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satellite anomaly detection based on reconstruction discrepancy theory utilizing a new dual-branch reconstruction model

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Science China Technological Sciences 2024年第10期67卷 3294-3307页

作者： ZHAO HaoTian QIU Shi LIU Ming CAO XiBin Research Center of satellite Technology School of AstronauticsHarbin Institute of Technology

To enhance the accuracy of deep learning methods based on reconstruction discrepancy in satellite anomaly detection tasks, this study proposes a dual-branch reconstruction model(DBRM) and designs a comprehensive satellite anomaly detection framework around this model. Firstly, we introduce the temporal-channel mixer(TC-Mixer) module, which mainly comprises a self-attention layer for capturing long-range temporal dependencies in telemetry data, and two types of feed-forward networks(FFN) for extracting complex patterns in the temporal and channel dimension of telemetry data. This design endows the TC-Mixer module with robust capabilities for extracting complicated dependencies in telemetry data. Secondly, with the TC-Mixer module as the main component, we designed the DBRM. This model utilizes a shared latent representation layer, allowing the regeneration branch and forecasting branch of the DBRM to share most of the feature extraction network architecture. This approach significantly enhances the model's regression accuracy while reducing computational complexity. Thirdly, using the DBRM as the core network model, we devised a comprehensive satellite anomaly detection framework. This includes an anomaly criterion that considers the reconstruction discrepancy of both the regeneration and forecasting branches, the peak-over-threshold(POT) method for anomaly thresholding, and the MIC-based feature engineering method, etc. Finally, we conducted comparative experiments with several SOTA anomaly detection algorithms on two public and one private satellite anomaly detection datasets. The experimental results validate the effectiveness and superiority of our proposed method.

关键词： anomaly detection reconstruction discrepancy dual-branch reconstruction model (DBRM) satellite telemetry data time series

Nonlinear characteristics of torsional stiffness of a coilable mast with triangular section

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Chinese Journal of Aeronautics 2024年第10期37卷 313-324页

作者： Yu LIU Liang SUN Hai HUANG Shenyan CHEN Weipeng LI Xurui ZHAO School of Astronautics Beihang UniversityBeijing 100191China institute of Remote Sensing satellite China Academy of Space TechnologyBeijing 100094China

With numerous applications coilable masts in high-precision astronomical observations,such as X-ray source observations,it is important to investigate mast *** date,there have been many studies on the bending stiffness of coilable masts,but few studies on their torsional stiffness,especially regarding the nonlinear characteristics of torsional stiffness of coilable masts under large torsional *** this paper,a nonlinear analysis method is presented to examine the torsional stiffness of coilable masts with triangular *** on the second-order bending buckling hypothesis of battens under large torsion deformation,the nonlinear relationship between torsional torque and torsional angle is obtained by analyzing torsional deformation and force of coilable *** method is used to analyze the torsional stiffness nonlinearity of a certain type of coilable mast which will be used in a practical application in the future and the results are verified by simulation and *** comparison results show that the error is within the acceptable range,which proves the effectiveness of the proposed method.

关键词： Coilable mast Torsion testing Torsional stiffness nonlinearity Torsional deformation Torsion simulation

The First Global Map of Atmospheric Ammonia(NH_(3)) as Observed by the HIRAS/FY-3D satellite

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Advances in Atmospheric Sciences 2024年第3期41卷 379-390页

作者： Minqiang ZHOU Zhili DENG Charles ROBERT Xingying ZHANG Lu ZHANG Yapeng WANG Chengli QI Pucai WANG Martine De MAZIÈRE institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China Royal Belgian institute for Space Aeronomy(BIRA-IASB) Brussels 1180Belgium National satellite meteorology Center China Meteorological AdministrationBeijing 100081China Department of Science&Technology and Climate Change China Meteorological AdministrationBeijing 100081China University of Chinese Academy of Sciences Beijing 100049China

Atmospheric ammonia(NH_(3)) is a chemically active trace gas that plays an important role in the atmospheric environment and climate change. satellite remote sensing is a powerful technique to monitor NH_(3) concentration based on the absorption lines of NH_(3) in the thermal infrared region. In this study, we establish a retrieval algorithm to derive the NH_(3)column from the Hyperspectral Infrared Atmospheric Sounder(HIRAS) onboard the Chinese Feng Yun(FY)-3D satellite and present the first atmospheric NH_(3) column global map observed by the HIRAS instrument. The HIRAS observations can well capture NH_(3) hotspots around the world, e.g., India, West Africa, and East China, where large NH_(3) emissions exist. The HIRAS NH_(3) columns are also compared to the space-based Infrared Atmospheric Sounding Interferometer(IASI)measurements, and we find that the two instruments observe a consistent NH_(3) global distribution, with correlation coefficient(R) values of 0.28–0.73. Finally, some remaining issues about the HIRAS NH_(3) retrieval are discussed.

关键词： ammonia HIRAS/FY-3D satellite thermal-infrared observation remote sensing optimal estimation method

A Recursive DRL-Based Resource Allocation Method for Multibeam satellite Communication Systems

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Chinese Journal of Electronics 2024年第5期33卷 1286-1295页

作者： Haowei MENG Ning XIN Hao QIN Di ZHAO State Key Laboratory of Integrated Services Networks Xidian University China Academy of Space Technology Institute of Telecommunication Satellite

Optimization-based radio resource management(RRM) has shown significant performance gains on high-throughput satellites(HTSs). However, as the number of allocable on-board resources increases, traditional RRM is difficult to apply in real satellite systems due to its intense computational complexity. Deep reinforcement learning(DRL) is a promising solution for the resource allocation problem due to its model-free advantages. Nevertheless, the action space faced by DRL increases exponentially with the increase of communication scale, which leads to an excessive exploration cost of the algorithm. In this paper, we propose a recursive frequency resource allocation algorithm based on long-short term memory(LSTM) and proximal policy optimization(PPO), called PPO-RA-LOOP,where RA means resource allocation and LOOP means the algorithm outputs actions in a recursive manner. Specifically, the PPO algorithm uses LSTM network to recursively generate sub-actions about frequency resource allocation for each beam, which significantly cuts down the action space. In addition, the LSTM-based recursive architecture allows PPO to better allocate the next frequency resource by using the generated sub-actions information as a prior knowledge, which reduces the complexity of the neural network. The simulation results show that PPO-RA-LOOP achieved higher spectral efficiency and system satisfaction compared with other frequency allocation algorithms.

关键词： High-throughput satellites Proximal policy optimization Deep reinforcement learning Long-short term memory High-throughput satellites Proximal policy optimization Deep reinforcement learning Long-short term memory OPTIMIZATION POWER

Limited Sea Surface Temperature Cooling Due to the Barrier Layer Promoting Super Typhoon Mangkhut(2018)

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Advances in Atmospheric Sciences 2024年第11期41卷 2156-2172页

作者： Huipeng WANG Jiagen LI Junqiang SONG Liang SUN Fu LIU Han ZHANG Kaijun REN Huizan WANG Chunming WANG Jinrong ZHANG Hongze LENG College of meteorology and Oceanography National University of Defense TechnologyChangsha 410073China School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230000China State Key Laboratory of satellite Ocean Environment Dynamics Second Institute of OceanographyMinistry of Natural ResourcesHangzhou 310012China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519082China

This study investigates the impact of the salinity barrier layer(BL)on the upper ocean response to Super Typhoon Mangkhut(2018)in the western North *** the passage of Mangkhut,a noticeable increase(~0.6 psu)in sea surface salinity and a weak decrease(<1℃)in sea surface temperature(SST)were observed on the right side of the typhoon ***-induced SST change can be divided into the three stages,corresponding to the variations in BL thickness and SST before,during,and after the passage of *** the pre-typhoon stage,SST slightly warmed due to the entrainment of BL warm water,which suppressed the cooling induced by surface heat fluxes and horizontal *** the forced stage,SST cooling was controlled by entrainment,and the preexisting BL reduced the total cooling by 0.89℃ d-1,thus significantly weakening the overall SST cooling induced by *** the relaxation stage,the SST cooling was primarily caused by the *** results indicate that a preexisting BL can limit typhoon-induced SST cooling by suppressing the entrainment of cold thermocline water,which contributed to Mangkhut becoming the strongest typhoon in 2018.

关键词： sea surface cooling mixed-layer depth barrier layer typhoon

Operational Characteristics of Loop Heat Pipe in Microgravity and Normal Gravity Environments

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Journal of Thermal Science 2024年第4期33卷 1394-1408页

作者： ZHONG Siyuan XIE Rongjian LI Yunfei SUN Xiaojin Shanghai Institution of Technology and Physics Shanghai200083China University of Chinese Academy of Sciences Beijing100049China Shanghai institute of satellite Engineering Shanghai200240China

The loop heat pipe(LHP)is an advanced,efficient two-phase heat transfer unit,whose operational performance may be affected by microgravity conditions in contrast to ground-based *** performance of on-orbit temperature data and ground test of a copper-propylene LHP with a condenser temperature range of 243.15 K to 303.15 K were employed to compared and *** LHP has successfully started up for more than 193 times with a good heat transfer performance and a stable start-up stabilization on-orbit under a complex orbital heating environment for more than eight *** a small heat load(10.0W),the average start-up time is 110.0 s while the start-up temperature ranges from 5.71 K-12.78 *** start-up time at large temperature differences in the high temperature zone will be higher than the time required for start-up at smaller temperature differences in the low *** the condenser temperature is 250.0 K,the stable temperature difference on orbit is 3.83 K,which is generally consistent in heat transfer compared to 2.20 K in the ground *** this paper,we can conclude that the on-orbit flight data up to now can provide a reference to the design of subsequent LHP space applications.

关键词： Loop Heat Pipe(LHP) start up microgravity on-orbit experiment

Accurate Shortwave Radiation Simulation with a Two-Layer Aerosol Model in Xinjiang Region

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Journal of Meteorological Research 2024年第1期38卷 69-87页

作者： Guan HUANG Yonghang CHEN Qiong LIU Pengtao WANG Qianshan HE Qing HE Shuai LI Weiling SHAO Ting FAN School of Tourism&Research institute of Human Geography Xi’an International Studies UniversityXi’an 710128 Center for Silk Road and Eurasian Civilization Studies Xi’an International Studies UniversityXi’an 710128 College of Environmental Science and Engineering Donghua UniversityShanghai 201620 Shanghai Meteorological Service Shanghai 200030 Shanghai Key Laboratory of meteorology and Health Shanghai 200030 Taklimakan Desert meteorology Field Experiment Station of China Meteorological Administration Institute of Desert MeteorologyUrumqi 830002 Xinjiang Climate Centre Xinjiang Meteorological ServiceUrumqi 830002

To harness the rich solar energy resources in Xinjiang Region of Northwest China,this study tries to address the issue of lack of downward surface shortwave radiation(DSSR)observations and the need to improve the accuracy of satellite retrieval and numerical simulation of DSSR under varied sky and meteorological conditions.(1)A two-layer aerosol model specific to Xinjiang was developed to capture the vertical distributions of aerosols based on multiple data sources including lidar,GPS sounding,ground meteorological observations,and profiles from the ECMWF reanalysis version 5(ERA5)*** results show that the ERA5/PBLH(planetary boundary layer height)and ERA5/ALH(aerosol layer height)could be used to establish the two-layer aerosol model and characterize the vertical distribution of aerosols in Xinjiang Region.(2)Using the Santa Barbara Discrete Atmospheric Radiative Transfer(SBDART)model,a localized inverse model of clear-sky DSSR was *** parameter adjustment and using the optimal combination of input parameters for DSSR simulation together with the two-layer aerosol model,the model-simulated DSSR(DSSRSBD)under clear-sky conditions improved significantly compared to the initial results,with all fitting indices greatly improved.(3)In addition,the study demonstrated that the impact of the two-layer aerosol model on DSSR was more pronounced under dust conditions than clear-sky conditions.(4)Using the localized clear-sky DSSR inversion model and its required parameters,simulations were also conducted to capture the spatiotemporal distribution of DSSR under clear-sky conditions in Xinjiang from 2017 to *** annual average DSSR_(SBD)under clear-sky conditions in Xinjiang during 2017–2019 was 606.78 W m^(-2),while DSSR from CERES(DSSR_(CER))under the same conditions was generally higher(703.95 W m^(-2)).(5)It is found that satellite remote sensing products experienced data loss in high-altitude snow areas,where numerical simulation technology could ser

关键词： downward surface shortwave radiation(DSSR) aerosol vertical distribution Clouds and the Earth’s Radiant Energy System(CERES) Santa Barbara Discrete Atmospheric Radiative Transfer(SBDART) Xinjiang

Distributed adaptive prescribed-time orbit containment control for satellite cluster flight

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Chinese Journal of Aeronautics 2024年第8期37卷 342-357页

作者： Tingting ZHANG Shijie ZHANG Huayi LI Xiangtian ZHAO Research Center of satellite Technology Harbin Institute of TechnologyHarbin 150080China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing 100876China

The distributed prescribed-time orbit containment control for the satellite cluster flight with multiple dynamic leaders is *** directed information communication topology between followers is taken into account in the overall *** the satellite mass is assumed to be constant,a distributed prescribed-time orbit containment controller is,firstly,presented to drive the followers into the dynamic convex hull produced by multiple ***,the parameter uncertainty is considered,and a prescribed-time sliding mode estimator is introduced to estimate the desired velocity of each *** on the estimated state,a novel distributed adaptive prescribed-time orbit containment control scheme is *** Lyapunov stability theory is utilized to prove the prescribed-time stability of the closed-loop ***,several numerical simulations and comparison of different control methods are provided to verify the effectiveness and superiority of the proposed control method.

关键词： satellite cluster Orbit containment control Prescribed-time control Parameter uncertainty Directed communication graph

System design and validation of Queqiao-2 lunar relay communication satellite

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中国空间科学技术(中英文) 2024年第5期44卷 23-39页

作者： ZHANG Lihua XIONG Liang SUN Ji CHEN Luojing XIAO Chuan ZHOU Wenyan WANG Yong LIU Wangwang GUAN Yifeng CHEN Tao YU Xiaochuan XU Jin CHEN Guohui CAO Xiaoping DFH satellite Co. Ltd. Beijing institute of Spacecraft System Engineering Beijing institute of Control Engineering Academy of Space Information Systems

In order to provide relay communication supports for future Chinese lunar exploration program, Queqiao-2 relay communication satellite was ***-2 can perform scientific observations with three kinds of scientific instruments on *** system design of Queqiao-2,including mission orbit and transfer orbit design, configuration and layout design, housekeeping and information flow design, power supply and distribution design, GNC and propulsion system design, communication links design, etc.,was accomplished through comprehensive tradeoff and evaluation on technical maturity, availability, schedule, cost, and so *** a view to reducing development risk, both the platform and relay communication payloads were developed based on significant heritage from previous Queqiao relay satellite and other relevant ***-2 features flexible system architecture to support multiple frequencies, modulations, data rates and software reconfigurations to meet new user *** to a successful launch on March 20,2024,by means of 5 orbit maneuvers, Queqiao-2 was inserted into a highly elliptical frozen mission orbit around the moon with a 24h period on *** on-orbit tests and calibrations, Queqiao-2 has possessed the capacity to provide reliable relay communication services to multiple lunar exploration missions, as well as the capacity to perform scientific *** the support of Queqiao-2,Chang′e-6 achieved its ambitious mission goal to collect and return samples from the moon′s mysterious far *** the meanwhile, Queqiao-2 has also paved the way for the following Chinese lunar exploration missions including Chang′e-7 and Chang′*** design life time of Queqiao-2 is more than 8 *** from flexibility and extensibility of relay communication system design, it is convenient to provide relay communication services for future lunar exploration missions of both China and other *** addition, innovative

关键词： lunar explorations relay communication Queqiao system design test validation