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The deconvolution of lunar brightness temperature based on the maximum entropy method using Chang'e-2 microwave data

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Research in Astronomy and Astrophysics 2015年第2期15卷 293-304页

作者： Shu-Guo Xing Yan Su Jian-Qing Feng chun-lai li National Astronomical Observatories Chinese Academy of Sciences

A passive and multi-channel microwave sounder onboard the Chang＇e-2 orbiter has successfully acquired microwave observations of the lunar surface and subsurface structure. Compared with the Chang＇e-1 orbiter, the Chang＇e-2 orbiter obtained more accurate and comprehensive microwave brightness temperature data, which are helpful for further research. Since there is a close relationship between mi- crowave brightness temperature data and some related properties of the lunar regolith, such as the thickness, temperature and dielectric constant, precise and high resolution brightness temperature data are necessary for such research. However, through the detection mechanism of the microwave sounder, the brightness temperature data ac- quired from the microwave sounder are weighted by the antenna radiation pattern, so the data are the convolution of the antenna radiation pattern with the lunar brightness temperature. In order to obtain the real lunar brightness temperature, a deconvolution method is needed. The aim of this paper is to solve the problem associated with per- forming deconvolution of the lunar brightness temperature. In this study, we introduce the maximum entropy method （MEM） to process the brightness temperature data and achieve excellent results. The paper mainly includes the following aspects： first, we introduce the principle of the MEM; second, through a series of simulations, the MEM has been verified as an efficient deconvolution method; and third, the MEM is used to process the Chang＇e-2 microwave data and the results are significant.

关键词： space vehicles instruments: microwave sounder Moon: brightness temperature methods: maximum entropy method

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Reconstructing the landing trajectory of the CE-3 lunar probe by using images from the landing camera

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Research in Astronomy and Astrophysics 2014年第12期14卷 1530-1542页

作者： Jian-Jun liu Wei Yan chun-lai li Xu Tan Xin Ren ling-li Mu Key Laboratory of Lunar and Deep Space Exploration National Astronomical ObservatoriesChinese Academy of Sciences

An accurate determination of the landing trajectory of Chang＇e-3 （CE-3） is significant for verifying orbital control strategy, optimizing orbital planning, accu- rately determining the landing site of CE-3 and analyzing the geological background of the landing site. Due to complexities involved in the landing process, there are some differences between the planned trajectory and the actual trajectory of CE-3. The land- ing camera on CE-3 recorded a sequence of the landing process with a frequency of 10 frames per second. These images recorded by the landing camera and high-resolution images of the lunar surface are utilized to calculate the position of the probe, so as to reconstruct its precise trajectory. This paper proposes using the method of trajectory reconstruction by Single Image Space Resection to make a detailed study of the hov- ering stage at a height of 100 m above the lunar surface. Analysis of the data shows that the closer CE-3 came to the lunar surface, the higher the spatial resolution of im- ages that were acquired became, and the more accurately the horizontal and vertical position of CE-3 could be determined. The horizontal and vertical accuracies were 7.09 m and 4.27 m respectively during the hovering stage at a height of 100.02 m. The reconstructed trajectory can reflect the change in CE-3＇s position during the powered descent process. A slight movement in CE-3 during the hovering stage is also clearly demonstrated. These results will provide a basis for analysis of orbit control strategy, and it will be conducive to adjustment and optimization of orbit control strategy in follow-up missions.

关键词： Moon - methods: data analysis - techniques: image processing

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The penetrating depth analysis of Lunar Penetrating Radar onboard Chang＇e-3 rover

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Research in Astronomy and Astrophysics 2017年第5期17卷 79-90页

作者： Shu-Guo Xing Yan Su Jian-Qing Feng Shun Dai Yuan Xiao chun-Yu Ding chun-lai li National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China University of Chinese Academy of Sciences Beijing 100049 China

Lunar Penetrating Radar（LPR） has successfully been used to acquire a large amount of scientific data during its in-situ detection. The analysis of penetrating depth can help to determine whether the target is within the effective detection range and contribute to distinguishing useful echoes from ***, this study introduces two traditional methods, both based on a radar transmission equation, to calculate the penetrating depth. The only difference between the two methods is that the first method adopts system calibration parameters given in the calibration report and the second one uses high-voltage-off radar data. However, some prior knowledge and assumptions are needed in the radar equation and the accuracy of assumptions will directly influence the final results. Therefore, a new method termed the Correlation Coefficient Method（CCM） is provided in this study, which is only based on radar data without any a priori assumptions. The CCM can obtain the penetrating depth according to the different correlation between reflected echoes and noise. To be exact, there is a strong correlation in the useful reflected echoes and a random correlation in the noise between adjacent data traces. In addition, this method can acquire a variable penetrating depth along the profile of the rover, but only one single depth value can be obtained from traditional methods. Through a simulation, the CCM has been verified as an effective method to obtain penetration depth. The comparisons and analysis of the calculation results of these three methods are also implemented in this study. Finally, results show that the ultimate penetrating depth of Channel 1 and the estimated penetrating depth of Channel 2 range from 136.9 m to 165.5 m（ε_r = 6.6） and from 13.0 m to 17.5 m（ε_r = 2.3）, respectively.

关键词： penetrating Lunar rover lunar assumptions calibration ultimate traces Correlation verified

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Data processing and error analysis for the CE-1 Lunar microwave radiometer

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Research in Astronomy and Astrophysics 2013年第3期13卷 359-372页

作者： Jian-Qing Feng Yan Su Jian-Jun liu Yong-liao Zou chun-lai li National Astronomical Observatories Chinese Academy of Sciences

The microwave radiometer （MRM） onboard the Chang＇ E-1 （CE-I） lu- nar orbiter is a 4-frequency microwave radiometer, and it is mainly used to obtain the brightness temperature （TB） of the lunar surface, from which the thickness, temperature, dielectric constant and other related properties of the lunar regolith can be derived. The working mode of the CE-1 MRM, the ground calibration （including the official calibration coefficients）, as well as the acquisition and processing of the raw data are introduced. Our data analysis shows that TB increases with increasing frequency, decreases towards the lunar poles and is significantly affected by solar illumination. Our analysis also reveals that the main uncertainty in TB comes from ground calibration.

关键词： space vehicles -- instruments: microwave radiometer -- Moon: bright-ness temperature -- method: data processing -- error analysis

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Terrain reconstruction from Chang'e-3 PCAM images

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Research in Astronomy and Astrophysics 2015年第7期15卷 1057-1067页

作者： Wen-Rui Wang Xin Ren Fen-Fei Wang Jian-Jun liu chun-lai li National Astronomical Observatories Chinese Academy of Sciences

The existing terrain models that describe the local lunar surface have limited resolution and accuracy, which can hardly meet the needs of rover navigation,positioning and geological analysis. China launched the lunar probe Chang＇e-3 in December, 2013. Chang＇e-3 encompassed a lander and a lunar rover called ＂Yutu＂（Jade Rabbit）. A set of panoramic cameras were installed on the rover mast. After acquiring panoramic images of four sites that were explored, the terrain models of the local lunar surface with resolution of 0.02 m were reconstructed. Compared with other data sources, the models derived from Chang＇e-3 data were clear and accurate enough that they could be used to plan the route of Yutu.

关键词： space vehicles: rover -- space vehicles: instruments: panoramic camera-- methods: terrain reconstruction -- techniques: image processing: orthoimage

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Preface: The Chang'e-3 lander and rover mission to the Moon

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Research in Astronomy and Astrophysics 2014年第12期14卷 1511-1513页

作者： Wing-Huen Ip Jun Yan chun-lai li Zi-Yuan Ouyang Institute of Astronomy National Central University National Astronomical Observatories Chinese Academy of Sciences

The Chang＇e-3 （CE-3） lander and rover mission to the Moon was an in- termediate step in China＇s lunar exploration program, which will be followed by a sample return mission. The lander was equipped with a number of remote-sensing instruments including a pair of cameras （Landing Camera and Terrain Camera） for recording the landing process and surveying terrain, an extreme ultraviolet camera for monitoring activities in the Earth＇s plasmasphere, and a first-ever Moon-based ultravi- olet telescope for astronomical observations. The Yutu rover successfully carried out close-up observations with the Panoramic Camera, mineralogical investigations with the VIS-NIR Imaging Spectrometer, study of elemental abundances with the Active Particle-induced X-ray Spectrometer, and pioneering measurements of the lunar sub- surface with Lunar Penetrating Radar. This special issue provides a collection of key information on the instrumental designs, calibration methods and data processing pro- cedures used by these experiments with a perspective of facilitating further analyses of scientific data from CE-3 in preparation for future missions.

关键词： Chang'e-3 - Moon lander - rover - radar - lunar telescope

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Surface decoration of mesocarbon microbeads with multifunctional TiNbO_(4-x)@C coating layer as high rate and stable anode of li-ion batteries

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Rare Metals 2024年第5期43卷 2053-2066页

作者： Jia-Mei lai Zhi-Min Zou Yu Bai Yu-Tao Xing chun-Hai Jiang Fujian Provincial Key Laboratory of Functional Materials and Applications Institute of Advanced Energy MaterialsSchool of Materials Science and EngineeringXiamen University of TechnologyXiamen 361024China Shanghai XFH Science and Technology Development Co. Ltd.Shanghai 200949China Fujian XFH New Energy Materials Co. Ltd.Yong'an 366000China Shenzhen XFH Science and Technology Co. Ltd.Shenzhen 518071China Laboratorio de Microscopia Eletronica de Alta Resolucao Centro de Caracterizagao Avangada Para a Industria de Petroleo(LaMAR/CAIPE)Universidade Federal FluminenseNiteroiRJ 24210-346Brazil

Surface modification of graphite anode with electroactive matters has been proven of a more practical strategy in enhancing the performance of li-ion batteries than exploring alternative novel anode ***,rutile TiNbO_(4-x) nanoparticles with a tunnel structure are employed as multifunctional decoration substances in combination with a carbon coating layer to improve the rate and cycle properties of mesocarbon microbeads(MCMBs).As compared to pristine MCMB,the li^(+)diffusion coefficients of the composite anodes are enhanced due to the synergistic effect of TiNbO_(4-x)@***,the overcharge and voltage polarization of the composite anodes at high rate are obviously minimized due to the current sharing effect of the high-potential TiNbO_(4-x).Moreover,the amorphous li_(y)TiNbO_(4-x) converted from TiNbO_(4-x) in the initial lithiation process can deliver pseudocapacitive capacity to the composite anodes from the second *** of these functions of TiNbO_(4-x)@Ccoating layer have directly contributed to the improved rate and cycle performance of the MCMB/TiNbO_(4-x)@C composite *** one containing 12.0 wt%TiNbO_(4-x) exhibits a high reversible specific capacity of 118 m Ah·g^(-1)at 10C(1C=372 m A·g^(-1)),together with a high capacity retention of 90.9%after 300 cycles at 3C,which are all much superior to those of pristine MCMB.

关键词： li-ion batteries MCMB TiNbO_(4-x)@C Surface decoration Rate capability

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New radio observations of the Moon at L band

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Research in Astronomy and Astrophysics 2012年第9期12卷 1297-1312页

作者： Xi-Zhen Zhang Andrew Gray Yan Su Jun-Duo li Tom Landecker Hong-Bo Zhang chun-lai li National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China zxz @ nao. cas. cn Dominion Radio Astrophysical Observatory Penticton BC V2A 6K3 Canada

We present results of new radio observations of the Moon at L band with the synthesis telescope of the Dominion Radio Astrophysical Observatory Synthesis Telescope. The resolution and temperature sensitivity of the observations are 159 × 87 and 1.7K, respectively. The main results are: (1) the lunar brightness temperature averaged over the whole disk is about 233K while the average brightness temperature for the four quadrants are 228.1K (NE), 239.7K (NW), 233.9K (SW) and 228.8K (SE). The observations reveal large temperature and spatial variations on the Moon for the first time. The highest brightness temperature is about 257 K and it is located along the lunar equator, to the west. The total uncertainty is about 5% due to the absolute accuracy of the fluxes of the primary calibrators; (2) the total degree of po- larization is about 6%. Both polarization intensity and degree of polarization increase from the disk’s center to the limb, and the distribution of the degree of polarization along the limb is not uniform; (3) the new data are used to study the properties of regolith, such as dielectric constant and thickness distribution. The results show that the lunar regolith’s thickness increases from the NW (mare area) to the SE (highland area) regions on the lunar surface.

关键词： techniques: high angular resolution-imaging processing — radio contin- uum: Moon

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The New Wuqing 70 m Radio Telescope and Measurements of Main Electronic Properties in the X-band

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Research in Astronomy and Astrophysics 2022年第3期22卷 122-132页

作者： De-Qing Kong chun-lai li Hong-Bo Zhang Yan Su Jian-Jun liu Xin-Ying Zhu Jun-Duo li Xi-Ping Xue Chen li Key Laboratory of Lunar and Deep Space Exploration National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

The new Wuqing 70 m radio telescope is first used for the downlink data reception in the first Mars exploration mission of China,and will be used for the other deep space communications and radio astronomical observations in the *** main specifications and measurement results of some properties in the X-band are introduced in this paper,such as pointing calibration,gain and efficiency,system noise temperature,system equivalent flux density,and variations with *** 23 parameters pointing calibration model considering the atmospheric refraction correction in real time is presented in the telescope,and the pointing accuracy reaches 570 in azimuth direction and 607 in elevation direction for different weather *** than 62%efficiencies are achieved at full elevation range,and more than 70%in the *** system equivalent flux density of the X-band in the mid-elevation reaches 26 Jy.

关键词： telescopes astronomical instrumentation methods and techniques atmospheric effects

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Time series data correction for the Chang'E-1 gamma-ray spectrometer

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Research in Astronomy and Astrophysics 2011年第6期11卷 737-750页

作者： li-Yan Zhang Yong-liao Zou Jian-Zhong liu Jian-Jun liu Ji Shen ling-li Mu Xin Ren Wei-Bin Wen chun-lai li National Astronomical Observatories Chinese Academy of SciencesBeijing 100012China Graduate University of Chinese Academy of Sciences Beijing 100049China

The main goal of the gamma-ray spectrometer（GRS） onboard Chang＇E1（CE-1） is to acquire global maps of elemental abundances and their distributions on the moon,since such maps will significantly improve our understanding of lunar formation and *** derive the elemental maps and enable research on lunar formation and evolution,raw data that are received directly from the spacecraft must be converted into time series corrected gamma-ray *** data correction procedures for the CE-1 GRS time series data are thoroughly *** processing procedures to create the time series gamma-ray spectra described here include channel processing,optimal data selection,energy calibration,gain correction,dead time correction,geometric correction,orbit altitude normalization,eliminating unusable data and galactic cosmic ray ***,descriptions are also given on data measurement uncertainties,which will help the interested scientists to understand and estimate various uncertainties associated with the above data processing.

关键词： instrumentation:spectrographs(gamm-ray spectrometer)-gammarays:observations-methods:data analysis

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