Angles-only relative orbit determination for space non-cooperative targets based on passive sensor is subject to weakly observable problem of the relative state between two spacecraft. Previously, the evidence for ang...Angles-only relative orbit determination for space non-cooperative targets based on passive sensor is subject to weakly observable problem of the relative state between two spacecraft. Previously, the evidence for angles-only observability was found by using cylindrical dynamics, however, the solution of orbit determination is still not provided. This study develops a relative orbit determination algorithm with the cylindrical dynamics based on differential evolution. Firstly, the relative motion dynamics and line-of-sight measurement model for nearcircular orbit are established in cylindrical coordinate system.Secondly, the observability is qualitatively analyzed by using the dynamics and measurement model where the unobservable geometry is found. Then, the angles-only relative orbit determination problem is modeled into an optimal searching frame and an improved differential evolution algorithm is introduced to solve the problem. Finally, the proposed algorithm is verified and tested by a set of numerical simulations in the context of highEarth and low-Earth cases. The results show that initial relative orbit determination(IROD) solution with an appropriate accuracy in a relative short span is achieved, which can be used to initialize the navigation filter.展开更多
This work introduces a novel method for measuring thin film thickness,employing a multi-wavelength method that significantly reduces the need for broad-spectrum data.Unlike traditional techniques that require sev⁃eral...This work introduces a novel method for measuring thin film thickness,employing a multi-wavelength method that significantly reduces the need for broad-spectrum data.Unlike traditional techniques that require sev⁃eral hundred spectral data points,the multi-wavelength method achieves precise thickness measurements with data from only 10 wavelengths.This innovation not only simplifies the process of spectral measurement analysis but also enables accurate real-time thickness measurement on industrial coating production lines.The method effectively reconstructs and fits the visible spectrum(400-800 nm)using a minimal amount of data,while maintaining measurement error within 7.1%.This advancement lays the foundation for more practical and efficient thin film thickness determination techniques in various industrial applications.展开更多
以“嫦娥六号”任务搭载的巴基斯坦立方星为研究对象,系统分析了其轨道特性、力学环境及测量手段,重点探讨了影响轨道变化的主要摄动因素。在缺乏测距和甚长基线干涉测量(Very Long Baseline Interferometry,VLBI)支持的条件下,提出了...以“嫦娥六号”任务搭载的巴基斯坦立方星为研究对象,系统分析了其轨道特性、力学环境及测量手段,重点探讨了影响轨道变化的主要摄动因素。在缺乏测距和甚长基线干涉测量(Very Long Baseline Interferometry,VLBI)支持的条件下,提出了一种基于三向测速的轨道确定方法,建立了三向测速模型,并对测速误差进行分析;同时,设计了适用于稀疏观测模式的定轨策略,并完成了误差评估。此外,对立方星轨道的长期演化进行了深入分析。研究结果表明:三向多普勒测速残差的均方根误差为2 mm/s,轨道确定的位置精度优于1 km;立方星轨道主要受月球非球形引力摄动和地球质点引力摄动的影响,三体引力在其轨道演化中起到了重要作用。轨道演化预测显示,立方星的近月距离预计于2025年4月缩小至小于月球半径。研究为深空探测任务中的微小卫星轨道确定与演化分析提供了参考。展开更多
锻炼行为促进是公共卫生领域的关键议题,但现有理论在预测和干预锻炼行为时仍存在局限性。基于锻炼行为发生的必要条件,提出了锻炼行为的MTMSP(motor competence,time,motivation,self-control and physical exertion,运动能力、时间、...锻炼行为促进是公共卫生领域的关键议题,但现有理论在预测和干预锻炼行为时仍存在局限性。基于锻炼行为发生的必要条件,提出了锻炼行为的MTMSP(motor competence,time,motivation,self-control and physical exertion,运动能力、时间、动机、自我控制和体力消耗)决定因素模型(以下简称“MTMSP决定因素模型”)。该模型从个体层面深入解析锻炼行为的发生机制,将运动能力、时间、动机、自我控制和体力消耗作为核心决定因素,并通过“前提条件-双过程动机-自我控制调节”三级结构揭示各因素的内在关联。研究认为,MTMSP决定因素模型为克服锻炼意向−行为差距和维持问题提供了新的理论视角。未来研究可基于该模型,诊断目标人群的初始状态,设计更具针对性的干预方案,促进锻炼行为的发生。展开更多
基金supported by the National Natural Science Foundation of China (12272168)the Foundation of Science and Technology on Space Intelligent Control Laboratory (HTKJ2023KL502015)。
文摘Angles-only relative orbit determination for space non-cooperative targets based on passive sensor is subject to weakly observable problem of the relative state between two spacecraft. Previously, the evidence for angles-only observability was found by using cylindrical dynamics, however, the solution of orbit determination is still not provided. This study develops a relative orbit determination algorithm with the cylindrical dynamics based on differential evolution. Firstly, the relative motion dynamics and line-of-sight measurement model for nearcircular orbit are established in cylindrical coordinate system.Secondly, the observability is qualitatively analyzed by using the dynamics and measurement model where the unobservable geometry is found. Then, the angles-only relative orbit determination problem is modeled into an optimal searching frame and an improved differential evolution algorithm is introduced to solve the problem. Finally, the proposed algorithm is verified and tested by a set of numerical simulations in the context of highEarth and low-Earth cases. The results show that initial relative orbit determination(IROD) solution with an appropriate accuracy in a relative short span is achieved, which can be used to initialize the navigation filter.
基金Supported by National Key R&D Program of China(2021YFA0715500)National Natural Science Foundation of China(NSFC)(12227901)+2 种基金Strategic Priority Research Program(B)of the Chinese Academy of Sciences(XDB0580000)Shanghai Municipal Science and Technology Major Project(2019SHZDZX01)Chinese Academy of Sciences President's International Fellowship Initiative(2021PT0007).
文摘This work introduces a novel method for measuring thin film thickness,employing a multi-wavelength method that significantly reduces the need for broad-spectrum data.Unlike traditional techniques that require sev⁃eral hundred spectral data points,the multi-wavelength method achieves precise thickness measurements with data from only 10 wavelengths.This innovation not only simplifies the process of spectral measurement analysis but also enables accurate real-time thickness measurement on industrial coating production lines.The method effectively reconstructs and fits the visible spectrum(400-800 nm)using a minimal amount of data,while maintaining measurement error within 7.1%.This advancement lays the foundation for more practical and efficient thin film thickness determination techniques in various industrial applications.
文摘锻炼行为促进是公共卫生领域的关键议题,但现有理论在预测和干预锻炼行为时仍存在局限性。基于锻炼行为发生的必要条件,提出了锻炼行为的MTMSP(motor competence,time,motivation,self-control and physical exertion,运动能力、时间、动机、自我控制和体力消耗)决定因素模型(以下简称“MTMSP决定因素模型”)。该模型从个体层面深入解析锻炼行为的发生机制,将运动能力、时间、动机、自我控制和体力消耗作为核心决定因素,并通过“前提条件-双过程动机-自我控制调节”三级结构揭示各因素的内在关联。研究认为,MTMSP决定因素模型为克服锻炼意向−行为差距和维持问题提供了新的理论视角。未来研究可基于该模型,诊断目标人群的初始状态,设计更具针对性的干预方案,促进锻炼行为的发生。
