针对当前利用大地水准面模型求解垂线偏差精度不高、稳健性差的问题,设计了一种严密的垂线偏差抗差最小二乘解法.首先,基于大地水准面与垂线偏差的关系,采用EGM2008(Earth Gravity Model 2008)重力场模型计算参数初始解;然后,引入中位...针对当前利用大地水准面模型求解垂线偏差精度不高、稳健性差的问题,设计了一种严密的垂线偏差抗差最小二乘解法.首先,基于大地水准面与垂线偏差的关系,采用EGM2008(Earth Gravity Model 2008)重力场模型计算参数初始解;然后,引入中位数抗差法,并选用Huber权函数计算等价权,迭代计算出稳健的垂线偏差最小二乘解;最后,结合两个实测算例对设计方法进行验证.试验结果表明,该方法计算的垂线偏差分量与约定真值最大偏差在0:5′′左右,相较于对比方法精度更高;同时,该方法能有效抵抗粗差值的影响,具有较强的稳健性.展开更多
Gamma-ray polarimetry is a new and prospective tool for studying extremely high-energy celestial objects and is of great significance for the field of astrophysics.With the rapid development of microsatellite technolo...Gamma-ray polarimetry is a new and prospective tool for studying extremely high-energy celestial objects and is of great significance for the field of astrophysics.With the rapid development of microsatellite technology,the advantages of space exploration have become increasingly apparent.Therefore,we simulated a soft-gamma-ray polarimeter for a microsatellite based on the Compton scattering principle.We performed detailed Monte Carlo simulations using monoenergetic gamma-ray linear-polarization sources and Crab-like sources in the energy range of 0.1-10 MeV considering the orbital background.The polarimeter exhibited excellent polarization detection performance.The modulation factor was 0.80±0.01,and the polarization angles were accurate within an error of 0.2°at 200 keV for on-axis incidence.For the Crab-like sources for on-axis incidence,the polarization degrees were consistent with the set values within the error tolerance,the modulation factor was 0.76±0.01,and the minimum detectable polarization reached 2.4%at 3σfor an observation time of10^(6) s.Additionally,the polarimeter exhibited recoil electron tracking,imaging,and powerful background suppression in a large field of view(FoV;∼2πsr).The proposed polarimeter meets the requirements of a space soft-gamma-ray polarization detector and has promising research prospects.展开更多
中国科学院云南天文台首次提出了太阳爆发过程及相应磁场结构抵近探测的科学项目,该项目将对太阳大气及发生在其中的剧烈活动进行前所未有的近距离测量。为项目研制的探测器近日区域运行时间将超过帕克太阳探测器(Parker Solar Probe,P...中国科学院云南天文台首次提出了太阳爆发过程及相应磁场结构抵近探测的科学项目,该项目将对太阳大气及发生在其中的剧烈活动进行前所未有的近距离测量。为项目研制的探测器近日区域运行时间将超过帕克太阳探测器(Parker Solar Probe,PSP)和太阳轨道探测器(Solar Orbiter),其热防护系统遇到的困难也远超后两者。首先分析了抵近探测器的轨道环境特点,提出了热防护的设计思路,然后给出了具体热防护系统设计、仿真和地面实验方案。初步研究显示,热防护系统的设计方案具有辐射散热好、耐高温、稳定可靠等优点。展开更多
文摘针对当前利用大地水准面模型求解垂线偏差精度不高、稳健性差的问题,设计了一种严密的垂线偏差抗差最小二乘解法.首先,基于大地水准面与垂线偏差的关系,采用EGM2008(Earth Gravity Model 2008)重力场模型计算参数初始解;然后,引入中位数抗差法,并选用Huber权函数计算等价权,迭代计算出稳健的垂线偏差最小二乘解;最后,结合两个实测算例对设计方法进行验证.试验结果表明,该方法计算的垂线偏差分量与约定真值最大偏差在0:5′′左右,相较于对比方法精度更高;同时,该方法能有效抵抗粗差值的影响,具有较强的稳健性.
基金This work was supported by the National Natural Science Foundation of China(Nos.U2031206,12273086,12133007)the CAS Key Technology Talent Program。
文摘Gamma-ray polarimetry is a new and prospective tool for studying extremely high-energy celestial objects and is of great significance for the field of astrophysics.With the rapid development of microsatellite technology,the advantages of space exploration have become increasingly apparent.Therefore,we simulated a soft-gamma-ray polarimeter for a microsatellite based on the Compton scattering principle.We performed detailed Monte Carlo simulations using monoenergetic gamma-ray linear-polarization sources and Crab-like sources in the energy range of 0.1-10 MeV considering the orbital background.The polarimeter exhibited excellent polarization detection performance.The modulation factor was 0.80±0.01,and the polarization angles were accurate within an error of 0.2°at 200 keV for on-axis incidence.For the Crab-like sources for on-axis incidence,the polarization degrees were consistent with the set values within the error tolerance,the modulation factor was 0.76±0.01,and the minimum detectable polarization reached 2.4%at 3σfor an observation time of10^(6) s.Additionally,the polarimeter exhibited recoil electron tracking,imaging,and powerful background suppression in a large field of view(FoV;∼2πsr).The proposed polarimeter meets the requirements of a space soft-gamma-ray polarization detector and has promising research prospects.
文摘中国科学院云南天文台首次提出了太阳爆发过程及相应磁场结构抵近探测的科学项目,该项目将对太阳大气及发生在其中的剧烈活动进行前所未有的近距离测量。为项目研制的探测器近日区域运行时间将超过帕克太阳探测器(Parker Solar Probe,PSP)和太阳轨道探测器(Solar Orbiter),其热防护系统遇到的困难也远超后两者。首先分析了抵近探测器的轨道环境特点,提出了热防护的设计思路,然后给出了具体热防护系统设计、仿真和地面实验方案。初步研究显示,热防护系统的设计方案具有辐射散热好、耐高温、稳定可靠等优点。
