25 April 2023, Volume 43 Issue 2 Previous Issue   
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Application and development of high-precision Hall electric propulsion technology
LIU Qi, MAO Wei, HU Peng, WEI Yanming, HU Yanlin, LI Yong, BIAN Bingxiu, LIU Xuhui
2023, 43 (2):  1-15.  doi: 10.16708/j.cnki.1000-758X.2023.0016
Abstract ( 42 )   PDF (8062KB) ( 70 )  
Under the application background of modern global communication and navigation,the abilities of precise orbit prediction and real-time orbit control of satellite platforms request better performances such as thrust accuracy and resolution ratio,so it is significant to construct high-precision electric propulsion system.According to the survey of the space application demand and the research status of electric propulsion technology,it is demonstrated that the output accuracy of thrust under current technology can not satisfy requirements of missions such as the high-precision continuous navigation,the real-time drag compensation of super low orbit satellites and imaging during the movement of high-resolution remote sensing satellites.Taking the Hall effect propulsion system as the research object and focusing on the technical difficulties of high-precision electric propulsion system,the research status at home and abroad was depicted,the development trends and the research routes of the key techniques were analyzed and discussed from the aspects of electric thruster technology,mass flow control technology,power supply and control technology as well as testing technology.The future focal directions of research and development were suggested for high-precision electric propulsion technology.
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Research progress and prospect of spacecraft reconfiguration technology
PENG Qibo, WU Xinfeng, WANG Beichao, LI Shuang
2023, 43 (2):  16-31.  doi: 10.16708/j.cnki.1000-758X.2023.0017
Abstract ( 104 )   PDF (6523KB) ( 91 )  
 Spacecraft reconfiguration technology is the key technology that must be broken through for the in-orbit service of spacecraft and other major space missions,having a profound effect on the design,research and development of new spacecraft systems.Firstly,the connotation and classification of the spacecraft reconfiguration were presented.Then,the domestic and overseas research status of the technology was systematically concluded and discussed based on main structure reconfiguration and other typical technologies.Next,the system of the spacecraft reconfiguration technology was proposed based on the methods such as standardized modular design,and then application prospects were summarized in the aspects such as supporting fault elimination of spacecraft.Finally,overall research progress of the reconfiguration technology was concluded,and future development was also expected.
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Forthcoming development trend of spaceborne SAR technology for earth environment monitoring
DENG Yunkai, ZHANG Heng, FAN Huaitao, YU Weidong, WANG Yu, TANG Xinming, GE Daqing, XU Feng, LIU Guoxiang
2023, 43 (2):  32-46.  doi: 10.16708/j.cnki.1000-758X.2023.0018
Abstract ( 23 )   PDF (20989KB) ( 35 )  
Focusing on the problems in the microwave remote sensing earth observation in terms of information dimension,inversion accuracy,observation efficiency and system architecture,several future spaceborne SAR technologies for comprehensive environmental monitoring were discussed based on the research achievements of the national key research and development program which was named as “Earth Environment Monitoring with Advanced Spaceborne Synthetic Aperture Radar”.In terms of ultra-large-width SAR imaging,a design scheme of segmented gradual variable pulse repetition frequency(PRF)sequence and a low-oversampling variable PRF data processing algorithm based on optimal linear unbiased estimation were proposed to realize large-scale wide-area spaceborne SAR imaging across blind areas.In terms of high-sensitivity SAR imaging,an intermediate-frequency digital beamforming(DBF)efficient on-board real-time processing architecture and a rapid generation algorithm for weighting factors were proposed,and the 16-channel airborne data were used to verify that the image signal-to-noise ratio was increased by about 11.2dB.In terms of multi-polarimetric SAR imaging,a compact polarization decomposition algorithm and a hybrid full-polarization azimuth ambiguity suppression method were proposed respectively,which were verified in the P/L band airborne flight test.In terms of high-precision interferometric SAR technology,a tomographic SAR processing method based on an improved phase compensation scheme was proposed,and the P-band full-polarization tomographic SAR data was used to verify that the forest height retrieval accuracy was better than 0.9meters.In terms of comprehensive environmental monitoring constellation architecture design,for wide-area surface elevation,surface deformation,wave spectrum energy,ocean current velocity,and biomass applications,a high-resolution wide-range SAR satellite solution with a quality factor of 100 was  completed,and the performance was greatly improved compared with in-orbit SAR satellites.
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Probe diagnosis of plume of micro-cathode arc thruster
WANG Shuai, LIU Xiangyang, ZHAO Zijing, GUO Haoran, GENG Jinyue, SHEN Yan, WANG Ningfei
2023, 43 (2):  47-54.  doi: 10.16708/j.cnki.1000-758X.2023.0019
Abstract ( 21 )   PDF (4763KB) ( 20 )  
Owing to the characteristics of low power and simple structure,microcathode arc thruster(μCAT)meets the mission requirements of micro-nano satellites,and thus has a good development prospect.The diagnosis of μCAT plume can reveal the acceleration mechanism of the thruster,which is of great significance for improving the performance of μCAT.The electron temperature,electron density and ion velocity at different positions of μCAT plume were obtained by using Langmuir threeprobe.The effects of external magnetic field,charging time and cathode material on plasma characteristics and ion velocity were investigated.The results show that the plasma generated at the initial stage of μCAT discharge has the characteristics of higher electron temperature and density.As the plume moves downstream,electron temperature and electron density decrease,and ion velocity increases.With the stronger external magnetic field,electron temperature and ion velocity increase,and electron density decreases.The electron density of the central axis of thruster is improved effectively when the external magnetic field is shifted to the downstream of thruster.As the charging time of μCAT is longer,the electron temperature,electron density and ion velocity increase.Compared with CuW and AgW cathodes,the electron temperature of Ti cathode plume is higher and electron density is lower.
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High power high efficiency solid state power amplifier used in space
YANG Fei, YIN Kang, ZHAO Hengfei, ZHAO Ying, LIU Jiangtao, YANG Shuli
2023, 43 (2):  55-62.  doi: 10.16708/j.cnki.1000-758X.2023.0020
Abstract ( 11 )   PDF (8851KB) ( 20 )  
 In response to the demands for microwave high power amplifier in satellite systems,an L-band 200W high-efficiency solid-state amplifier(SSPA)was developed and its design methods and key technologies were discussed.a highly integrated and miniaturized radio frequency unit(RFU)was realized with SSPA by using LTCC(low temperature co-fired ceramic)substrate.Based on the third-generation semiconductor devices,the power and efficiency of the RFU were improved by applying waveform shaping and linear compensation techniques.A high efficiency and high power secondary power supply was developed by using phase-shift-full-bridge(PSFB)topology.From 1.45GHz to 1.55GHz,the SSPA delivers more than 200W of output power with an associated 3rd order intermodulation product(IM3)and power added efficiency(PAE)better than 18dBc and 60% respectively.The gain can be adjusted within 30dB,whereas the phase can be adjusted within 360° range with a minimal step of 5.6°.The experimental results show that the SSPA is the most advanced with the highest power and efficiency in China.
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Mechanical model for lunar surface sampling based on modular theory
LYU Jiahang, LI Qian, HU Dingkun, LUO Haotian, ZOU Xinyue
2023, 43 (2):  63-72.  doi: 10.16708/j.cnki.1000-758X.2023.0021
Abstract ( 11 )   PDF (5989KB) ( 9 )  
 Not limited by the working space,there are various designs of lunar surface sampling devices,which brings great difficulty to establishing analysis model.In order to avoid duplicate modeling during the analysis of different structural tools,a modular mechanical model of lunar surface sampling was proposed.In this model,the complex sampling machine was divided into several basic surface units.The force of the surface unit in the sampling process was analyzed on the basis of Rankine′s earth pressure theory,the maximum shear strength theory and the ultimate bearing capacity theory of foundation.And the mechanical model of the complex machine was obtained by combining the forces of each surface unit.The theoretical model was verified by penetration tests with different machine forms and penetration angles based on lunar soil simulant.The error rate of the theoretical model was reduced to 8.2% by introducing the effect correction formula of the lunar soil density along the depth.The results show that the mechanical model and modular theory are feasible,which provides a reference for the design and development of the lunar surface sampling tool in the future.
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Multi-satellite task offloading method based on distributed deep learning
ZHOU Jinwen, LIU Naijin, CHEN Qingxia
2023, 43 (2):  73-80.  doi: 10.16708/j.cnki.1000-758X.2023.0022
Abstract ( 30 )   PDF (3932KB) ( 35 )  
In edge computing enhanced LEO satellite networks,collaboratively processing ground tasks by satellite clusters could effectively shorten the user response delay.The optimization of joint offloading decision and resource allocation of satellite clusters was studied,and was described as a mixed integer programming problem.A satellite edge computing enhanced deep learning-based offloading algorithm(DLOA)was adopted.The algorithm used multiple parallel DNN networks to generate offloading decisions and adopted experience replay to store the newly generated decisions.Particularly,the convergence rate of heterogeneous DNN with different hidden layer structure is 18% higher than that of homogeneous DNN with same hidden layer structure,and the ratio of convergent value to optimal value is basically 1,which can be considered to have converged to the optimal.In addition,the influence of the number of DNN on the proposed algorithm was discussed,and the simulation results show that the near-optimal effect can be obtained by using a small number of DNN.By studying the task completion rate of different algorithms under different task scales,the results show that DLOA algorithm can significantly improve the completion rate by using heterogeneous DNNs and optimized resource allocation schemes,which is twice as high as the single satellite scheme,and 20% higher than the binary particle swarm algorithm.
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Structure preserving method of isomerism multiple satellites formation under impulsive maneuver
YANG Shengqing, CHEN Junli, ZHONG Chao, LIU Yanyang, WANG Wenyan
2023, 43 (2):  81-92.  doi: 10.16708/j.cnki.1000-758X.2023.0023
Abstract ( 14 )   PDF (7401KB) ( 32 )  
 In near earth orbit,the initial state of two satellites formation configuration parameters is usually designed to achieve a controlled long-term stable relative motion.Focusing on the coupling relative motion caused by multiple satellites formation,an analysis method of relative motion was proposed on the basis of the Hill coordinates and trigonometric function formulas.Based on the definition of sensing baseline of synthetic aperture radar (SAR) load,combining with the relative motion character of formation configuration parameters,a design method of configuration parameter was put forward to find the maximum effective baselines combination.The long term effect of J2 term and air drag perturbation was analyzed,based on which the relative motion of isomerism multiple satellites formation was studied and a leader-follower form of bias control was proposed under impulse maneuver to preserve the designed formation configuration.The control method was validated in a four satellites formation with isomerism area-mass ratios.
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Satellite fault detection method based on time-series modeling
YANG Kaifei, HAN Xiaodong, LYU Yuancao, XU Nan, GONG Jianglei, LI Xiang
2023, 43 (2):  93-102.  doi: 10.16708/j.cnki.1000-758X.2023.0024
Abstract ( 22 )   PDF (4514KB) ( 22 )  
A kind of satellite fault detection method was introduced to handle the problems of relying on rule database,insufficient multi parameter fusion and unbalanced distribution of data samples in satellite fault detection.The semi-supervised model was constructed based on time-series characteristics of satellite data and was proposed to achieve effective excavation of satellite data rules and data driven fault detection.Considering the temporal correlation between satellite data,this kind of fault detection method was proposed based on long short-term memory network.Also,a sliding window mechanism was involved for better predicting and detecting efficiency.Considering the correlation between multiple parameters as another dimension,temporal convolutional network(TCN) and auto-encoder network were used to excavate the correlation between historical data and different parameters at the same time.Experimental results show that the proposed model is superior to traditional fault detection models such as BP neural network in key indicators.
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Research of UHF band relay communication key techniques for Mars exploration
ZHAI Shenghua, TIAN Jia, DONG Chao, LI Xiongfei, HUI Tengfei
2023, 43 (2):  103-116.  doi: 10.16708/j.cnki.1000-758X.2023.0025
Abstract ( 18 )   PDF (7638KB) ( 9 )  
Mars is the next milestone in our exploration of solar system.Due to the very long distance between the Earth and Mars(the longest distance is about 400 million kilometers,and the light travel time is about 22 minutes),in order to maximize the efficient communication between the Mars rover and the Earth,the inter vehicle relay communication technology between the Mars rover and the Mars Orbiter is particularly important.Aiming at overcoming the difficulties of low signal-to-noise ratio,rapid change of signal parameters,high requirements for full autonomy and extremely strict weight and power constraints of inter device communication in large elliptical orbit,a UHF band relay communication technique was proposed,mainly including ultra-high sensitivity and high dynamic adaptive signal demodulation,high precise Doppler measurement,the CCSDS Proximity-1 multiple dimensional integration and the highly integration and RX/TX isolation engineering design of transceiver product,achieving the acquisition sensitivity better than -141dBm,demodulation sensitivity(1kbit/s)better than -134dBm,frequency dynamic range better than ±26kHz,Doppler measurement precision better than 10mHz,RX/TX isolation greater than 180dB,fully autonomous,high reliability and high throughput communication in the visible arc section and system/product extreme optimization.The relevant performance indexes are better than the "Electra" in the American series of Mars probes.After the actual onorbit tests of the “Zhurong” Mars rover,the “Tianwen-1” Mars orbiter and the ESA “Mars Express” orbiter,the test data met the expectations and made a key contribution to the success of China′s first Mars exploration.
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Tracking method for code shift keying(CSK) modulated signal
YAN Tao, TIAN Ye, LI Tian, WANG Guoyong, WANG Ying, ZHOU Quan, BIAN Lang
2023, 43 (2):  117-127.  doi: 10.16708/j.cnki.1000-758X.2023.0026
Abstract ( 19 )   PDF (9105KB) ( 14 )  
 The code shift keying(CSK) modulated signal can support high data rate and meet the development needs for GNSS centimeter-level high-precision service.Thus,CSK modulated signal is attracting more and more attention.However,CSK modulated signal is usually only used in navigation message broadcast,but not ranging.To solve this problem,the tracking method for CSK modulated signal was studied,and two methods were proposed by tradeoff between performance and implementation complexity.Method one had high tracking accuracy with high implementation complexity,and method two reduced the implementation complexity at the cost of losing tracking accuracy.The tracking performance of the proposed methods was verified by theory and simulation.The results show that method one can provide the equivalent tracking performance to BPSK signal when C/N0 is higher than 40dB-Hz.Compared with method one,the required correlator resources by method two are reduced by 50%,but tracking performance of method two suffers 4dB degradation.The research results of this paper can provide a reference for the application of CSK modulated signal in GNSS high-precision signal design.
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Link-state-based adaptive interference cancellation for cabin in spacecraft
LIANG Wei, LI Jun, LI Jingling, CUI Tao, WEI Jiayuan, ZHANG Yi
2023, 43 (2):  128-134.  doi: 10.16708/j.cnki.1000-758X.2023.0027
Abstract ( 12 )   PDF (2474KB) ( 13 )  
 Focusing on the multi-interference problem of wireless optical ACO_OFDM system in spacecraft cabins,such as multi-path loss and burst interference,a method of link-state-based adaptive interference cancellation was proposed.The in-cabin link state for link-estimation was described.The method used an environment-adaptive RLS(recursive least squares)algorithm with variable forgetting factor,and adopted a differentiated interference elimination strategy for different link states,in order to improve the communication quality in the cabin.Simulation results show that the proposed method has better BER performance in the stationary state and better convergence performance when the link state changes,compared with the traditional algorithm which uses fixed forgetting factor,under the premise of avoiding the complexity of the algorithm.Therefore,the proposed algorithm can flexibly adapt to multiple transmission situations in the cabin.
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Multi-objective optimization design and precision analysis of truss antenna tetrahedron unit
WU Di, CHEN Jinbao, CHEN Chuanzhi, ZHAO Jiang, MA Xiaofei
2023, 43 (2):  135-143.  doi: 10.16708/j.cnki.1000-758X.2023.0028
Abstract ( 11 )   PDF (5190KB) ( 18 )  
 In order to reduce the influence of machining and assembly errors on the accuracy of antenna truss,and solve the optimization problems with random variables,the influence of assembly error of the normal distribution on the accuracy was considered.And the equilibrium state of truss antenna unit was solved by the principle of minimum potential energy.The influence of the change of the bar on the surface accuracy was analyzed by the Monte Carlo method,and the average accuracy under the random error was obtained.For improving the computational efficiency,an approximate model of the truss antenna tetrahedron unit with the bar length tolerance as the design variable was established,with the truss surface accuracy and overall processing cost as the objective function.Tolerance optimization design was carried out through the multiobjective optimization method,which obtained multigroup tolerance design scheme with the approximate model error less than 8%.In addition,the minimum average accuracy is 0.013mm,and the analysis result shows that the influence of the web rod is significantly greater than that of the bottom rod.
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Optimal reaction control for the flexible base redundant manipulator system
YIN Wang, WANG Xiang, WANG Wei, LIU Dongyu
2023, 43 (2):  144-154.  doi: 10.16708/j.cnki.1000-758X.2023.0029
Abstract ( 20 )   PDF (9209KB) ( 33 )  
 An optimal reaction control method was proposed for the trajectory tracking problem of the end effector of flexible base redundant manipulator systems.In the proposed algorithm,trace tracking is regarded as a high-priority task and the optimization of reaction control is implemented in the null-space of high-priority task.The self-motion of redundant manipulator can alter joint motion without affecting the motion of the end-effector,and can nullify the dominant modal force of vibrating system.Therefore,the vibration of base excited by rigid body motion is reduced greatly when the manipulator tracks specific trajectory.As a result,the stability of systems is improved.The effectiveness of the proposed algorithm is confirmed through numerical simulation with three-link manipulators and seven-DOF space manipulators with flexible base.
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Pretension design method of the cable network for asymmetric offset-feed mesh reflector antennas
FAN Yesen, NIE Rui, HE Baiyan, YANG Guigeng
2023, 43 (2):  155-164.  doi: 10.16708/j.cnki.1000-758X.2023.0030
Abstract ( 17 )   PDF (6165KB) ( 14 )  
A pretension design method of the cable network for asymmetric offset-feed mesh reflector antennas considering the influence of the truss flexible deformation on the equilibrium state of cable networks was presented.In this method,the mesh reflector antenna was divided into two parts:the internal cable network and the external truss.Through continuous iterations between the pretension of the cable network and the deformation of the external truss,a set of optimal pretension can be found based on satisfying the equilibrium state of the whole structure.Compared with the conventional pretension design method based on rigid truss assumption,this method can fully consider the compatible deformation between the external truss and the internal cable network to obtain a high surface accuracy reflector.This method can effectively avoid the tension readjustment to save manpower and material resources and applies to the pretension design for asymmetric offset-feed mesh reflector antenna.The case studies illustrate the necessity of considering the truss flexibility in the pretension design and demonstrate the correctness and effectiveness of the proposed method.
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Research on large area cloud forecasting method based on satellite cloud images
GU Yi, HAN Chao, LIU Jianxun, LIU Shenggang, XING Wei
2023, 43 (2):  165-173.  doi: 10.16708/j.cnki.1000-758X.2023.0031
Abstract ( 17 )   PDF (6791KB) ( 10 )  
Cloud cover is an important issue for Earth observation satellite imaging.When the proportion of clouds in the remote sensing image is too high,or the specific target is not visible,the remote sensing image will be invalid.Earth observation satellites can choose among multiple observation targets based on cloud forecast information.For the application of Earth observation satellite mission planning,a large-area short-term cloud forecasting method was proposed.First,the cloud motion vector was obtained by the Farneback optical flow method.Subsequently,the predicted cloud image can be obtained by extrapolating the cloud motion vector.Meanwhile,the Laplace operator was introduced to depict the characterization of the diffusion phenomenon in the process of cloud movement.Utilizing the real cloud image sequence data of the FY-2 satellite,the diffusion factor can be optimized through the backpropagation algorithm of the neural network to improve the effect of cloud forecasting.Through the analysis of forecasting results,the introduced Laplace operator method can improve the accuracy of cloud forecasting.The error of the 80% quantile of cloud coverage is about 11.7%.The cloud cover forecasting with this level of accuracy can be used to guide the mission planning of Earth observation satellites.
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Landsat 8 land surface temperature product validation and analysis
LI Shenglin, LIU Bo, ZHAO Ben, LI Dacheng, WANG Yuheng, GUO Fengyun
2023, 43 (2):  174-182.  doi: 10.16708/j.cnki.1000-758X.2023.0032
Abstract ( 22 )   PDF (9850KB) ( 16 )  
The thermal band of Landsat series satellites has a spatial resolution of 60-120m,which plays an important role in various environmental monitoring.With the release of land surface temperature (LST) product of Landsat series satellites worldwide,the validation work also begins.However,there is still a lack of validation for long time series.Taking the middle reaches of the Heihe River Basin as the study area,the Landsat 8 LST product with 31 clear and cloudless scene images from 2013 to 2016 were verified and analyzed by using the ground measured data observed by the three weather stations of Wetland Station (SD),Gobi Station (GB) and Daman Super Station (CJZ),and the Landsat 8 LST product was compared with the widely used single-channel algorithm (JMS) inversion results.The validation results show that the accuracy of both the Landsat 8 LST product and the JMS inversion results are high,and R2 at each site is better than 0.949.Based on the analysis of all sites,the accuracy of Landsat 8 LST product is slightly higher than the JMS.
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