Ground-based synthetic aperture radar(GB-SAR) has been successfully applied to the ground deformation monitoring.However, due to the short length of the GB-SAR platform, the scope of observation is largely limited. Th...Ground-based synthetic aperture radar(GB-SAR) has been successfully applied to the ground deformation monitoring.However, due to the short length of the GB-SAR platform, the scope of observation is largely limited. The practical applications drive us to make improvements on the conventional linear rail GB-SAR system in order to achieve larger field imaging. First, a turntable is utilized to support the rotational movement of the radar.Next, a series of high-squint scanning is performed with multiple squint angles. Further, the high squint modulation phase of the echo data is eliminated. Then, a new multi-angle imaging method is performed in the wave number domain to expand the field of view. Simulation and real experiments verify the effectiveness of this method.展开更多
In recent years, ground-based micro-deformation monitoring radar has attracted much attention due to its excellent monitoring capability. By controlling the repeated campaigns of the radar antenna on a fixed track, gr...In recent years, ground-based micro-deformation monitoring radar has attracted much attention due to its excellent monitoring capability. By controlling the repeated campaigns of the radar antenna on a fixed track, ground-based micro-deformation monitoring radar can accomplish repeat-pass interferometry without a space baseline and thus obtain highprecision deformation data of a large scene at one time. However, it is difficult to guarantee absolute stable installation position in every campaign. If the installation position is unstable, the stability of the radar track will be affected randomly, resulting in time-varying baseline error. In this study, a correction method for this error is developed by analyzing the error distribution law while the spatial baseline is unknown. In practice, the error data are first identified by frequency components, then the data of each one-dimensional array(in azimuth direction or range direction) are grouped based on numerical distribution period, and finally the error is corrected by the nonlinear model established with each group.This method is verified with measured data from a slope in southern China, and the results show that the method can effectively correct the time-varying baseline error caused by rail instability and effectively improve the monitoring data accuracy of groundbased micro-deformation radar in short term and long term.展开更多
When multiple ground-based radars(GB-rads)are utilized together to resolve three-dimensional(3-D)deformations,the resolving accuracy is related with the measurement geometry constructed by these radars.This paper focu...When multiple ground-based radars(GB-rads)are utilized together to resolve three-dimensional(3-D)deformations,the resolving accuracy is related with the measurement geometry constructed by these radars.This paper focuses on constrained geometry analysis to resolve 3-D deformations from three GB-rads.The geometric dilution of precision(GDOP)is utilized to evaluate 3-D deformation accuracy of a single target,and its theoretical equation is derived by building a simplified 3-D coordinate system.Then for a 3-D scene,its optimal accuracy problem is converted into determining the minimum value of an objective function with a boundary constraint.The genetic algorithm is utilized to solve this constrained optimization problem.Numerical simulations are made to validate the correctness of the theoretical analysis results.展开更多
The Chinese Meridian Project is a ground-based space environment monitoring network,which is constructed in two steps.The first step(Phase I)of the project consists of 15 observation stations located roughly along 120...The Chinese Meridian Project is a ground-based space environment monitoring network,which is constructed in two steps.The first step(Phase I)of the project consists of 15 observation stations located roughly along 120°E longitude and 30°N latitude.The second step(Phase II)of the project will additionally deploy 16 stations to better cover China’s territory,and build a stereo monitoring capability to monitor the cause and effect of the space weather chain in the solar terrestrial system.Based on the existing two monitoring chains in Phase I,two more chains will be established along 100°E longitude and 40°N latitude,respectively,forming a double-cross network configuration.After the two-step construction,the whole project will run nearly 300 instruments deployed at 31 stations.Aside from standard instruments,quite a few innovative and powerful instruments will be developed,such as radioheliographs with a very wide frequency band,a 3-station incoherent scattering radar to make a 3D measurement of the ionosphere,and a helium lidar to measure atmosphere density up to an altitude of 1000 km.展开更多
The Meridian Project is a ground- based network program to monitor solar-terrestrial space environment, which consists of a chain of ground-based observatories with multiple instruments including magnetometers, ionoso...The Meridian Project is a ground- based network program to monitor solar-terrestrial space environment, which consists of a chain of ground-based observatories with multiple instruments including magnetometers, ionosondes, HF and VHF radar, Lidar, IPS monitors, sounding rockets etc. The chain is mainly located in the neighborhood of 120°E meridian, and is thus named the Meridian Project. It has officially been approved by the Chinese government and will be finished by 2009. This talk will give an overview of the Meridian Project and the proposed International Space Weather Meridian Circle Program.展开更多
The Earth is buffered from the ferocious onslaught of the solar wind by a thin layer of matter known as the atmosphere and geospace.This layer absorbs energy from irradiance and outburst from the Sun,as well as from d...The Earth is buffered from the ferocious onslaught of the solar wind by a thin layer of matter known as the atmosphere and geospace.This layer absorbs energy from irradiance and outburst from the Sun,as well as from disasters,transient phenomena and anthropogenic emissions originated from Earth.Through complicated physics,the absorbed energy changes the atmospheric and geospace state and sometimes gets re-released to power extreme events such as space weather.Taking place globally,these complicated processes cannot be understood unless they are studied globally.The Chinese scientists have proposed the International Meridian Circle Program(IMCP)to meet this demand.By operating nearly 1000 instruments encompassing all latitudes along with the 120°E–60°W longitudes,IMCP aims,for the first time,to construct comprehensive 3D data representation of the atmosphere and geospace on a global scale and empower interdisciplinary research to tackle key questions related to Earth’s environment and climate change.展开更多
Ground-based interferometric synthetic aperture radar(GB-InSAR)can take deformation measurement with a high accuracy.Partition of the GB-InSAR deformation map benefits analyzing the deformation state of the monitoring...Ground-based interferometric synthetic aperture radar(GB-InSAR)can take deformation measurement with a high accuracy.Partition of the GB-InSAR deformation map benefits analyzing the deformation state of the monitoring scene better.Existing partition methods rely on labelled datasets or single deformation feature,and they cannot be effectively utilized in GBInSAR applications.This paper proposes an improved partition method of the GB-InSAR deformation map based on dynamic time warping(DTW)and k-means.The DTW similarities between a reference point and all the measurement points are calculated based on their time-series deformations.Then the DTW similarity and cumulative deformation are taken as two partition features.With the k-means algorithm and the score based on multi evaluation indexes,a deformation map can be partitioned into an appropriate number of classes.Experimental datasets of West Copper Mine are processed to validate the effectiveness of the proposed method,whose measurement points are divided into seven classes with a score of 0.3151.展开更多
Recent technological advances in cotton(Gossypium hirsutum L.) phenotyping have offered tools to improve the efficiency of data collection and analysis.High-throughput phenotyping(HTP) is a non-destructive and rapid a...Recent technological advances in cotton(Gossypium hirsutum L.) phenotyping have offered tools to improve the efficiency of data collection and analysis.High-throughput phenotyping(HTP) is a non-destructive and rapid approach of monitoring and measuring multiple phenotypic traits related to the growth,yield,and adaptation to biotic or abiotic stress.Researchers have conducted extensive experiments on HTP and developed techniques including spectral,fluorescence,thermal,and three-dimensional imaging to measure the morphological,physiological,and pathological resistance traits of cotton.In addition,ground-based and aerial-based platforms were also developed to aid in the implementation of these HTP systems.This review paper highlights the techniques and recent developments for HTP in cotton,reviews the potential applications according to morphological and physiological traits of cotton,and compares the advantages and limitations of these HTP systems when used in cotton cropping systems.Overall,the use of HTP has generated many opportunities to accurately and efficiently measure and analyze diverse traits of cotton.However,because of its relative novelty,HTP has some limitations that constrains the ability to take full advantage of what it can offer.These challenges need to be addressed to increase the accuracy and utility of HTP,which can be done by integrating analytical techniques for big data and continuous advances in imaging.展开更多
To develop an understanding of near-Earth space's response to solar activities and the coupling among different layers in geospace, China has initiated a ground base program to monitor China's geospace environ...To develop an understanding of near-Earth space's response to solar activities and the coupling among different layers in geospace, China has initiated a ground base program to monitor China's geospace environment called the Meridian Space Weather Monitoring Project(Chinese Meridian Project). The effort consists of a chain of 15 ground-based observatories located roughly along 120°E longitude and 30°N latitude. Each observatory is equipped with multiple instruments to measure key parameters such as the baseline and time-varying geomagnetic field, as well as the middle and upper atmosphere and ionosphere from about 20 to 1000 kilometers. This project started collecting data in 2012. We will give a brief introduction to the Chinese Meridian Project, and present recent scientific results mainly in ionospheric and atmospheric studies.展开更多
Microgravity science is an important branch of space science.Its major objective is to study the laws of materials movement in microgravity,as well as to reveal the influence of gravity on the movement of materials in...Microgravity science is an important branch of space science.Its major objective is to study the laws of materials movement in microgravity,as well as to reveal the influence of gravity on the movement of materials in different gravity environments.Application researches relevant to these basic studies are also important contents of microgravity science.The advanced subjects,to some extent,reflect the ability of human beings to understand nature and the R&D level in this field in various countries.In this paper,the recent progress and the latest achievements of microgravity science and application researches in China aboard space platforms such as the Core Capsule Tianhe of the China Space Station(CSS)and satellites,as well as utilizing ground-based short-term microgravity facilities such as the Drop Tower Beijing and TUFF,are summarized,which cover the following sub-disciplines:microgravity fluid physics,microgravity combustion science,space materials science,space fundamental physics,space bio-technology,and relevant space technology applications.展开更多
The Meridian Project is a ground-based network program to monitor solar-terrestrial space environment,which consists of a chain of 15 ground-based observatories located roughly along 120°E longitude and 30°N...The Meridian Project is a ground-based network program to monitor solar-terrestrial space environment,which consists of a chain of 15 ground-based observatories located roughly along 120°E longitude and 30°N latitude.The Meridian project started in 2008,and its construction was completed by 2011.The integration and test phase of the Meridian Project conducted in 2011 demonstrated its observation capabilities as expected.The project will be in full operation in 2012. This report gives an overview of the recent development and preliminary results of the Meridian Project since 2010.展开更多
The Chinese Meridian Project(CMP)is the Space Environment Ground Based Comprehensive Monitoring Network of China,a national major science and technology infrastructure project.The CMP consists of the Space Environment...The Chinese Meridian Project(CMP)is the Space Environment Ground Based Comprehensive Monitoring Network of China,a national major science and technology infrastructure project.The CMP consists of the Space Environment Monitoring System,Data Communication System,and Science Application System.Its construction has been divided into two steps:the PhaseⅠwas from 2008 to 2012;the PhaseⅡstarted at the end of 2019,expected to be completed at the end of 2023.Beyond 2023,the CMP as a whole will be in operation to make observations.This report introduces the construction progress of CMP PhaseⅡin the past two years,covering the construction progress of both the Data Communication System and the Science Application System.As for the Space Environment Monitoring System,this report mainly gives an introduction to the construction progress of large-scale advanced monitoring equipment,such as,the solar radio telescope,interplanetary scintillation telescope,incoherent scatter radar,high frequency radar,MST radar,and large-aperture Helium Lidar.In addition,this paper presents the construction plan for the next two years and the future outlook as well.展开更多
In order to realize the real-time and precise test for a weapon system of a certain type of fighter,a signal classification method according to attributes is proposed,common input channels for multiple signals are con...In order to realize the real-time and precise test for a weapon system of a certain type of fighter,a signal classification method according to attributes is proposed,common input channels for multiple signals are configured optimally,and a test adapter and an adaptive signal conditioning module is designed. The hardware of conditioning module can be configured flexibly and the programmable test range can be adjusted owing to programmable multiplexer. An FPGA adaptive filter is designed by the calculated filter coefficient vectors with LMS method to solve the problem of parallel test of fighter weapon system in electromagnetic interference environment. The adaptive signal conditioning technology is characterized by high efficiency,precision and integration. Its application makes the test system successful to conduct real-time and parallel test for a weapon system,which is developed based on VXI bus and virtual-instrument technology.展开更多
基金supported by the National Natural Science Foundation of China(61801007)the Beijing Natural Science Foundation(4194075)。
文摘Ground-based synthetic aperture radar(GB-SAR) has been successfully applied to the ground deformation monitoring.However, due to the short length of the GB-SAR platform, the scope of observation is largely limited. The practical applications drive us to make improvements on the conventional linear rail GB-SAR system in order to achieve larger field imaging. First, a turntable is utilized to support the rotational movement of the radar.Next, a series of high-squint scanning is performed with multiple squint angles. Further, the high squint modulation phase of the echo data is eliminated. Then, a new multi-angle imaging method is performed in the wave number domain to expand the field of view. Simulation and real experiments verify the effectiveness of this method.
基金supported by the National Key R&D Program of China (2018YFC1508502)the National Natural Science Foundation of China (41601569,61661043,61631011)the Science and Technology Innovation Guidance Project of Inner Mongolia Autonomous Region (2019GG139,KCBJ2017,KCBJ 2018014,2019ZD022)。
文摘In recent years, ground-based micro-deformation monitoring radar has attracted much attention due to its excellent monitoring capability. By controlling the repeated campaigns of the radar antenna on a fixed track, ground-based micro-deformation monitoring radar can accomplish repeat-pass interferometry without a space baseline and thus obtain highprecision deformation data of a large scene at one time. However, it is difficult to guarantee absolute stable installation position in every campaign. If the installation position is unstable, the stability of the radar track will be affected randomly, resulting in time-varying baseline error. In this study, a correction method for this error is developed by analyzing the error distribution law while the spatial baseline is unknown. In practice, the error data are first identified by frequency components, then the data of each one-dimensional array(in azimuth direction or range direction) are grouped based on numerical distribution period, and finally the error is corrected by the nonlinear model established with each group.This method is verified with measured data from a slope in southern China, and the results show that the method can effectively correct the time-varying baseline error caused by rail instability and effectively improve the monitoring data accuracy of groundbased micro-deformation radar in short term and long term.
基金supported by the National Natural Science Foundation of China(61960206009,61971037,31727901)the Natural Science Foundation of Chongqing+1 种基金China(2020jcyj-jq X0008)Chongqing Key Laboratory of Geological Environment Monitoring and Disaster Early-warning in Three Gorges Reservoir Area(ZD2020A0101)。
文摘When multiple ground-based radars(GB-rads)are utilized together to resolve three-dimensional(3-D)deformations,the resolving accuracy is related with the measurement geometry constructed by these radars.This paper focuses on constrained geometry analysis to resolve 3-D deformations from three GB-rads.The geometric dilution of precision(GDOP)is utilized to evaluate 3-D deformation accuracy of a single target,and its theoretical equation is derived by building a simplified 3-D coordinate system.Then for a 3-D scene,its optimal accuracy problem is converted into determining the minimum value of an objective function with a boundary constraint.The genetic algorithm is utilized to solve this constrained optimization problem.Numerical simulations are made to validate the correctness of the theoretical analysis results.
文摘The Chinese Meridian Project is a ground-based space environment monitoring network,which is constructed in two steps.The first step(Phase I)of the project consists of 15 observation stations located roughly along 120°E longitude and 30°N latitude.The second step(Phase II)of the project will additionally deploy 16 stations to better cover China’s territory,and build a stereo monitoring capability to monitor the cause and effect of the space weather chain in the solar terrestrial system.Based on the existing two monitoring chains in Phase I,two more chains will be established along 100°E longitude and 40°N latitude,respectively,forming a double-cross network configuration.After the two-step construction,the whole project will run nearly 300 instruments deployed at 31 stations.Aside from standard instruments,quite a few innovative and powerful instruments will be developed,such as radioheliographs with a very wide frequency band,a 3-station incoherent scattering radar to make a 3D measurement of the ionosphere,and a helium lidar to measure atmosphere density up to an altitude of 1000 km.
基金Supported by the National Natural Science Foundation of China (40325010, 40574068)
文摘The Meridian Project is a ground- based network program to monitor solar-terrestrial space environment, which consists of a chain of ground-based observatories with multiple instruments including magnetometers, ionosondes, HF and VHF radar, Lidar, IPS monitors, sounding rockets etc. The chain is mainly located in the neighborhood of 120°E meridian, and is thus named the Meridian Project. It has officially been approved by the Chinese government and will be finished by 2009. This talk will give an overview of the Meridian Project and the proposed International Space Weather Meridian Circle Program.
基金Supported by Beijing Municipal Science and Technology Commission(Z181100002918001)。
文摘The Earth is buffered from the ferocious onslaught of the solar wind by a thin layer of matter known as the atmosphere and geospace.This layer absorbs energy from irradiance and outburst from the Sun,as well as from disasters,transient phenomena and anthropogenic emissions originated from Earth.Through complicated physics,the absorbed energy changes the atmospheric and geospace state and sometimes gets re-released to power extreme events such as space weather.Taking place globally,these complicated processes cannot be understood unless they are studied globally.The Chinese scientists have proposed the International Meridian Circle Program(IMCP)to meet this demand.By operating nearly 1000 instruments encompassing all latitudes along with the 120°E–60°W longitudes,IMCP aims,for the first time,to construct comprehensive 3D data representation of the atmosphere and geospace on a global scale and empower interdisciplinary research to tackle key questions related to Earth’s environment and climate change.
基金supported by the National Natural Science Foundation of China(61971037,61960206009,61601031)the Natural Science Foundation of Chongqing,China(cstc2020jcyj-msxm X0608,cstc2020jcyj-jq X0008)。
文摘Ground-based interferometric synthetic aperture radar(GB-InSAR)can take deformation measurement with a high accuracy.Partition of the GB-InSAR deformation map benefits analyzing the deformation state of the monitoring scene better.Existing partition methods rely on labelled datasets or single deformation feature,and they cannot be effectively utilized in GBInSAR applications.This paper proposes an improved partition method of the GB-InSAR deformation map based on dynamic time warping(DTW)and k-means.The DTW similarities between a reference point and all the measurement points are calculated based on their time-series deformations.Then the DTW similarity and cumulative deformation are taken as two partition features.With the k-means algorithm and the score based on multi evaluation indexes,a deformation map can be partitioned into an appropriate number of classes.Experimental datasets of West Copper Mine are processed to validate the effectiveness of the proposed method,whose measurement points are divided into seven classes with a score of 0.3151.
文摘Recent technological advances in cotton(Gossypium hirsutum L.) phenotyping have offered tools to improve the efficiency of data collection and analysis.High-throughput phenotyping(HTP) is a non-destructive and rapid approach of monitoring and measuring multiple phenotypic traits related to the growth,yield,and adaptation to biotic or abiotic stress.Researchers have conducted extensive experiments on HTP and developed techniques including spectral,fluorescence,thermal,and three-dimensional imaging to measure the morphological,physiological,and pathological resistance traits of cotton.In addition,ground-based and aerial-based platforms were also developed to aid in the implementation of these HTP systems.This review paper highlights the techniques and recent developments for HTP in cotton,reviews the potential applications according to morphological and physiological traits of cotton,and compares the advantages and limitations of these HTP systems when used in cotton cropping systems.Overall,the use of HTP has generated many opportunities to accurately and efficiently measure and analyze diverse traits of cotton.However,because of its relative novelty,HTP has some limitations that constrains the ability to take full advantage of what it can offer.These challenges need to be addressed to increase the accuracy and utility of HTP,which can be done by integrating analytical techniques for big data and continuous advances in imaging.
基金Supported by the Chinese Meridian Projectthe Specialized Research Fund for State Key Laboratories of China
文摘To develop an understanding of near-Earth space's response to solar activities and the coupling among different layers in geospace, China has initiated a ground base program to monitor China's geospace environment called the Meridian Space Weather Monitoring Project(Chinese Meridian Project). The effort consists of a chain of 15 ground-based observatories located roughly along 120°E longitude and 30°N latitude. Each observatory is equipped with multiple instruments to measure key parameters such as the baseline and time-varying geomagnetic field, as well as the middle and upper atmosphere and ionosphere from about 20 to 1000 kilometers. This project started collecting data in 2012. We will give a brief introduction to the Chinese Meridian Project, and present recent scientific results mainly in ionospheric and atmospheric studies.
文摘Microgravity science is an important branch of space science.Its major objective is to study the laws of materials movement in microgravity,as well as to reveal the influence of gravity on the movement of materials in different gravity environments.Application researches relevant to these basic studies are also important contents of microgravity science.The advanced subjects,to some extent,reflect the ability of human beings to understand nature and the R&D level in this field in various countries.In this paper,the recent progress and the latest achievements of microgravity science and application researches in China aboard space platforms such as the Core Capsule Tianhe of the China Space Station(CSS)and satellites,as well as utilizing ground-based short-term microgravity facilities such as the Drop Tower Beijing and TUFF,are summarized,which cover the following sub-disciplines:microgravity fluid physics,microgravity combustion science,space materials science,space fundamental physics,space bio-technology,and relevant space technology applications.
基金Supported by National Basic Research Program of China(2012CB825602)
文摘The Meridian Project is a ground-based network program to monitor solar-terrestrial space environment,which consists of a chain of 15 ground-based observatories located roughly along 120°E longitude and 30°N latitude.The Meridian project started in 2008,and its construction was completed by 2011.The integration and test phase of the Meridian Project conducted in 2011 demonstrated its observation capabilities as expected.The project will be in full operation in 2012. This report gives an overview of the recent development and preliminary results of the Meridian Project since 2010.
文摘The Chinese Meridian Project(CMP)is the Space Environment Ground Based Comprehensive Monitoring Network of China,a national major science and technology infrastructure project.The CMP consists of the Space Environment Monitoring System,Data Communication System,and Science Application System.Its construction has been divided into two steps:the PhaseⅠwas from 2008 to 2012;the PhaseⅡstarted at the end of 2019,expected to be completed at the end of 2023.Beyond 2023,the CMP as a whole will be in operation to make observations.This report introduces the construction progress of CMP PhaseⅡin the past two years,covering the construction progress of both the Data Communication System and the Science Application System.As for the Space Environment Monitoring System,this report mainly gives an introduction to the construction progress of large-scale advanced monitoring equipment,such as,the solar radio telescope,interplanetary scintillation telescope,incoherent scatter radar,high frequency radar,MST radar,and large-aperture Helium Lidar.In addition,this paper presents the construction plan for the next two years and the future outlook as well.
基金Sponsored by the Key Equipment Research Project of Air Force of China (KJZ06119)
文摘In order to realize the real-time and precise test for a weapon system of a certain type of fighter,a signal classification method according to attributes is proposed,common input channels for multiple signals are configured optimally,and a test adapter and an adaptive signal conditioning module is designed. The hardware of conditioning module can be configured flexibly and the programmable test range can be adjusted owing to programmable multiplexer. An FPGA adaptive filter is designed by the calculated filter coefficient vectors with LMS method to solve the problem of parallel test of fighter weapon system in electromagnetic interference environment. The adaptive signal conditioning technology is characterized by high efficiency,precision and integration. Its application makes the test system successful to conduct real-time and parallel test for a weapon system,which is developed based on VXI bus and virtual-instrument technology.
