunar probes and deep space probes.
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    Error analysis and prediction of Klobuchar ionospheric model 
    PENG Yaqi, LI Chonghui, WANG Yiwen, WEI Wulei, DING Baichao, LIU Yangqian
    Chinese Space Science and Technology    2021, 41 (1): 48-54.   DOI: 10.16708/j.cnki.1000-758X.2021.0006
    Abstract359)      PDF(pc) (5519KB)(135)      
     Ionospheric delay error is one of the most important error sources in global navigation satellite system (GNSS). At present, the most widely used ionospheric delay correction model is the Klobuchar parameter model, but the correction rate of this model can only reach about 60%, which cannot meet the increasing accuracy requirements. The high-precision ionospheric grid data published by the international GNSS monitoring & assessment system (iGMAS) were used as a reference value to calculate and analyze the error of Klobuchar ionospheric model. The results show that the error in the mid latitude region has obvious periodic characteristics. To further improve the correction accuracy of the Klobuchar ionosphere model in the mid-latitude region, a Klobuchar ionospheric error prediction model was established based on particle swarm optimization back propagation (BP) neural network. Error prediction was made by taking the sample data of October 2019 as an example. The results show that accuracy can be improved to about 90% by using the model to compensate for the ionospheric delay error in the mid latitude region.
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    Research on performance evaluation of small reconnaissance satellite constellation
    WANG Hao, ZHANG Zhanyue, ZHANG Haitao, JIANG Ping
    Chinese Space Science and Technology    2020, 40 (6): 68-76.   DOI: 10.16708/j.cnki.1000-758X.2020.0073
    Abstract300)      PDF(pc) (1730KB)(176)      
    To evaluate small reconnaissance satellite constellation′s performance, some performance indexes were studied from three aspects: coverage, cost and flexibility. The coverage capability evaluation model, cost estimation model and flexibility capability evaluation model were built. In the coverage capability evaluation model, satellite storage capacity was taken as a constraint condition, satellite working conditions were analyzed by combining with the satellite coverage geometry model, and a calculation method of coverage indexes considering satellite storage capacity was proposed. The cost of each subsystem of constellations was estimated by the small satellite cost model(SSCM). In the flexibility evaluation model, the performance loss rate was proposed, and the weight of performance loss rate was determined according to the probability function of failure states. Applying the models to the performance evaluation of SkySat and Jinlin No.1 (JL-1) constellation, the results show that SkySat constellation has stronger coverage ability, lower cost and poorer flexibility than those in JL-1. The above models proposed in this paper can be used to evaluate the advantages and disadvantages of constellations and provide references for the construction and performance evaluation of small reconnaissance satellite constellation.
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    Fault diagnosis and fault tolerant control of spacecraft attitude control system via deep neural network
    GENG Feilong, LI Shuang, HUANG Xuxing, YANG Bin, CHANG Jiansong, LIN Bo
    Chinese Space Science and Technology    2020, 40 (6): 1-12.   DOI: 10.16708/j.cnki.1000-758X.2020.0066
    Abstract298)      PDF(pc) (4795KB)(264)      
    In order to solve the problem of low diagnosis accuracy and control allocation efficiency of traditional fault diagnosis and faulttolerant control methods, this paper proposes a new method of fault diagnosis and fault tolerance control for spacecraft attitude control system based on deep neural network. Taking the control moment gyroscopes as actuator, the method can achieve robust attitude control when the actuator fails. First, we use three heterogeneous deep neural networks to achieve the functions of fault diagnosis, attitude control and torque distribution of traditional faulttolerant controllers, and the intelligent adaptive faulttolerant controller architecture of full neural networks is established. Then, the parameters of the three neural networks such as the number of network layers, the number of neurons and activation functions are optimized and adjusted, and the influence of the parameters of the neural network on the performance of the controller is compared and analyzed. Numerical simulation is conducted to prove that the proposed new controller has good control accuracy and robustness when the control moment gyroscopes fail. The simulation results show that for the spacecraft with a redundant control moment gyroscope, the method proposed in this paper can not only achieve highprecision faulttolerant control under single gyro failure, but also ensure a certain attitude stability control when multiple gyroscope failures occur.
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    Design and trial of extraterrestrial artificial photosynthesis device
    FENG Deqiang, ZHANG Ce, JIANG Wenjun, LI Long, YANG Dongsheng, LAI Xiaoming, SONG Jian, YAO Wei
    Chinese Space Science and Technology    2020, 40 (6): 13-22.   DOI: 10.16708/j.cnki.1000-758X.2020.0067
    Abstract272)      PDF(pc) (6062KB)(131)      
    In-situ resource utilization (ISRU) technology is a promising process for recycling extraterrestrial resources and constructing life support system to realize survival in extraterrestrial environment. ISRU has been the core technology in human deep space exploration. Based on the microchannel technique, a flow reactor was designed to simulate artificial photosynthesis in microgravity and other special environmental conditions as well as to realize the conversion of carbon dioxide to oxygen and hydrocarbons. The microchannel based reactor can accelerate the products of the gas-liquid reaction from the electrode surface with the reaction medium by the sheer force. Theoretically, it can overcome the influence of microgravity conditions on the reaction process, which needs to be verified by microgravity experiments in future. Simultaneously, the optimized reaction conditions can be obtained in the microchannel structure by precisely controlling the pressure, flow rate and ratio of input gas to liquid. Based on the artificial photosynthesis reactor, an extraterrestrial artificial photosynthesis device was developed, which integrated the reaction module, control module, flow drive module and detection module. The feasibility of the reactor in reducing carbon dioxide to oxygen and carbonaceous compound (CO) was verified by ground experiment. With Au and Ir/C as the catalytic cathode and anode electrode respectively, the evaluation rate of O2 can reach 11.74 mL/h under 3 V applied voltage. This device possesses multifunction of in-situ physicochemical reaction, medium supply, precise control, products collection and analysis. And this device can implement effective conversion of carbon dioxide and oxygen generation. The work provides a theoretical and practical foundation for subsequent device optimization, carbon dioxide conversion to variable hydrocarbon products with high selectivity, and on-orbit test of artificial photosynthesis device.
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    Characteristics analysis of hybrid propulsion geostationary orbit
    DUAN Xiaowen, QI Rui, WANG Min
    Chinese Space Science and Technology    2020, 40 (6): 48-55.   DOI: 10.16708/j.cnki.1000-758X.2020.0071
    Abstract264)      PDF(pc) (6707KB)(158)      
    Taking the transfer orbit design of the geosynchronous orbit satellite as mission background, the hybrid chemical electric propulsion orbit transfer was designed and analyzed to address the problems of great fuel consumption of fully chemical propulsion and long transfer time of fully electric propulsion.  Firstly, the influence of inclination and argument of perigee of switching orbit on transfer performance was analyzed. Analysis indicates that inclination should be used as one of the optimization variables. Secondly, the perigee radius, apogee radius and inclination of the switching orbit were used as optimization variables to construct the search grid. Each point in the grid corresponded to one switching orbit. For each switching orbit, a chemical propulsion orbit segment and an electric propulsion orbit segment were computed separately. The chemical propulsion segment was achieved by Lambert transfer, and the electric propulsion segment was achieved by using hybrid method for optimization. Finally, taking fuel consumption and transfer time as design index, exhaustive search for the switching orbits in the search grid was implemented, and the trend of hybrid propulsion transfers in the entire solution space was analyzed. The method proposed provides a family of solutions, filling the gap between the fully chemical transfer solution and fullyelectric transfer solution. The solutions have different combinations of fuel consumption and transfer time, and can be used in future missions.
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    Control method for variable skew configuration control moment gyros
    ZHANG Kebei, GAO Jingmin, GUAN Xin, GUO Zixi
    Chinese Space Science and Technology    2020, 40 (6): 23-32.   DOI: 10.16708/j.cnki.1000-758X.2020.006
    Abstract261)      PDF(pc) (9440KB)(180)      
    The momentum envelope of fixed skew configuration control moment gyroscopes (CMGs) cannot be changed flexibly to meet the different satellite attitude maneuver requirements. The control method for variable skew configuration CMGs was designed. The dynamic model of the variable skew configuration CMGs was established. Considering multiple control variables, such as gimble rate, highspeed rotor speed and skew angle rate, the steer control law of the variable skew configuration CMGs was designed. The momentum envelope of CMGs and singular state distribution were analyzed. The variable skew configuration CMGs were used to achieve the satellite threeaxis attitude agile maneuver control. The simulation results show that the control method for the variable skew configuration CMGs can realize the satellite threeaxis attitude agile maneuver control with different number of CMG faults
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    Technical project of ion propulsion for satellites in super low Earth orbit 
    YANG Fuquan, WANG Chengfei, HU Jing, ZHANG Hong, WU Chenchen, ZHANG Xingmin, GENG Hai, FU Danyin
    Chinese Space Science and Technology    2021, 41 (3): 52-59.   DOI: 10.16708/j.cnki.1000.758X.2021.0038
    Abstract256)      PDF(pc) (3138KB)(234)      
    The Earth's outer atmosphere at the low altitude causes a significant drag on the spacecraft such as scientific detection and Earth observationsatellites in super low earth orbit, furthermore the atmospheric drag changes in a wide range along with solar activity, geomagnetic activity, seasonal and diurnal cycle. In order to meet the demands for satellite orbit accuracy or flight conditions, this drag needs to be continuously or intermittently compensated by onboard thrusters. Considering drag free flight and orbit maintenance at an altitude of about 220~268km, the variety of atmospheric drag and the specifications of the spacecraft payloads were analyzed, and then the researches were carried out on the technical parameters, thrust throttling approaches, system architecture, thrust control project and onorbit application strategy of ion propulsion. Accordingly thrust throttling tests were executed .The results show that ion propulsion should operates over a thrust range of 1~20mN with the thrust resolution of 12μN, and over a thrust range of 1~25mN with the thrust resolution of 100μN for drag free and orbit maintenance mission respectively.The technical project of ion propulsion is valuable for application reference of satellites in super low Earth orbit. 
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    Design method of multi-level regional reconnaissance elastic constellation
    WANG Hao, ZHANG Zhanyue, ZHANG Haitao, JIANG Ping
    Chinese Space Science and Technology    2021, 41 (4): 85-94.   DOI: 10.16708/j.cnki.1000-758X.2021.0054
    Abstract256)      PDF(pc) (4923KB)(130)      
    A design method of multi-level regional reconnaissance elastic constellations was proposed. The constellation design process was divided into three sub-constellation design steps according to region information until the whole constellation met the design requirements for all regional performance. Taking regions divided into 3 levels as an example, the constellation design requirements, design indicators and design steps were analyzed firstly. Then the relationship between the minimum resolution of the ground and orbital altitude was derived and the orbital altitude of different subconstellations was determined. Finally, the optimization models of basic constellation, subconstellation 1 and subconstellation 2 were constructed by considering orbital inclination, multisatellite launch and ascending nodal drift synchronization. The design case shows that the constellation designed with this method can meet the design requirements of regional coverage classification and elastic classification, which proves the effectiveness of the method. Compared with the design method of Walker constellation, the number of satellites required for multi-grade regional reconnaissance elastic constellation under the same design requirements is far lower than that of Walker constellation, which further proves the superiority of the proposed design method.
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    Recent research advances of passive intermodulation suppression methods for aerospace microwave components
    WANG Xiaoli, CHEN Xiang, LI Jun, CUI Wanzhao
    Chinese Space Science and Technology    2021, 41 (2): 1-9.   DOI: 10.16708/j.cnki.1000-758X.2021.0016
    Abstract240)      PDF(pc) (2921KB)(138)      
    Passive intermodulation (PIM) is widespread in high power microwave passive components and systems, which may cause serious interference in satellite and terrestrial communication systems. The PIM suppression technology is a key research issue in both theory study and engineering applications, and is important to solving various PIM problems. On the basis of explaining the generation mechanism of PIM, the existing PIM suppression methods and research status at home and abroad are systematically and comprehensively summarized from the aspects of process, structure, electrical design and signal processing, and the advantages and disadvantages of various suppression methods are discussed. On this basis, the subsequent development trends are analyzed. Based on traditional process structure optimization design, integrated design based on advanced manufacturing technology, contactless passive intermodulation suppression and digital signal processing to achieve PIM suppression are the important future directions, which bring new ideas and methods for PIM research.
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    A reversible data hiding scheme for remote sensing images
    HUI Zheng, ZHOU Quan
    Chinese Space Science and Technology    2020, 40 (6): 106-114.   DOI: 10.16708/j.cnki.1000-758X.2020.0077
    Abstract237)      PDF(pc) (8513KB)(81)      
    Reversible data hiding (RDH) can be used for lossless transmission of remote sensing images′ important target region. Based on the study of existing RDH schemes, it was found that the capacity of single embedment was not sufficient and that the process of auxiliary information required additional lossless binary compression, which cannot meet the effectiveness and real-time requirement of remote sensing image process. The smoothness of non-overlapping subblocks in carrier image was detected with a given threshold. Then RDH was achieved by encoding the differences between the reference pixel and the rest pixels in a smooth block, along with bit substitution. Capacity of a single embedment of the proposed scheme can be more than 500000 bit for a 512×512 pixel gray-scale remote sensing image. Experimental results show that the proposed algorithm can achieve reversible data hiding with the efficient capacity of single embedment, and yet no additional lossless binary compression is required for auxiliary information processing.
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    Research status and prospect of chemical-electrospray dual-mode propulsion system
    WU Qinqin, LIU Xinyu, DENG Hanwen, KANG Xiaoming
    Chinese Space Science and Technology    2021, 41 (1): 1-12.  
    Abstract231)      PDF(pc) (2873KB)(228)      
    The traditional chemical propulsion and electric propulsion have different characteristics and application ranges. The chemical propulsion has a thrust range from ~mN to ~N. In comparison with the electric propulsion, it has the characteristics of high thrust and wide thrust range. The electric propulsion can obtain a maximum specific impulse of thousands of seconds and a minimum thrust of ~μN. However, there are limitations for those two modes, and some complex space missions are difficult to be completed independently by any of them. The dual-mode propulsion system includes both chemical mode and electric mode, and has the characteristics of high specific impulse and wide thrust range, which can improve the flexibility of the spacecraft mission. Monopropellant chemical propulsion paired with ionic liquid electrospray propulsion has received the most attention recently. The principle and characteristics of the monopropellant-electrospray dual-mode propulsion system are introduced. The research status of dual-mode propulsion is summarized, and the existing problems and challenges are analyzed.
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    Study on the thermal radiation influence of the sputtering target on the ion thruster
    GENG Hai, SUN Mingming, LUO Junhua, LIU Jiatao
    Chinese Space Science and Technology    2021, 41 (2): 10-18.   DOI: 10.16708/j.cnki.1000-758X.2021.0017
    Abstract222)      PDF(pc) (5614KB)(112)      
    In order to study the thermal radiation influence of the sputtering target on the ion thruster in vacuum facility, finite element analysis was adopted to simulate the plume distribution of the thruster in vacuum chamber. Having obtained the temperature variation of the sputtering target caused by the influence of plume on the target, variation of temperature and thermal deformation of the grids caused by the increase of the sputtering target temperature were analyzed. The results show that the thruster plume can be described by a directional molecular flow model, and there was almost no energy loss in the plume diffusion process. The gas pressure in most areas of the vacuum chamber was in the range of 2×10-3 Pa to 6×10-3 Pa when the thruster was working. Under the influence of the sputtering target, the central temperatures of the accelerator grid and the screen grid were 352℃ and 440℃, and the edge temperatures were 342℃ and 411℃, respectively. The reduction of the gap between the screen grid and the accelerator grid increased from 0.560mm (without the sputtering target) to 0.585mm. The experimental results show that the temperatures at the edges of the accelerator grid and the screen grid were 364℃ and 385℃ respectively, with an error of 6% compared with the test results. The temperature test value of the plume at the rear of the sputtering target was about 50℃ higher than that in the simulation results, and the error was due to the neglection of the energy deposition of plume particles in simulation.
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    Satellite reliability analysis based on dynamic fault tree
    WANG Xuyu, HU Min, ZHANG Xueyang, ZHAO Yulong, LI Jiuyang
    Chinese Space Science and Technology    2020, 40 (6): 56-67.   DOI: 10.16708/j.cnki.1000-758X.2020.0072
    Abstract214)      PDF(pc) (5748KB)(112)      
    Aiming at the reliability problem of satellite system, a method for satellite reliability analysis based on dynamic fault tree was proposed. The dynamic fault tree model of three subsystems of satellite power, attitude and orbit control and propulsion was established by combining Markov chain and binary decision diagram. On this basis, the random fault model of satellite was obtained, and the reliability model of satellite was established by taking the depletion fault into consideration. Monte Carlo simulation was used to evaluate and analyze the random fault model, and its performance was compared with Weibull distribution model. The simulation results show that this method can effectively analyze the random fault of satellite, has the advantages of high computational accuracy and high efficiency, and can simulate the dynamic behavior of random fault of satellite components more effectively.
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    An autonomous orbit determination algorithm of XPNAV-1 based on extended Kalman filtering
    DING Taowei, SHUAI Ping, HUANG Liangwei, ZHANG Xinyuan
    Chinese Space Science and Technology    2021, 41 (1): 13-21.   DOI: 10.16708/j.cnki.1000-758X.2021.0002
    Abstract208)      PDF(pc) (2056KB)(129)      
    The world′s first dedicated pulsar navigation test satellite, X-ray pulsar-based navigation-1(XPNAV-1), was successfully launched by China in November, 2016. The satellite is operating normally in orbit, and a large amount of observation data has been acquired. The measured data of a single pulsar was used to verify the effectiveness of the satellite orbit improvement and the pulsar navigation system through the geometric constraint method. However, the longterm orbit determination process using a single pulsar had divergence problems. Based on the XPNAV-1 satellite expansion test mission and the need for subsequent development of pulsar navigation, the observation data of multiple pulsars was used to study the autonomous orbit determination algorithm of satellites based on extended Kalman filter (EKF). Firstly, the orbital mechanics model and observation equations of the satellite were established; secondly, the EKF filter algorithm and the observability analysis method of the piecewise constant system (PWCS) were discussed; finally, through a comprehensive analysis of the XPNAV-1 satellite observation data, pulsar coverage of satellite orbits and observability of system status, the autonomous orbit determination algorithm experiment was carried out. The test results show that the filtering process of the autonomous orbit determination algorithm based on EKF converges, which verifies the rationality and effectiveness of the algorithm.
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    Preliminary analysis of unexpected electrical breakdown characteristics of LIPS-200 ion thruster
    ZHANG Xueer, ZHANG Tianping, LI Detian, MENG Wei
    Chinese Space Science and Technology    2021, 41 (4): 41-48.   DOI: 10.16708/j.cnki.1000-758X.2021.0049
    Abstract206)      PDF(pc) (3821KB)(209)      

    Abstract: Unexpected electrical breakdown of the ion thruster directly affects the reliability of its engineering application. Based on the relatively complete data of breakdown events in the ground life test, a preliminary study was conducted on the breakdown phenomenon of LIPS-200 ion thruster in its 12000h life test with analysis approaches including data comparison, Weibull statistics and causal inference. Quantitative results were obtained, such as the average breakdown rate, the time distribution of breakdown events, the Weibull distribution of classified breakdown intervals. Analysis shows that the average breakdown rate of LIPS-200 is much lower than that of NSTAR and other products mainly because of its lower electrical field between grids; the distribution of breakdown events has a noticeable dependence on cumulative operating time; the characteristic breakdown intervals and breakdown rate change caused by different factors and mechanisms can be obtained with 2-parameter Weibull distribution model.
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    Isothermal performance analysis of heat pipe on GEO longlife satellites
    LIU Bailin, LI Yifan, HU Guojie, WANG Lu
    Chinese Space Science and Technology    2020, 40 (6): 89-98.   DOI: 10.16708/j.cnki.1000-758X.2020.0075
    Abstract204)      PDF(pc) (8266KB)(53)      
    The heat pipe is an important heat transfer element in thermal control design, which is used in a large number of GEO long-life satellites. On-orbit isothermal heat transfer performance of the heat pipe is a key factor affecting the safe and reliable operation of satellites. Aiming at studying the heat pipe of GEO longlife satellites that have long-term stable operation on orbit in China, the mathematical statistics method was used to analyze the law of the onorbit isothermal performance of the heat pipe with time, based on the temperature telemetry date on orbit. Results show that the heat pipe of GEO long-life satellites has good isothermal stability on orbit. The isothermal performance is greatly affected by the temperature level of the heat pipe. And it shows seasonal changes during the annual cycle and a downward trend in performance degradation over the entire life cycle with the flight time. The isothermal performance of the heat pipe at the end of its life is better than 1.6℃. In this paper, the isothermal improvement analysis and application suggestions are made from the aspects of heat pipe design, heat load size and distribution and its using environment.
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    Reconstruction method of regional reconnaissance elastic constellation based on improved MOPSO#br#
    WANG Hao, ZHANG Zhanyue, ZHANG Haitao, JIANG Ping
    Chinese Space Science and Technology    2021, 41 (2): 86-95.   DOI: 10.16708/j.cnki.1000-758X.2021.0026
    Abstract201)      PDF(pc) (3963KB)(94)      
    A reconstruction method based on an improved multi-objective particle swarm optimization algorithm was proposed. This method reconstructed damaged constellations by combining multi-satellite launch and on-orbit satellite phase maneuver. Firstly, reconstruction indexes were selected, including coverage, reconstruction cost, reconstruction time and elasticity. Secondly, the multi-satellite launching process and on-orbit satellite phase maneuvering were analyzed, and a uniform phase strategy was adopted for remaining normal satellites in damaged constellations. In order to restore original constellation performance, considering the maximum revisit time, elasticity, reconstruction cost and time, optimization models for reconstruction time and reconstruction cost were established. Finally, a MOPSO algorithm was improved, and a population update strategy based on learning mechanism was proposed. Discrete variables were transformed into continuous variables through variable transformation, which solved mixed variable optimization problems in reconstruction optimization models. Simulation for a damaged constellation shows that the time-optimal reconstruction scheme is launching 6 new satellites combined with the uniform phase of on-orbit satellites, and the cost-optimal reconstruction scheme is launching 4 new satellites combined with the uniform phase of on-orbit satellites. The case shows that the proposed reconstruction method is effective and can provide a reference for construction of reconnaissance constellations.
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    Overall technology analysis and efficiency simulation of the deep space impactor
    MA Xin, ZHOU Qi, LI Mingtao, ZHANG Huisuo
    Chinese Space Science and Technology    2021, 41 (1): 120-130.   DOI: 10.16708/j.cnki.1000-758X.2021.0015
    Abstract199)      PDF(pc) (4481KB)(100)      
    In order to impact the near-Earth asteroid 2016HO3 for scientific exploration, the "deep space impacting mission" and the present state of the deep space impactor were presented, the Hayabusa-2 deep space impacting mission was reviewed in detail, the scientific objectives of the deep space impactor with regard to China′s plan for future deep space missions to near-Earth asteroids were given. Through the deep investigation and analysis of the Hayabusa-2 impactor, the whole technology system of the deep space impactor which is based on explosively-formed projectile was obtained; the detailed technical analysis and technical connotation of the explosively-formed projectile, the safe and reliable explosion, the impactor separation, the impacting simulation and some other aspects were given systematically. The preliminary design of the deep space impactor for the near-Earth asteroid 2016HO3 was obtained. Through the impacting simulation, the results show that the diameters of impact craters vary from 32cm to 47cm with different impacting speed of 0.2cm/μs to 0.4cm/μs. The high resolution variation pattern of the diameter and depth of impact crater with different projectile thicknesses, impacting velocities, and projectile diameters were provided. This paper can provide technology support for the overall optimization of the deep space impactor.
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    An improved adaptive genetic algorithm for multi-satellite area observation scheduling
    FAN Yu, LIU Yingying, ZHOU Jun
    Chinese Space Science and Technology    2021, 41 (1): 38-47.   DOI: 10.16708/j.cnki.1000-758X.2021.0005
    Abstract193)      PDF(pc) (2370KB)(155)      
    Aiming at the shortcomings of the traditional optimization algorithm in solving the multi-satellite regional scheduling problem such as slow convergence speed and being prone to fall into the local optimal solution, an improved adaptive genetic algorithm was proposed. The algorithm uses Monte Carlo method combined with Hamming distance to give a better initial population. According to the average Hamming distance of the population, the execution sequence of crossover and mutation operations are determined. The Sigmoid function and Gaussian function are combined to design the adaptive nonlinear crossover rate and mutation rate based on the individual fitness of the population. The dual elite retention strategy and tournament strategy are combined to ensure the inheritance of the optimal individual. Dual shutdown condition is used to improve the search efficiency of the algorithm. Finally, experiment shows that the method can significantly improve the global search ability, accelerate the convergence speed of the algorithm, and effectively improve the observation efficiency of satellites.
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