X射线脉冲星脉冲到达航天器时间测量

X射线脉冲星脉冲到达时间(TOA)的空间测量是航天器自主导航和用脉冲星钟作航天器时间标准的基础.在简要介绍地面射电观测TOA测量方法基础上,重点研究了X射线脉冲星脉冲到达时间的空间测量方法和算法.讨论了利用X射线脉冲星辐射光子到达时间观测,建立X射线脉冲轮廓的方法;给出了通过观测得到的X射线脉冲轮廓与标准脉冲轮廓比较,精确确定TOA的测量方法和实用算法.讨论了削弱多普勒效应对TOA测量影响的方法.

Determination of X Ray Pulsar Pulse Time of Arrival at Spacecraft

X ray pulsar can be used for spacecraft autonomous navigation.Pulsar clock can be used to stabilize onboard clock.Utilization in space of X ray pulsar clock is based on high precision determination of pulsar pulse Time of Arrival(TOA)at spacecraft.A method to obtain X ray pulsar pulse profile with individual photon arrival time records by onboard X ray detect system was discussed.In the case that an onboard clock is used as time reference for X ray pulsar timing recorded individual photon arrival time(spacecraft proper time)should be converted to barycentric dynamic time(TDB).Doppler effect due to orbit velocity of spacecraft during observation period may blur observed pulse profile.To mitigate smearing effect to pulse profile further transformation of recorded photon arrival time to Solar System Barycenter(SSB)is required using estimated approximate spacecraft position by spacecraft dynamics.Then obtained X ray pulsar pulse profile is compared with its standard template pulse profile to derive an observed pulse arrival time.Algorithm of determining X ray pulsar TOA at spacecraft with high precision was reviewed.Detailed analysis method to determine TOA in Fourier frequency domain was introduced and compared to analysis method in time domain.