On Modeling and Pulse Phase Estimation of X-Ray Pulsars
On Modeling and Pulse Phase Estimation of X-Ray Pulsars
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DOI：
10.1109/tsp.2010.2050479
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发表时间：
2010-09
影响因子：
5.4
通讯作者：
A. A. Emadzadeh-A.;J. Speyer
中科院分区：
文献类型：
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作者：
A. A. Emadzadeh-A.;J. Speyer
建立了描述X射线脉冲星信号的数学模型，讨论了脉冲相位估计问题。给出了脉冲相位估计的Cramér-Rao下限。根据使用光子计数或直接使用测量的光子到达时间，提出并分析了两种不同的估计策略。在第一种方法中，利用历元折叠过程，在探测器上反演观测到的脉冲星速率函数，并通过将经验速率函数与已知脉冲星速率函数进行非线性最小二乘拟合来估计脉冲相位。结果表明，该估计是一致的，但不是渐近有效的。在第二种策略中，利用到达的光子时间的概率密度函数来描述最大似然(ML)估计问题。证明了最大似然估计是渐近有效的。文中还研究了所提出的估计器的计算复杂性。通过计算机仿真对分析结果进行了数值验证。
Mathematical models are developed to characterize the X-ray pulsar signals, and the pulse phase estimation problem is addressed. The Cramér-Rao lower bound for estimation of the pulse phase is presented. Depending on employing the photon counts or direct use of the measured photon time of arrivals, two different estimation strategies are proposed and analyzed. In the first approach, utilizing the epoch folding procedure, the observed pulsar rate function on the detector is retrieved, and the pulse phase is estimated through a nonlinear least-squares fit of the empirical rate function to the known pulsar rate function. It is shown that this estimator is consistent, but not asymptotically efficient. In the second strategy, a maximum likelihood (ML) estimation problem is formulated using the probability density function of the photon time of arrivals. It is shown that the ML estimator is asymptotically efficient. Computational complexity of the proposed estimators is investigated as well. The analytical results are verified numerically via computer simulations.