一种新的脉冲星累积脉冲轮廓时间延迟测量算法

A New Time Delay Measurement Algorithm for Pulsar Accumulated Pulse Profile

为提高X射线脉冲星导航系统中累积脉冲轮廓的时间延迟测量精度,分析了X射线脉冲星累积脉冲轮廓的特点和现有时延测量算法的缺陷,提出了一种粗略估计和精确测量相结合的时间延迟测量算法。该算法首先利用三阶互小波累积量进行粗略估计,可抑制尺度伸缩和噪声的影响;然后通过抛物面内插法精确测量时间延迟,避免了小步长的迭代运算,可大幅度降低算法的运算量。利用美国罗希(Rossi)X射线时变探测卫星的实测脉冲星数据进行实验,结果表明:该算法可屏蔽由多普勒效应和相位间隔长度的不同引起的尺度伸缩,能够抑制噪声,测量误差小于现有算法;当相位间隔为0.9°时,该算法的测量精度达到最高;该算法运算量小,不足现有算法的10%,适用于X射线脉冲星导航系统。

In order to improve the time delay measurement accuracy of pulsar accumulated pulse profile in X-ray pulsar-based navigation（XPNAV） system,the features of X-ray pulsar accumulated pulse profile are studied,defects of other existing algorithms are analyzed,and then a new algorithm combining rough estimation with accurate precise measurement is proposed in this paper.In the rough estimation,the effects of scale stretch and noise are suppressed by 3rd-order wavelant.A parabolic interpolation method is used in the accurate measurement,the iterative operation with small step length is avoided,and the computation of the algorithm is significantly reduced.The experiments are carried out by using the pulsar data observed by Rossi X-ray Timing Explorer,and the results show that this algorithm can suppress effects of the scale stretch and noise effectively and the measurement error is smaller than the other existing algorithms;this algorithm achieves the highest measurement accuracy when the phase bin is 0.9 degrees;the computation time of this algorithm is less than 10 percent of that of Taylor FFT algorithm,and is suitable for XPNAV.