基于TOA信息的脉冲星信号周期估计方法

针对脉冲星信号周期估计需逐步搜索、计算量大等问题,提出脉冲星信号周期直接估计算法.根据周期不确定误差对时域上脉冲到达时间(Pulse Time of Arrival,TOA)估计方法的影响,推导了基于TOA信息的脉冲星信号周期估计方法的数学模型.该方法将一组观测到的脉冲光子到达时间序列(Photon Time of Arrivals,TOAs)进行等时间间隔分段,在时域上对每段TOAs进行相位估计获得相应的TOA信息,并根据建立的TOA信息与周期误差的关系采用最小二乘原理估计脉冲星信号周期.对周期准确性的评价不同于传统的依赖折叠轮廓的好坏,而是以TOA与时间图像的斜率作为依据,这一依据更直观、易于理解.理论分析与物理、计算机仿真数据结果表明,本文所提的周期估计方法能够根据短时间脉冲光子到达时间序列获得高精度和高分辨率的脉冲信号周期,有利于X射线脉冲星导航的工程应用.

Pulse Period Estimation Method Based on TOA Information

Aiming at the problem of huge computation in pulsar period estimation methods,a direct pulsar period estimation algorithm was proposed.Based on the discussion of the influence of period errors on pulse time of arrival estimation methods,the mathematical model of the said period estimation method using TOA information is derived.In this method,a set of photon time of arrivals(TOAs) is divided into several segments in an equal time interval,and TOA information corresponding to each segment is calculated using time domain methods.According to the formula of the TOA information and period error,the Least Square method is adopted to estimate the period.A new intuitionistic criterion for the precision of pulsar period is developed by the value of the slope of the (φ)-t graph,which is different from the scheme that searches the perfect period based on maximum peak principle.Theoretical analysis and the results of experiments utilizing physical and numerical data are demonstrated that the presented pulsar period estimation method can achieve a precise and high-resolution period from a short observation of photon time of arrivals,which can help to realize the engineering application of X-ray pulsar navigation.