Space debris is growing dramatically with the rapid pace of human exploration of space,which seriously threatens the safety of artificial spacecraft in orbit.Therefore,the active debris removal(ADR)is important.This r...Space debris is growing dramatically with the rapid pace of human exploration of space,which seriously threatens the safety of artificial spacecraft in orbit.Therefore,the active debris removal(ADR)is important.This review aims to review the ADR methods and to advance related research in the future.The current research and development status are clearly demonstrated by mapping knowledge domain and charts.In this paper,the latest research results are classified and summarized in detail from two aspects of space debris capture and removal.The scheme comparison and evaluation of all ADR methods are performed,and the applicable scopes of various methods are summarized.Each ADR method is scored using a cobweb evaluation model based on six indicators.Future development of ADR is discussed to promote further research interest.展开更多
The HY-2 satellite carrying a satellite-borne GPS receiver is the first Chinese radar altimeter satellite, whose radial orbit determination precision must reach the centimeter level. Now HY-2 is in the test phase so t...The HY-2 satellite carrying a satellite-borne GPS receiver is the first Chinese radar altimeter satellite, whose radial orbit determination precision must reach the centimeter level. Now HY-2 is in the test phase so that the observations are not openly released. In order to study the precise orbit determination precision and procedure for HY-2 based on the satellite- borne GPS technique, the satellite-borne GPS data are simulated in this paper. The HY-2 satellite-borne GPS antenna can receive at least seven GPS satellites each epoch, which can validate the GPS receiver and antenna design. What＇s more, the precise orbit determination processing flow is given and precise orbit determination experiments are conducted using the HY-2-borne GPS data with both the reduced-dynamic method and the kinematic geometry method. With the 1 and 3 mm phase data random errors, the radial orbit determination precision can achieve the centimeter level using these two methods and the kinematic orbit accuracy is slightly lower than that of the reduced-dynamic orbit. The earth gravity field model is an important factor which seriously affects the precise orbit determination of altimeter satellites. The reduced-dynamic orbit determination experiments are made with different earth gravity field models, such as EIGEN2, EGM96, TEG4, and GEMT3. Using a large number of high precision satellite-bome GPS data, the HY-2 precise orbit determination can reach the centimeter level with commonly used earth gravity field models up to above 50 degrees and orders.展开更多
Only one-dimensional (1D)deformation along the radar line of sight (LOS)can be obtained using differential interferometry synthetic aperture radar (D-InSAR),and D-InSAR observation is insensitive to deformation in the...Only one-dimensional (1D)deformation along the radar line of sight (LOS)can be obtained using differential interferometry synthetic aperture radar (D-InSAR),and D-InSAR observation is insensitive to deformation in the north direction.This study inferred three-dimensional (3D)deformation of a mining subsidence basin by combining the north-south deformation predicted by a probability integral method with the LOS deformation obtained by D-InSAR.The 15235 working face in Fengfeng mining area (Hebei Province,China)was used as the object of study.The north-south horizontal movement was predicted by the probability integral method according to the site's geological and mining conditions.Then,the vertical and east-west deformation fields were solved by merging ascend-orbit RadarSAT-2, descend-orbit TerraSAR,and predicted north-south deformation based on a least squares method.Comparing with the leveling data,the results show that the vertical deformation accuracy of the experimental method is better than the inversed vertical deformation neglecting the horizontal deformation.Finally,the impact of the relationship between the azimuth of the working face and the SAR imaging geometry on the monitoring of the mining subsidence basin was analyzed.The results can be utilized in monitoring mining subsidence basins by single SAR image sources.展开更多
We investigate the ground states of spin-orbit coupled spin-1 Bose-Einstein condensates in the presence of Zeeman splitting.By introducing the generalized momentum operator,the linear version of the system is solved e...We investigate the ground states of spin-orbit coupled spin-1 Bose-Einstein condensates in the presence of Zeeman splitting.By introducing the generalized momentum operator,the linear version of the system is solved exactly,yielding a set of Bessel vortices.Additionally,based on linear solution and using variational approximation,the solutions for the full nonlinear system and their ground state phase diagrams are derived,including the vortex states with quantum numbers m=0,1,as well as mixed states.In this work,mixed states in spin-1 spin-orbit coupling(SOC)BEC are interpreted for the first time as weighted superpositions of three vortex states.Furthermore,the results also indicate that under strong Zeeman splitting,the system cannot form localized states.The variational solutions align well with numerical simulations,showing stable evolution and meeting the criteria for long-term observation in experiments.展开更多
基金This work was supported by the National Key R&D Program of China(Grant No.2018YFB1304600)the National Natural Science Foundation of China(Grant No.51775541)+2 种基金the CAS Interdisciplinary Innovation Team(Grant No.JCTD-2018-11)the State Key Laboratory of Robotics Foundation(Grant No.Y91Z0303)the Hundred-Talent Program(Chinese Academy of Sciences)(Grant No.Y8A3210304).
文摘Space debris is growing dramatically with the rapid pace of human exploration of space,which seriously threatens the safety of artificial spacecraft in orbit.Therefore,the active debris removal(ADR)is important.This review aims to review the ADR methods and to advance related research in the future.The current research and development status are clearly demonstrated by mapping knowledge domain and charts.In this paper,the latest research results are classified and summarized in detail from two aspects of space debris capture and removal.The scheme comparison and evaluation of all ADR methods are performed,and the applicable scopes of various methods are summarized.Each ADR method is scored using a cobweb evaluation model based on six indicators.Future development of ADR is discussed to promote further research interest.
基金supported partially by the National Natural Science Foundation of China (Nos. 40974004 and 40974016)Key Laboratory of Dynamic Geodesy of CAS, China (No. L09-01) R&I Team Support Program and the Graduate Science and Technology Foundation of SDUST, China (No. YCA110403)
文摘The HY-2 satellite carrying a satellite-borne GPS receiver is the first Chinese radar altimeter satellite, whose radial orbit determination precision must reach the centimeter level. Now HY-2 is in the test phase so that the observations are not openly released. In order to study the precise orbit determination precision and procedure for HY-2 based on the satellite- borne GPS technique, the satellite-borne GPS data are simulated in this paper. The HY-2 satellite-borne GPS antenna can receive at least seven GPS satellites each epoch, which can validate the GPS receiver and antenna design. What＇s more, the precise orbit determination processing flow is given and precise orbit determination experiments are conducted using the HY-2-borne GPS data with both the reduced-dynamic method and the kinematic geometry method. With the 1 and 3 mm phase data random errors, the radial orbit determination precision can achieve the centimeter level using these two methods and the kinematic orbit accuracy is slightly lower than that of the reduced-dynamic orbit. The earth gravity field model is an important factor which seriously affects the precise orbit determination of altimeter satellites. The reduced-dynamic orbit determination experiments are made with different earth gravity field models, such as EIGEN2, EGM96, TEG4, and GEMT3. Using a large number of high precision satellite-bome GPS data, the HY-2 precise orbit determination can reach the centimeter level with commonly used earth gravity field models up to above 50 degrees and orders.
基金the National Natural Science Foundation of China (Grant Nos.41272389 and 41604005)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (No.SZBF2011-6-B35)+2 种基金Special Fund for Public Projects of National Administration of Surveying, Mapping,and Geoinformation of China (No.201412016)Project supported by the Basic Research Project of Jiangsu Province (Natural Science Foundation)(No.BK20160218)the State Key Laboratory of Geohazard Prevention and Geoenviromnent Protection (Chengdu University of Technology)(No.SKLGP2016K008).
文摘Only one-dimensional (1D)deformation along the radar line of sight (LOS)can be obtained using differential interferometry synthetic aperture radar (D-InSAR),and D-InSAR observation is insensitive to deformation in the north direction.This study inferred three-dimensional (3D)deformation of a mining subsidence basin by combining the north-south deformation predicted by a probability integral method with the LOS deformation obtained by D-InSAR.The 15235 working face in Fengfeng mining area (Hebei Province,China)was used as the object of study.The north-south horizontal movement was predicted by the probability integral method according to the site's geological and mining conditions.Then,the vertical and east-west deformation fields were solved by merging ascend-orbit RadarSAT-2, descend-orbit TerraSAR,and predicted north-south deformation based on a least squares method.Comparing with the leveling data,the results show that the vertical deformation accuracy of the experimental method is better than the inversed vertical deformation neglecting the horizontal deformation.Finally,the impact of the relationship between the azimuth of the working face and the SAR imaging geometry on the monitoring of the mining subsidence basin was analyzed.The results can be utilized in monitoring mining subsidence basins by single SAR image sources.
基金supported by the Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515110198)the Natural Science Foundation of Guangdong Province,China(Grant Nos.2024A1515030131 and 2021A1515010214)+2 种基金the National Natural Science Foundation of China(Grant Nos.12274077,11905032,and 12475014)the Research Fund of the Guangdong-Hong Kong-Macao Joint Laboratory for Intelligent Micro-Nano Optoelectronic Technology(Grant No.2020B1212030010)the Israel Science Foundation(Grant No.1695/22).
文摘We investigate the ground states of spin-orbit coupled spin-1 Bose-Einstein condensates in the presence of Zeeman splitting.By introducing the generalized momentum operator,the linear version of the system is solved exactly,yielding a set of Bessel vortices.Additionally,based on linear solution and using variational approximation,the solutions for the full nonlinear system and their ground state phase diagrams are derived,including the vortex states with quantum numbers m=0,1,as well as mixed states.In this work,mixed states in spin-1 spin-orbit coupling(SOC)BEC are interpreted for the first time as weighted superpositions of three vortex states.Furthermore,the results also indicate that under strong Zeeman splitting,the system cannot form localized states.The variational solutions align well with numerical simulations,showing stable evolution and meeting the criteria for long-term observation in experiments.
