The basic principle of pulsar timing model was introduced, and the general relativistic corrections were analyzed when pulse time of arrival (TOA) was transferred to coordinate TOA at the Solar System Barycentre. Base...The basic principle of pulsar timing model was introduced, and the general relativistic corrections were analyzed when pulse time of arrival (TOA) was transferred to coordinate TOA at the Solar System Barycentre. Based on the shifting, an iterative method of autonomous position determination for spacecraft was developed. Accordingly, the linear form of the position offset equation was evolved. Using the initial estimated value of spacecraft’s position as the input of pulsar timing equation, through calculation of the offset between measured or transferred and predicted TOA, the position offset can be solved by Least Squares. At last, the main error sources including modeling error and parameters error were discussed.展开更多
天文学计算通常具有数据量大、计算量多的特点.平方公里阵列射电望远镜(Square Kilometre Array,SKA)等装置的建设和高性能计算平台的发展促进了天文学与高性能计算之间的联系.脉冲星搜索是SKA的主要科学方向之一.本文介绍了一种基于Ope...天文学计算通常具有数据量大、计算量多的特点.平方公里阵列射电望远镜(Square Kilometre Array,SKA)等装置的建设和高性能计算平台的发展促进了天文学与高性能计算之间的联系.脉冲星搜索是SKA的主要科学方向之一.本文介绍了一种基于OpenMP多线程和Multiprocessing多进程技术加速脉冲星搜索管线的方案,提出了一种解决负载不平衡问题的方法,并成功地将优化后的管线安装于中国SKA区域中心原型机的x86和ARM计算节点.在默奇森大视场阵列望远镜(Murchison Widefield Array,MWA)的3个脉冲星搜索样例上的测试显示,与原始单核心管线相比,优化后的管线在x86和ARM节点上分别获得10.4–12.2倍和24.5–25.8倍的加速,并行效率达到37.1%–43.6%和24.5%–26.9%.并且ARM节点比x86节点的计算快1.1–1.3倍,显示出国产计算设备在SKA数据处理方面的巨大潜力.这项应用优化成果,近期将用于加速MWA南天快速两米巡天(Southern-sky MWA Rapid Two-metre,SMART)项目的脉冲星搜寻工作.展开更多
Due to high stable rotations, timing of pulsars provides a natural tool to correct the frequency deviation of spaceborne atomic clocks. Based on processing the observational data about a year of Crab pulsar given by X...Due to high stable rotations, timing of pulsars provides a natural tool to correct the frequency deviation of spaceborne atomic clocks. Based on processing the observational data about a year of Crab pulsar given by XPNAV-1 satellite, we study the possibility of correcting the frequency deviation of spaceborne atomic clocks using pulsar timing. According to the observational data in X-ray band and the timing model parameters from radio observations, the pre-fit timing residuals with a level of 67.66 μs are obtained. By fitting the slope of the timing residuals affected by the faked frequency-biased reference clock, we estimated successfully the relative frequency deviation of the reference clock. For a satellite clock with frequency deviation of the order about 10^(-12), a calibration accuracy with relative error of about 2% can be obtained from the Crab pulsar’s data for one year.The stability of the time scale based on Crab pulsar is about 10^(-12) for an interval of one year.展开更多
脉冲星在天体演化、物理学、计时、深空自主导航、引力波探测等领域均有重要的学术和应用价值,脉冲星搜寻及其应用也成为了当前天文界热点研究之一。为了更好地探究脉冲星搜寻及其应用领域的研究现状和未来发展趋势,在Web of Science(W...脉冲星在天体演化、物理学、计时、深空自主导航、引力波探测等领域均有重要的学术和应用价值,脉冲星搜寻及其应用也成为了当前天文界热点研究之一。为了更好地探究脉冲星搜寻及其应用领域的研究现状和未来发展趋势,在Web of Science(WOS)数据库筛选出有关脉冲星搜寻及应用的964篇文献,在阅读核心文献的基础上,采用数据分析和可视化方法进行深入探讨。结果表明,脉冲星搜寻及应用领域的研究经历了初始探索阶段和稳健发展阶段,目前进入蓬勃增长阶段。该领域各国之间密切合作,形成了三大主要的研究群体。脉冲星搜寻及其应用研究在未来将产生如直接探测引力波、深空自主导航等重要科研价值和实际应用结果,将进一步丰富和多元化脉冲星的研究领域。展开更多
In order to improve the autonomous navigation capability of satellite,a pulsar/CNS（celestial navigation system） integrated navigation method based on federated unscented Kalman filter（UKF） is proposed.The celestia...In order to improve the autonomous navigation capability of satellite,a pulsar/CNS（celestial navigation system） integrated navigation method based on federated unscented Kalman filter（UKF） is proposed.The celestial navigation is a mature and stable navigation method.However,its position determination performance is not satisfied due to the low accuracy of horizon sensor.Single pulsar navigation is a new navigation method,which can provide highly accurate range measurements.The major drawback of single pulsar navigation is that the system is completely unobservable.As two methods are complementary to each other,the federated UKF is used here for fusing the navigation data from single pulsar navigation and CNS.Compared to the traditional celestial navigation method and single pulsar navigation,the integrated navigation method can provide better navigation performance.The simulation results demonstrate the feasibility and effectiveness of the navigation method.展开更多
We report the results of a search for radio pulsars in five supernova remnants(SNRs)with the FAST telescope.The observations were made using the 19-beam receiver in“snapshot”mode.The integration time for each pointi...We report the results of a search for radio pulsars in five supernova remnants(SNRs)with the FAST telescope.The observations were made using the 19-beam receiver in“snapshot”mode.The integration time for each pointing was 10 min.We discovered a new pulsar,PSR J1845–0306,which has a spin period of 983.6 ms and a dispersion measure of 444.6±2.0 cm^(−3)·pc,in observations of SNR G29.6+0.1.To judge the association between the pulsar and the SNR,further verification is needed.We also re-detected some known pulsars in the data from SNRs G29.6+0.1 and G29.7–0.3.No pulsars were detected in the observations of the other three SNRs.展开更多
基金Supported by the National Defence Laboratory Foundation of China (Grant No. 9140C3601010901) Science Foundation of Shaanxi Province (Grant No. 2007F12)+1 种基金the Technology Specialism Foundation of Shaanxi Education Depart-ment of Shaanxi Province (Grant No. 07JK332)the Innovative Research Plan of Xi’an University of Technology (Grant No. 105-210714)
文摘The basic principle of pulsar timing model was introduced, and the general relativistic corrections were analyzed when pulse time of arrival (TOA) was transferred to coordinate TOA at the Solar System Barycentre. Based on the shifting, an iterative method of autonomous position determination for spacecraft was developed. Accordingly, the linear form of the position offset equation was evolved. Using the initial estimated value of spacecraft’s position as the input of pulsar timing equation, through calculation of the offset between measured or transferred and predicted TOA, the position offset can be solved by Least Squares. At last, the main error sources including modeling error and parameters error were discussed.
文摘天文学计算通常具有数据量大、计算量多的特点.平方公里阵列射电望远镜(Square Kilometre Array,SKA)等装置的建设和高性能计算平台的发展促进了天文学与高性能计算之间的联系.脉冲星搜索是SKA的主要科学方向之一.本文介绍了一种基于OpenMP多线程和Multiprocessing多进程技术加速脉冲星搜索管线的方案,提出了一种解决负载不平衡问题的方法,并成功地将优化后的管线安装于中国SKA区域中心原型机的x86和ARM计算节点.在默奇森大视场阵列望远镜(Murchison Widefield Array,MWA)的3个脉冲星搜索样例上的测试显示,与原始单核心管线相比,优化后的管线在x86和ARM节点上分别获得10.4–12.2倍和24.5–25.8倍的加速,并行效率达到37.1%–43.6%和24.5%–26.9%.并且ARM节点比x86节点的计算快1.1–1.3倍,显示出国产计算设备在SKA数据处理方面的巨大潜力.这项应用优化成果,近期将用于加速MWA南天快速两米巡天(Southern-sky MWA Rapid Two-metre,SMART)项目的脉冲星搜寻工作.
基金supported by the National SKA Program of China(No.2020SKA0120103)the National Natural Science Foundation of China(Nos.U1831130 and U1531112).
文摘Due to high stable rotations, timing of pulsars provides a natural tool to correct the frequency deviation of spaceborne atomic clocks. Based on processing the observational data about a year of Crab pulsar given by XPNAV-1 satellite, we study the possibility of correcting the frequency deviation of spaceborne atomic clocks using pulsar timing. According to the observational data in X-ray band and the timing model parameters from radio observations, the pre-fit timing residuals with a level of 67.66 μs are obtained. By fitting the slope of the timing residuals affected by the faked frequency-biased reference clock, we estimated successfully the relative frequency deviation of the reference clock. For a satellite clock with frequency deviation of the order about 10^(-12), a calibration accuracy with relative error of about 2% can be obtained from the Crab pulsar’s data for one year.The stability of the time scale based on Crab pulsar is about 10^(-12) for an interval of one year.
文摘脉冲星在天体演化、物理学、计时、深空自主导航、引力波探测等领域均有重要的学术和应用价值,脉冲星搜寻及其应用也成为了当前天文界热点研究之一。为了更好地探究脉冲星搜寻及其应用领域的研究现状和未来发展趋势,在Web of Science(WOS)数据库筛选出有关脉冲星搜寻及应用的964篇文献,在阅读核心文献的基础上,采用数据分析和可视化方法进行深入探讨。结果表明,脉冲星搜寻及应用领域的研究经历了初始探索阶段和稳健发展阶段,目前进入蓬勃增长阶段。该领域各国之间密切合作,形成了三大主要的研究群体。脉冲星搜寻及其应用研究在未来将产生如直接探测引力波、深空自主导航等重要科研价值和实际应用结果,将进一步丰富和多元化脉冲星的研究领域。
基金supported by the National High Technology Research and Development Program of China(2006AAJ109)Aviation Science Fund(20070818001)
文摘In order to improve the autonomous navigation capability of satellite,a pulsar/CNS（celestial navigation system） integrated navigation method based on federated unscented Kalman filter（UKF） is proposed.The celestial navigation is a mature and stable navigation method.However,its position determination performance is not satisfied due to the low accuracy of horizon sensor.Single pulsar navigation is a new navigation method,which can provide highly accurate range measurements.The major drawback of single pulsar navigation is that the system is completely unobservable.As two methods are complementary to each other,the federated UKF is used here for fusing the navigation data from single pulsar navigation and CNS.Compared to the traditional celestial navigation method and single pulsar navigation,the integrated navigation method can provide better navigation performance.The simulation results demonstrate the feasibility and effectiveness of the navigation method.
基金supported by the National SKA Program of China (Grant No. 2020SKA0120200)the National Natural Science Foundation of China (Grant Nos. 12041303, 12273100, 12041304, and 12288102)+5 种基金the National Key R&D Program of China (Grant No. 2022YFC2205201)the West Light Foundation of the Chinese Academy of Sciences (Grant No. WLFC 2021-XBQNXZ-027)the Major Science and Technology Program of Xinjiang Uygur Autonomous Region (Grant No. 2022A03013-4)the Natural Science Foundation of Xinjiiang Uygur Autonomous Region (Grant No. 2022D01D85)the open program of the Key Laboratory of Xinjiang Uygur Autonomous Region (Grant No. 2020D04049)partly supported by the Operation, Maintenance and Upgrading Fund for Astronomical Telescopes and Facility Instruments, budgeted from the Ministry of Finance of China and administrated by the CAS
文摘We report the results of a search for radio pulsars in five supernova remnants(SNRs)with the FAST telescope.The observations were made using the 19-beam receiver in“snapshot”mode.The integration time for each pointing was 10 min.We discovered a new pulsar,PSR J1845–0306,which has a spin period of 983.6 ms and a dispersion measure of 444.6±2.0 cm^(−3)·pc,in observations of SNR G29.6+0.1.To judge the association between the pulsar and the SNR,further verification is needed.We also re-detected some known pulsars in the data from SNRs G29.6+0.1 and G29.7–0.3.No pulsars were detected in the observations of the other three SNRs.
