2024 Vol. 44, No. 5

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Survey and Strategy
Trends and Strategic Planning Researches of Venus Exploration Abroad
HAN Lin, YANG Fan, FAN Weiwei, WANG Haiming
2024, 44(5): 753-762. doi: 10.11728/cjss2024.05.2024-yg08
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Europe, the United States, Russia and India have planned Venus exploration missions around 2030, and global Venus exploration is about to reach a new peak. This article systematically reviews the global Venus exploration missions that were launched or have been selected to implement in near future, conducts research on the US Venus exploration roadmap, analyzes the scientific goals, mission platforms, key technologies of Venus exploration, and reveals the characteristics of future Venus exploration missions and progress of long-term scientific and technological strategic planning abroad. By comprehensively analyzing the international Venus exploration trends, it is proposed that China should seize the opportunity to initiate Venus exploration as soon as possible, while strengthening support for scientific goals planning and long-term strategic research, hoping to provide reference for China’s Venus mission research and planning.
Space Physics
Deep Learning Prediction Method for f0F2 Parameters Based on the Ionospheric Parameter Similarity Features
ZHENG Dandan, CHEN Liang, WANG Junjiang, LIU Wen
2024, 44(5): 763-771. doi: 10.11728/cjss2024.05.2023-0110
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The ionosphere is an important component of the solar terrestrial space environment, and the critical frequency f0F2 parameter is one of the most important and complex ionospheric parameters. The changes in f0F2 parameters will have a certain degree of impact on communication, navigation, radar and other technologies, so predicting f0F2 parameters has important research significance and application value. This article proposes a deep learning prediction method that integrates the characteristics of f0F2 parameter changes. A model combining bidirectional long short-term memory neural network BiLSTM network and ionospheric parameter similarity features is used to predict the ionospheric critical frequency f0F2 parameter 24 hours in advance. The results show that the average relative error of BiLSTM combined with ionospheric parameter similarity model in predicting f0F2 parameters is about 8%～10%. Compared with the Long Short-Term Memory (LSTM) model, the average relative error has decreased by about 6% to 7%, while compared with the BiLSTM model, the average relative error has decreased by about 4% to 5%. The prediction results of the f0F2 parameter for different latitude detection stations show that as the latitude decreases, the difficulty of predicting the f0F2 parameter increases, the prediction errors of the three models increase, and the prediction accuracy decreases. The analysis of the prediction results of f0F2 parameters during geomagnetic storms shows that the predictive performance of the three models will be affected to varying degrees during the occurrence of geomagnetic storms, and the prediction error will increase. Compared to the calm period, the average relative error of the three models has increased by about 1% to 4%. During geomagnetic storms, compared with LSTM and BiLSTM models, BiLSTM combined with ionospheric parameter similarity feature models has better predictive performance for f0F2 parameters and better predictive performance. This method can also be applied to the prediction research of other ionospheric parameters such as Total Electron Content (TEC), hmF2, etc., and has a very broad application prospect.
Ionospheric TEC Prediction Based on QPSO-LSTM Model
GUO Wentao, SUN Xiyan, JI Yuanfa, JIA Qianzi
2024, 44(5): 772-781. doi: 10.11728/cjss2024.05.2023-0143
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For the ionospheric TEC short-term prediction of a single LSTM model, there are difficulties in parameter adjustment and performance Optimization, resulting in low prediction accuracy. Quantum Particle Swarm Optimization (QPSO) and LSTM model are combined. The quantum particle swarm optimization algorithm was used to determine the optimal solution, optimize the parameter configuration of the LSTM model, and use the model to predict the ionospheric TEC of low, middle and high latitudes 5 d in advance for three periods in 2014 and 2018, and analyze the prediction accuracy of the ionospheric TEC during the quiet period and disturbance period of geomagnetic activity. The experimental results show that when the LSTM model optimized by QPSO is used to predict TEC for 5 consecutive days, compared with the single LSTM model, the root-mean-square error of the QPSO-LSTM model is reduced by 0.34 TECU at most in low solar activity years, and the relative accuracy is increased by 2.68% at most in high solar activity years. The RMS error decreases by up to 0.68 TECU at low latitudes, while the relative accuracy increases by up to 2.36% at high latitudes. From different analysis angles, it is found that the prediction accuracy of QPSO-LSTM model is better than that of single LSTM model.
Observation of a Strong Ionospheric Storm Based on Electron Density Inversion of Yinchuan Vertical Ionosonde
HAN Sijia, LIANG Zhenzhen, GUO Wei, WANG Caiyun, FANG Qingyu, LI Lingling
2024, 44(5): 782-793. doi: 10.11728/cjss2024.05.2023-0148
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This study is based on the echo data from the Yinchuan vertical ionosonde. The ionosonde supports scanning in the frequency range from 1 to 30 MHz, with a distance resolution of 1.5 km and a reception window ranging from 67.5 km to 560.1 km. It utilizes pulse compression technology and encodes the transmission signal using Bernoulli mapping sequences, successfully resolving the issue of echo signal mixture with strong clutter interference in practical detection, thus obtaining Ionograms of high quality. In order to extract key information of ionosphere from the ionograms, the signal processing problem is transformed into a semantic segmentation task in computer vision, constructing an original ionograms dataset, and undergoing preprocessing such as discretization and manual annotation. By training a cGAN neural network to analyze the characteristic parameters of each layer’s traces in the ionograms, the goal of segmenting different traces is achieved. The network is suitable for processing various types of ionograms under calm conditions, with an accuracy rate of over 95%, effectively saving time in manual parameter measurement and improving processing efficiency. An improved bottom inversion model of the International Reference Ionosphere and the NeQuick top model is used to invert the electron density profile above the ionosonde, while the top calculation results are corrected according to the actual measurement data from “CSES-1”. By comparing the total electron content calculated with the data results publicly available from CDDIS, the accuracy of the ionosonde data is verified. On this basis, combined with the geomagnetic data acquired by the Gaoshaowo magnetometer, the ionosonde successfully observed the entire process of ionospheric anomalies during the geomagnetic storm on 23–24 April, 2023, and provided the results of the total electron content changes, offering accurate and reliable observational data for exploring the electromagnetic environment changes in western China.
Comparative between Temperature Data Detected by ICON/MIGHTI and TIMED/SABER
MU Xiao, YAN Zhaoai, CHENG Xuan, CHEN Zhifang, YANG Junfeng, HU Xiong, PAN Weilin
2024, 44(5): 794-805. doi: 10.11728/cjss2024.05.2023-0094
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The ICON satellite provides new data for environmental characterization, modeling, and forecasting in near space. In this paper, the ICON/MIGHTI and TIMED/SABER temperature datasets were compared and analyzed in the range of 90～105 km, and the mean temperature deviation and root-mean-square error of both were calculated. The distribution of monthly mean temperature deviation with altitude and latitude in different months was also analyzed, which is useful for applying the MIGHTI and SABER temperature data in the model and forecast. The results showed that the MIGHTI and SABER vertical profile detections agreed. In the range of 12°S－42°N, the MIGHTI probe temperature is lower than that of SABER in the range of 90～93 km, with a maximum deviation of about 2.5 K, and higher in the range of 93～105 km, with a maximum absolute value of the deviation of about 10 K. The deviation was usually higher during the day than at night. The mean temperature deviation varied significantly with season and latitude and had the largest mean deviation range and the largest root-mean-square temperature error in summer.
Application of Deep Clustering Algorithm in Target Echo Classification of SuperDARN Radar
KONG Xing, LIU Erxiao, CHEN Fengju, QIAO Lei
2024, 44(5): 806-817. doi: 10.11728/cjss2024.05.2023-0136
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SuperDARN radar target echoes usually contain echoes of various types of scattering, such as ionospheric irregularities, ground/sea scatter echoes, polar mesosphere summer echoes and meteor trail echoes. The ionospheric echoes collected by SuperDARN radar are used to map the ionospheric convection to study the large-scale dynamics of the magnetosphere-ionospheric system, which is of great significance for space weather observation and exploration. In general, the scattered ionospheric echoes received by SuperDARN are often mixed with the scattered echoes from the ground or the sea, resulting in inaccurate ionospheric convection maps. Therefore, cluster analysis of SuperDARN target echoes is of great significance. Traditionally, ground/sea scattering is determined by the lower threshold of the combination of velocity and spectral width, but the scope of use of this method is limited, and there is ambiguity for the echoes in the mid-latitude region. In order to avoid the influence of latitude conditions and reduce the omission of useful information in the data, multiple data features of the radar target echo are collected as much as possible, such as line-of-sight Doppler velocity, the spectral width, backscatter power and the elevation angle of arrival. In this paper, the graph embedding deep clustering algorithm based on autoencoder network is applied to SuperDARN target echo data for the first time, and SuperDARN echo data is effectively classified. In addition, two different types of machine learning clustering algorithms are introduced to compare with this model. The deep clustering model, traditional classification algorithm and machine learning clustering algorithm are applied to the same echo data set, and the clustering results of different clustering algorithms are compared. The application of different clustering models on sample data sets and the evaluation of clustering indexes show that the deep clustering algorithm can capture the deep structural features of the echo data, effectively compress and reduce the dimensionality of the high-dimensional data set, make full use of the useful information in the data set, and improve the precision of the target echo data clustering of SuperDARN radar.
Space Earth Science
Advances in the Study of the Methods for Detecting the Earth Magnetic Field from Passive Microwave Remote Sensing
WANG Kexin, WANG Zhenzhan
2024, 44(5): 818-831. doi: 10.11728/cjss2024.05.2023-0117
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The geomagnetic field is a crucial physical field of the Earth, playing an essential role in various domains such as earth and space physics research, applied research in geology, and national strategic security. To facilitate profound scientific and applied investigations in geomagnetics and related fields, it is important to develop magnetic field measurement methods that are highly convenient, cost-effective, cover a wide spatial range with exceptional precision, and provide multi-dimensional geomagnetic data. In order to overcome the limitations of on-site magnetic field measurement methods based on high-precision magnetometers regarding efficiency and detection range, remote sensing detection has emerged as a promising new area for magnetic field detection. This paper comprehensively analyzes the fundamental principles, research progressions, and application status of microwave radiometer remote sensing technology for studying the geomagnetic field. Based on this analysis, discusses the requirements and technical challenges faced by this method along with future development trends aimed at enhancing its detection capabilities. Furthermore, it proposes new prospects for future research in magnetic field remote sensing detection including planetary magnetic field remote sensing.
Amplitude Calibration Method for Synthetic Aperture Radiometer Based on Cold-sky Observation Unit
TONG Xing, NIU Lijie, HAN Donghao, LIU Hao
2024, 44(5): 832-845. doi: 10.11728/cjss2024.05.2023-0131
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Microwave radiometers obtain the accurate brightness temperature of the target scene through calibration, which is a necessary means for quantitative data application. The synthetic aperture microwave radiometer consists of multiple radiometer units, and the calibration requirement extends from a single receiver to all units. Noise injection is a calibration method for fixed antenna beam radiometers, including synthetic aperture microwave radiometers. However, the noise diode used as the calibration reference encounters issues such as short-term fluctuation caused by temperature and long-term drift resulting from the aging of the device, leading to the deterioration of the system's calibration accuracy. To address the aforementioned problems, this paper proposes a method of amplitude calibration for synthetic aperture radiometers based on a special cold-sky observation unit. By designing a dedicated cold-sky observation radiometer channel, the common noise source of the synthetic aperture radiometer is calibrated in real-time, reducing the influence of noise temperature uncertainty on the amplitude calibration of all observation channels in the synthetic aperture radiometer system. Based on the system scheme of the K-band one-dimensional synthetic aperture radiometer in the Microwave Imager Combined Active and Passive of China’s Ocean Salinity Detection Satellite, the radiometer system model and calibration model are established, and numerical simulations and prototype calibration experiments are carried out. Simulation and experimental results validate the effectiveness of the proposed method.
Microgravity and Space Life Science
Research on Interfacial Flow and Thermal Stratification of Cryogenic Liquid Nitrogen in Variable Gravity
ZHANG Min, LIU Qiusheng, TAO Yuequn, HE Naifeng
2024, 44(5): 846-862. doi: 10.11728/cjss2024.05.2023-0111
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In order to study the effects of residual gravitational acceleration g on the flow, phase distribution, temperature distribution, and pressure distribution of liquid nitrogen tank during self-pressurization, the self-pressurization process of liquid nitrogen tank under different g was numerically simulated by the Volume-of-Fluid (VOF) method. The results show that under the condition of large g, the fluid pressure in the tank increases gradually along the direction of residual gravity, and the temperature of the ullage in the tank increases with the continuous heat leakage of the tank wall, and the gas temperature near the wall is the highest, and the gas temperature near the liquid is the lowest, while the temperature in the liquid bulk zone of the tank changes little with time. With the decrease of g, the liquid in the tank is more likely to climb along the wall of the tank with better infiltration, and the temperature difference of the fluid in the tank is gradually reduced. In the case of small g, after the fluid flow in the tank is stable, the ullage will be wrapped in the middle of the tank, forming a spherical bubble. The difference of the fluid temperature in the tank gradually increases and then decreases with time. In zero gravity environment, the presence or absence of heat leakage (qw = 0.5 W⋅m–2) on the tank wall has no significant influence on the fluid movement and phase distribution in the tank, and within the initial time interval $\Delta t_{\mathrm{f}} $ (0 ≤ $\Delta t_{\mathrm{f}} $ ≤ 40 s), the influence of the presence or absence of qw on the temperature distribution of the fluid in the tank also is not significant except near the wall of the tank. Numerical simulation results are expected to provide references to further study the on-orbit pressure control technique of cryogenic liquid tanks and space cryogenic fluid management.
Numerical Simulation of Interfacial Oscillation Inside a Micro-pin-finned Structure
WANG Sulong, DU Wangfang, HE Falong, ZHAO Yanlin, YAO Jun, ZHAO Jianfu
2024, 44(5): 863-872. doi: 10.11728/cjss2024.05.2024-0030
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The oscillation and reconstruction of gas-liquid interface caused by sudden drop of gravity is of great significance to space fluid management. Taking into account of the important role of the tank wall’s wetting characteristics, this paper draws on the idea of designing the surface of the square column micro-structure in the field of heat transfer enhancement, and puts forward a passive anti-shaking idea of the space tank by using the damping effect of the square column micro-structure wall on the liquid oscillation. In addition, the gas-liquid interface oscillation characteristics in a special-shaped basic unit formed by a square column microstructure were numerically simulated by using the Volume of Fluid (VOF) method, and the variation of the free liquid surface characteristics with time was analyzed. In particular, the oscillation frequency, damping characteristics and other parameters closely related to the energy dissipation characteristics of the system were discussed, which provided the reference basis for space applications. The results show that the gas-liquid interface within the square-column microstructure produces a repositioning phenomenon accompanied by damped oscillations when gravity plummets from a strongly overloaded state. The initial liquid level height mainly affects the amplitude of the liquid surface oscillation. An initial liquid level lower than 30 μm leads to a bottoming out of the liquid surface during the oscillation process, which increases the damping ratio. In the absence of bottoming out, the higher the initial level is, the lower the amplitude of the oscillation is. The contact angle affects the amplitude and damping ratio of the oscillation process, and both the amplitude and damping ratio decrease gradually as the contact angle increases. In a wide gravity range, the magnitude of the final gravity level is between microgravity and 10 times normal gravity, the gas-liquid two-phase flow characteristics inside the square-column microstructures are similar, and the gravity effect is rather weak.
Space Radiation-induced Impacts on Gut Flora, Metabolites and Multisystem Diseases
WU Zhujun, ZHANG Xin, PANG Yudi, DENG Yulin, WANG Zhimin
2024, 44(5): 873-883. doi: 10.11728/cjss2024.05.2023-0126
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Maintaining the homeostasis of gut flora is of great significance to protecting human health. Gut flora plays a key role in regulating body functions, such as digestion, metabolism, immunity, and cognition. These physiological functions often depend on the diversity of gut flora, the stability of the bacterial flora structure, and the balance of the microecology. In the outer space, astronauts face many special environmental factors including the space radiation. Space radiation can cause imbalance of gut flora and changes in metabolites, damaging the intestinal barrier function, and further lead to pathological injury to multiple systems such as the intestine, cardiovascular, brain, and lungs. This paper reviews the characteristic changes in gut flora homeostasis and its metabolites under space flight or simulated space radiation, as well as the interaction between gut flora and intestinal damage and other multi-system diseases under radiation effects. It is expected to provide a reference for the further study of the pathological mechanisms upon space radiation and radiation protection measures.
Space Exploration Technology
Research Progress of Rankine Cycle System for Space Nuclear Power System
WANG Jiewei, LIU Kaixuan, YANG Yi, LÜ Zheng
2024, 44(5): 884-893. doi: 10.11728/cjss2024.05.2023-0141
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The space nuclear power Rankine cycle is a research hotspot in the field of space nuclear reactor power supply because of its high thermoelectric conversion efficiency, small waste heat radiation area and flexible power change. In this paper, based on the in-depth analysis of the development history of space nuclear power Rankine cycle at home and abroad and the research progress at home and abroad, the research progress of the workmass of space nuclear power Rankine cycle is sorted out, and the selection criteria and principles of workmass are summarized. In this paper, a detailed review of the design schemes of space nuclear energy Rankine cycle systems of different power levels is carried out, summarizing the reactor design, the selection of industrial materials for each circuit, the design of Rankine cycle power, the design of key components and other aspects of each system scheme, and it is found that the main research directions include the research on the characteristics of the industrial materials, the research on the key components of the Rankine cycle, the design of the reactor core, etc. The key technical issues to be further studied include research on new metal materials, high-performance key equipment design and ground integration program. The results of the analyses are intended to provide a certain reference for the design and research of the Rankine cycle for space nuclear energy in China in the future.
Topological Optimization of Spatial Indexing Mechanisms Based on Nonlinear Characteristics
LIU Hanwu, LI Changjun, JIN Xiaoping, ZHANG Hua
2024, 44(5): 894-902. doi: 10.11728/cjss2024.05.2023-0087
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For the lightweight design of the space station transfer mechanism with nonlinear characteristics, a structural/mechanism topology optimization method considering nonlinear characteristics was established, and the force-displacement curve was obtained by simulating the static test process. The equivalent stiffness of the nonlinear structure was extracted according to a specific principle, which could match the test results well. The topology optimization analysis and weight reduction design of the intermediate bracket of the space station transfer mechanism were carried out using the method of Solid Isotropic Material with Penalization (SIMP), and the structure was reduced by 24%, achieving the goal of lightweight design for the space station transfer mechanism. This shows the effectiveness of the analysis method. The topology optimization method established for the lightweight design of the space station transfer mechanism with local nonlinear characteristics provides a solution for the lightweight design of other nonlinear structure mechanisms, and also provides a reference for other nonlinear structure mechanisms. As the demand for advanced materials and structures with improved performance continues to grow, the topology optimization method established for the space station transfer mechanism will serve as a valuable tool for engineers working in various fields. For example, it can be applied to the development of lightweight automobiles, aircraft, and spacecraft, as well as to the design of renewable energy systems, robotics, and other advanced technologies. By incorporating the method into their design processes, engineers can create more innovative and efficient products that will help to drive progress and advancements in these industries. In conclusion, the topology optimization method developed for the lightweight design of the space station transfer mechanism with local nonlinear characteristics has demonstrated its effectiveness and versatility in addressing complex engineering design challenges. By providing a systematic approach to the design process that considers both structural and mechanical properties, this method has the potential to impact various industries and applications, contributing to the development of more advanced and sustainable structures and mechanisms for years to come.
Orbit Anomaly Detection Technology Based on Segmentation Optimization
CAO Jifeng, YANG Xiaohua, WANG Ronglan, YU Shengxian, LUO Bingxian
2024, 44(5): 917-927. doi: 10.11728/cjss2024.05.2023-0122
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In recent years, the large number of deployments of low-orbit giant constellation satellites have a significant impact on the operational safety of low-orbit satellites in orbit, and it is critical to detect orbital anomalies of constellation satellites in time. As a result, this study picks the Starlink satellite constellation as the research objects for detecting orbit anomaly and presents an improved orbit anomaly detection approach - segmentation optimization. Based on the concept of dynamic optimization, the approach improves the orbit anomaly detection method by using satellite orbit semi-major axis data as an analysis parameter, transforming it from threshold screening to optimization search. First, by assuming the segmentation points and randomly distributing them across the entire semi-major axis data series, the data in the time window are randomly segmented. Based on the variance of the segmented data, each segment's loss function is built. The iterative function are then designed using the loss function for optimization iterations. In order to determine the optimal segmentation method, the random segmentation is finally optimized with the goal of minimizing the sum of the total loss functions. This research finds that the anomaly detection effect is the best for the semi-major axis data by the differential processing after evaluating a range of data. The segmentation optimization approach has various sensitivities to different data after removing the noisy data. In conclusion, this work uses the TLE (Two-line element) data and the ephemeris data from the Starlink satellite for example verification, which was launched on 28 February 2023. The method's effectiveness in detecting orbital anomaly of constellation satellites is demonstrated, which are simple and efficient.
Design of Uncertain Attitude Control Method for Deep Space Probe Based on Fuzzy Control
DU Yu, JIN Shibo, YANG Donglai, HUANG Xingrong
2024, 44(5): 928-938. doi: 10.11728/cjss2024.05.2023-0128
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In space exploration missions, attitude control is the basis to ensure the completion of various tasks, especially in the take-off and landing stage plays a key role. Although the landing control technology of the spacecraft is becoming more and more mature, the attitude control of the extraterrestrial take-off stage is still less studied. In this paper, a fuzzy controller is designed for the launch of a deep space probe in the alien uncertain environment. Firstly, the detector model used in this paper is summarized, and the attitude description method and corresponding kinematic equation are given. Then, according to the fuzzy control principle, the fuzzy control rules which map the attitude Angle and angular velocity to the output torque are established. Finally, the fuzzy attitude Angle and angular velocity are taken as the input, and the corresponding fuzzy output is obtained according to the fuzzy rule, and the switch state output of the controller engine is obtained by deblurring, so as to realize the fast and effective control of the detector attitude. Then, numerical simulation was used to test the control effect of the controller and its robustness when there is a deviation between the initial attitude and the engine installation. Finally, physical simulation of the probe take-off process was carried out in ADAMS environment combined with Simulink module. According to the above analysis and simulation, the results show that compared with the control divergence caused by the classical PD control method when the actual model is different from the ideal model, the controller has stronger robustness under parameter uncertainty, and meets the demand for attitude control during the autonomous take-off of deep space probes. This study provides an effective fuzzy control scheme for extraterrestrial liftoff, which provides a theoretical and methodological basis for further research.
Design and Implementation of Space Manipulator Operating Subsystem
QIU Xin’an, MA Dongtao, TIAN Licheng, HU Yuqian, WU Zhihong, ZENG Zhenglin, WEI Zhiming, DUAN Fuwei, XIAO Qiang, MA Hongjiong, SHI Wei
2024, 44(5): 939-947. doi: 10.11728/cjss2024.05.2023-0081
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As an important platform for the construction and on-orbit operation of space station, the space manipulator operating subsystem is the first independently developed large-scale space robotic system for aerospace engineering applications in China. The space robot arm has 14 degrees of freedom under the combination of the two arms, with large motion inertia, high operating precision, and support for multi-mode work. In this paper, according to the characteristics of space manipulator on-orbit mission, a space manipulator operation subsystem is established, which is supporting long-term on-orbit and multi-mode operation. The operation subsystem is composed of manipulator console, virtual simulation platform and display, which can meet the requirements of multitasking. This paper provides a summarize overview of the architecture, working mode, and technical characteristics of the operation subsystem, and focuses on analyzing the system bus structure, multimodal human-computer interaction technology, and force perception rendering algorithms of the operation subsystem. According to the ground test and on-orbit work, the verification of space manipulator operation subsystem is obtained, which provides valuable experience and data for space manipulator operation mission. The results show that the space manipulator operating subsystem can better carry out on-orbit management of the space robotic arm, monitor the whole process of it, as well as ground and on-orbit remote control and manipulation; the application of force perception rendering technology can better support the fine manipulation of the space robotic arm end and joints; the virtual simulation platform can effectively simulate the on-orbit tasks of the space robotic arm and simulate the pre-task rehearsal and training of the support task. The space manipulator operating subsystem has accumulated experience and data to support space robotic arm mission implementation.
Method of Star Point Extraction for Daytime Infrared Star Image
YANG Yuan, GOU Wanxiang, LI Chonghui, TONG Shuai, ZHANG Chao, ZHANG Junzhang
2024, 44(5): 948-956. doi: 10.11728/cjss2024.05.2023-0123
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The daytime infrared star image has the characteristics of high background noise, low signal-to-noise ratio and weak target, so it is difficult to accurately extract the star centroid by using the traditional single frame extraction method. Because the stars are weak and small targets, they are extremely sensitive to noise, and the star imaging is mostly random and irregular, so the robustness of extracting the star centroid by single frame is poor. Although the traditional multi-frame superposition method can overcome the problem of poor robustness of star centroid extraction in single frame, for infrared star images with high background noise, the superposition star image cannot significantly improve the signal-to-noise ratio, and the success rate of star extraction is still low. Therefore, this paper proposes a method that uses background prediction method to determine the position of suspected stars, expands the boundary, and then uses the expanded boundary to extract the energy of single frame star image, and superimposes the extracted energy star image to form a high signal-to-noise ratio star image, and finally extracts the star centroid. Experiments show that the accuracy of star extraction is 99.5%, which is 84.2% and 37.9% higher than that of adaptive threshold segmentation method and multi-frame superposition method, respectively, and 14.5% higher than that of background prediction method. At the same time, the accuracy of this method is improved by 12.8%, 41.4% and 33.3%, respectively, compared with the adaptive threshold segmentation method, background prediction method and multi-frame superposition method, which has obvious advantages over the traditional method.
Remote Sensing Satellite Ground Station Antenna Occlusion Forecasting Model and its Application
FU Weilong, SHI Lu, WU Fengxia, DENG Shaohua, TIAN Miaomiao, MA Guangbin
2024, 44(5): 957-964. doi: 10.11728/cjss2024.05.2023-0134
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Based on the practical problems encountered in the operational operation of remote sensing satellite ground stations and operational experience, this paper aims to reduce the impact of obstructions around the antennas of ground stations on the space communication missions of polar orbit satellites such as low-orbit space science satellites and land observation satellites. With the goal of improving the effective communication duration and communication quality between the spacecraft and the ground, the ground station antenna is used as a benchmark for modeling and analyzing the obstructions in the surrounding environment. First establish the occlusion model spatial geometry relationship. The model is chosen to derive the solution for the “minimum elevation angle of the antenna without obstruction”. The solid occlusion model equations and large antenna Occlusion model equations are obtained through model analysis and derivation. Through the model validation, it shows that the model results and the actual situation of the occlusion basically match, and the accuracy of the model calculation results can reach 99.67%. Using the antenna occlusion forecast model as information support, the antenna occlusion forecast is encapsulated into a service, and the computation service of the antenna occlusion forecast and the corresponding mission planning strategy are invoked in the mission planning stage, so as to realize the engineering application of the antenna occlusion forecast model in the operation and management resource scheduling of a ground station. The results of trial operation and application statistics show that the optimization rate of operation management resource scheduling of a ground station has reached 56.07%.

Journal Introduction

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