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spacecraft angular velocity estimation method using optical flow of stars

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Science China(Information Sciences) 2018年第11期61卷 99-112页

作者： Xiaolin NING Zonghe DING Pingping CHEN Weiren WU Jiancheng FANG Gang LIU School of Instrumentation Science & Opto-electronics Engineering Beihang University lunar exploration and space program center China National Space Administration

Angular velocity is a crucial parameter for spacecraft navigation, which, at present, is mainly obtained by using gyroscopes. Several studies have been performed on angular velocity estimation using star sensors when data from gyroscopes are not available. Most of the previous angular velocity estimation methods using star sensors are based on information on the attitude or star vector measurements. In this paper,an angular velocity estimation method using the optical flow(OF) directly from the star images is proposed,which, unlike the previous methods, requires star coordinates in two consecutive images only. Because the procedure of star identification is eliminated, the corresponding high computation requirement is *** demonstrate that the proposed method has a robust performance in terms of computational cost and the number of stars in the field of view(FOV) compared with the previous methods. Finally, certain affecting factors are analyzed, including lens distortion, star senor instantaneous FOV(IFOV), star number,and accuracy of the star sensor.

关键词： angular velocity star sensor optical flow star images Kalman filter

Angular velocity estimation using characteristics of star trails obtained by star sensor for spacecraft

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Science China(Information Sciences) 2021年第1期64卷 201-214页

作者： Xiaolin NING Pingping CHEN Yueqing HUANG Weiren WU Jiancheng FANG School of Instrumentation Science & Opto-electronics Engineering Beihang University lunar exploration and space program center China National Space Administration

Many studies have been conducted about angular velocity estimation using star sensors, and fairly good performance is achieved when the spacecraft is working at low-dynamic environments. However,when the spacecraft rotates at a large angular velocity, the star image will become blurred, which makes it difficult to identify and recognize star centroids, which, in turn, reduces the accuracy of angular velocity estimation. Therefore, to solve the problem with angular velocity estimation in highly dynamic situations,this research studies a method of angular velocity estimation using blurred star images. The length and ending point coordinates of star trails obtained from these blurred star images are used for a series of processes, which includes the pre-processing of blurred star images, determination of starting and ending points, thinning and selection of star trails, and calculation of trail lengths. Simulations show that the effectiveness of the proposed method in highly dynamic situations and the angular velocity estimation errors in constant and sinusoidal variation are reduced by at least 66% and 62%, respectively, compared with those of the traditional method.

关键词： angular velocity estimation star sensor blurred star images star trail characteristics unscented Kalman filter

Observations and interpretations of geomorphologic features in the Tianwen-1 landing area on Mars by using orbital imagery data

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Earth and Planetary Physics 2023年第3期7卷 331-346页

作者： Hai Huang Xing Wang Yuan Chen Qing Zhang FeiYue Zhao Xin Ren XingGuo Zeng Wei Yan WangLi Chen Bin Liu DaWei Liu LianBo Fu JianJun Liu Key Laboratory of lunar and Deep space exploration National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of Astronomy and space Science University of Chinese Academy of SciencesBeijing 100049China

China’s first Mars exploration mission,Tianwen-1,successfully landed in southern Utopia Planitia on Mars on May 15,*** work presents a detailed investigation of the geologic context of the landing area surface for this mission based on orbital remotesensing *** constructed a geomorphologic map for the Tianwen-1 landing *** of our detailed geomorphologic map show several major landforms within the landing area,including rampart craters,mesas,troughs,cones,and *** of materials on the landing area surface indicates that most of the landing area is covered by Martian *** aeolian ridges are widely distributed within the landing area,indicating the surface contexts were(and still are)modified by regional *** addition,a crater counting analysis indicates the landing area has an absolute model age of~3.3 Ga and that a later resurfacing event occurred at~1.6 ***,we outline four formational scenarios to test the formation mechanisms for the geomorphologic features on the landing area *** most likely interpretation to explain the existence of the observed surface features can be summarized as follows:A thermal influence may have played an important role in the formation of the surface geomorphologic features;thus,igneous-related processes may have occurred in the landing *** ice may also have been involved in the construction of the primordial surface *** resurfacing events and aeolian processes buried and modified the primordial surface.

关键词： Mars Utopia Planitia Tianwen-1 geomorphologic features water ice heat source

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重返月球-月球探测新视角（英文）

Science Bulletin 2024年第13期 2136-2148页

作者：林杨挺杨蔚张辉惠鹤九胡森肖龙刘建忠肖智勇岳宗玉张金海刘洋杨晶林红磊张爱铖郭弟均芶盛徐琳何雨旸张贤国秦礼萍凌宗成李雄耀杜爱民贺怀宇张鹏曹晋滨李献华 School of space and Environment Beihang University Key Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences State Key Laboratory for Mineral Deposits Research and School of Earth Sciences and Engineering Nanjing University State Key Laboratory of Geological Processes and Mineral Resources School of Earth Sciences China University of Geosciences Institute of Geochemistry Chinese Academy of Sciences Planetary Environmental and Astrobiological Research Laboratory School of Atmospheric Sciences Sun Yat-sen University National space Science center Chinese Academy of Sciences Deep space exploration Laboratory/CAS Key Laboratory of Crust-Mantle Materials and Environments University of Science and Technology of China Shandong Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment Institute of Space Sciences Shandong University Technology and Engineering center for space Utilization Chinese Academy of Sciences

lunar exploration is deemed crucial for uncovering the origins of the Earth-Moon system and is the first step for advancing humanity's exploration of deep space. Over the past decade, the Chinese lunar exploration program(CLEP), also known as the Chang'e(CE) Project, has achieved remarkable *** has successfully developed and demonstrated the engineering capability required to reach and return from the lunar surface. Notably, the CE Project has made historic firsts with the landing and on-site exploration of the far side of the Moon, along with the collection of the youngest volcanic samples from the Procellarum KREEP Terrane. These achievements have significantly enhanced our understanding of lunar evolution. Building on this success, China has proposed an ambitious crewed lunar exploration strategy,aiming to return to the Moon for scientific exploration and utilization. This plan encompasses two primary phases: the first crewed lunar landing and exploration, followed by a thousand-kilometer scale scientific expedition to construct a geological cross-section across the lunar surface. Recognizing the limitations of current lunar exploration efforts and China's engineering and technical capabilities, this paper explores the benefits of crewed lunar exploration while leveraging synergies with robotic exploration. The study refines fundamental lunar scientific questions that could lead to significant breakthroughs, considering the respective engineering and technological requirements. This research lays a crucial foundation for defining the objectives of future lunar exploration, emphasizing the importance of crewed missions and offering insights into potential advancements in lunar science.

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Gravitational Deformation Measurement Method for the Main Reflector and Sub-reflector of the 70 m Antenna by Laser Scanner

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Research in Astronomy and Astrophysics 2022年第9期22卷 1-9页

作者： Lian-Bo Fu Jian-Jun Liu Wei Yan De-Qing Kong Xin Ren Chen-Di Liu Hong-Bo Zhang Key Laboratory of lunar and Dep space exploration National Astronomical ObservatoriesChinese Academy of SciencesBejing 100101China Urunaivreyr of Chinese Academy of Sciences Beijing 100049China

Large antennas play an important role in deep space exploration and astronomical research. However, their performances are inevitably affected by the main reflector surface deformation and sub-reflector displacement resulting from the factors of wind, temperature, and gravity, among which the effect of gravity is especially pronounced. In this work, a three-dimensional laser scanner was employed to measure the main reflector and subreflector gravitational deformation of the Tianjin 70 m antenna at different elevation angles. Here, we solved the antenna main reflector deformation and sub-reflector displacement, and analyzed the deformation law of the antenna under the action of gravity. A new measurement method of antenna main reflector deformation and subreflector displacement is realized by mutual verification of the measured results and theoretical simulations. This method will help to improve the antenna performance and provide a reference to optimize the design of largeaperture antennas.

关键词： telescopes techniques:radar astronomy planets and satellites:detection

Response of InSight resonance modes to environmental factors on Mars

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Earth and Planetary Physics 2024年第4期8卷 579-588页

作者： LiFei Tian HuaJian Yao Laboratory of Seismology and Physics of Earth’s Interior School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China Chinese Academy of Sciences center for Excellence in Comparative Planetology University of Science and Technology of ChinaHefei 230026China Mengcheng National Geophysical Observatory University of Science and Technology of ChinaMengcheng 230026China

The InSight(Interior exploration using Seismic Investigations,Geodesy,and Heat Transport)mission has recorded continuous ambient noise signals with many spectral peaks since its landing in *** majority of these peaks are modes produced by instrumental vibrations and are associated with environmental factors,such as temperature and wind energy *** how these modes react under various conditions is crucial because it aids in identifying their *** this study,we analyzed the three-component spectra of InSight recordings from sols 184–738 and obtained the horizontal-to-vertical spectral ratio(HVSR,also known as H/V)curves for different time *** primary modes,such as those at 3.3 and 4.1 Hz,exhibited different behaviors,suggesting diverse *** modes were sensitive to low temperature and some were sensitive to high ***,we investigated the influence of wind and temperature on the H/V *** peak frequency was mainly affected by temperature,whereas the H/V value was not associated with the temperature or wind *** these modes and elucidating their origins are significant for processing signals from InSight and can provide valuable guidance for designing future planetary seismometers.

关键词： Mars InSight spectral peaks H/V curve

Theoretical study of the ionospheric dynamo region inside the South Atlantic Anomaly

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Earth and Planetary Physics 2023年第1期7卷 84-92页

作者： SiQi Yi XiaoJun Xu ZiLu Zhou Qing Chang Xing Wang Lei Luo PeiShan He Hui Li State Key Laboratory of lunar and Planetary Sciences Macao University of Science and TechnologyTaipa Macao 999078China CNSA Macao center for space exploration and Science Taipa Macao 999078China State Key Laboratory of space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

The South Atlantic Anomaly(SAA)is a region where the geomagnetic field is significantly lower than that of the surrounding *** the basis of the models of CHAOS-7.8,Mass Spectrometer Incoherent Scatter Model(NRLMSISE-00),and International Reference Ionosphere 2016(IRI-2016),we theoretically investigated the lower and upper boundaries of the ionospheric dynamo region inside the *** the ionospheric dynamo region,electrons are coupled with magnetic field lines,whereas ions are decoupled from magnetic field *** results showed that the ionospheric dynamo region inside the SAA is higher and larger than that outside the *** also studied the boundary variations of the dynamo region inside the SAA depending on the seasons and solar *** found that the dynamo region inside the SAA is the highest and largest in the summer of the southern hemisphere at solar *** larger and higher altitude range of the ionospheric dynamo region in the SAA can contribute to the stronger ionospheric currents in this region.

关键词： South Atlantic Anomaly ionospheric dynamo region ionosphere

The behavior of a lithospheric magnetization and magnetic field model

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Earth and Planetary Physics 2023年第1期7卷 66-73页

作者： PengFei Liu Yi Jiang Qing Yan Ann MHirt State Key Laboratory of lunar and Planetary Sciences Macao University of Science and TechnologyMacaoChina CNSA Macao center for space exploration and Science MacaoChina Institute of Geophysics ETH ZürichSonneggstrasse 5CH-8095 ZürichSwitzerland

The Earth’s“lithosphere”is its outer shell,made up of the Earth’s crust and outermost *** part of the Earth’s magnetic field that originates in the lithosphere consists of a superposition of magnetic anomalies with a broad spectrum of sizes and intensities,which arise from geological and tectonic *** lithospheric magnetic field is known from surface observations,and on larger scales from above-surface *** increase in recent decades of satellites dedicated to measuring the Earth’s magnetic field has improved significantly our models of the Earth’s magnetic *** on these increasing observations,a number of comprehensive field models have been constructed,some of which focus solely on the lithosphere,such as the MF model *** present a map of lithospheric magnetic anomalies at 400 km altitude,based on a vertically integrated magnetization *** height was chosen because it is the expected orbital altitude of the Macao Science Satellite-1(MSS-1)*** model presented herein indicates that the amplitude of the lithospheric anomalies at 400 km altitude is between-14.8 n T and 18.2 n *** information is useful because it provides a reference for the lithospheric source of the Earth’s magnetic field that contributes to the magnetic measurements made from satellite *** low inclination orbit of the MSS-1 mission will provide information that is sensitive to lateral variation within the lithosphere;these variations arise from plate tectonic features with longitudinal *** conclusion,the new MSS-1mission will provide valuable information in detecting compositional variations in the lithosphere,and in delineating large-scale geological structures.

关键词： vertically integrated magnetization lithospheric magnetic field field model MSS-1

撞击过程对月表氧逸度的改造:来自嫦娥五号月壤中撞击玻璃珠的启示

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Science Bulletin 2024年第10期69卷 1495-1505页

作者：庞润连杨晶李瑞刘世荣李琼朱丹杜蔚刘耘 State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China center for lunar and Planetary Sciences Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 101408China center for Excellence in Comparative Planetology Chinese Academy of SciencesHefei 230026China Research center for Planetary Science College of Earth ScienceChengdu University of TechnologyChengdu 610059China

lunar materials are overall more reducing compared with their terrestrial counterparts,but the mechanism remains to be *** this study,we present a possible explanation for the changes in redox state of the lunar regolith caused by impact events,based on our investigations of the impact glass beads from Chang’e-5 *** glass beads contain iron metal grains and show concentration gradients of FeO and K_(2)O(with or without Na_(2)O)from their rims to *** compositional profiles exhibit errorfunction-like shapes,which indicates a diffusion-limited *** numerical modeling results suggest that the iron metal grains on the surface of the glass beads were generated through the reduction of FeO by elemental K and(or)Na produced during the impact ***,the iron metal grains inside the bead may have formed due to oxygen diffusion driven by redox potential ***,our study suggests that impact processes intensify the local reducing conditions,as evidenced by the presence of calcium sulfide particles within troilite grains that coexist with iron metal grains on the surface of the glass *** study provides insights into the oxygen diffusion kinetics during the formation of iron metal spherules and sheds light on the changes in redox conditions of lunar materials caused by impact events.

关键词： Chang’e-5 lunar sample Glass beads Impact Oxygen fugacity Redox change