小波域中的维纳滤波在综合脉冲星时算法中的应用

脉冲星自转非常稳定，可用作时间标准. 然而由单脉冲星定义的脉冲星时受多种噪声源的影响，其频率稳定度还不够好，因此可采取对多颗脉冲星定义的脉冲星时进行综合的方法来削弱各噪声源的影响，以提高脉冲星时的稳定度. 不同的脉冲星有着各自不同的自转频率，在不同频率段所受噪声的影响也不同，应用小波分析的方法对脉冲星时做综合，可以兼顾脉冲星时的长期与短期稳定度，在不同的频率范围取不同的权值以达到更好的结果；脉冲星的计时残差是由计时参考的原子时的误差和脉冲星计时误差两部分引起的，用维纳滤波的方法可以将两者分开，并主要以消除掉参考钟误差后的残差为计时残差实现对脉冲星计时的综合. 在这两种方法的基础上，提出一种基于小波域中的维纳滤波方法，利用小波独有的特性和维纳滤波最小误差估计的优点，更有效地消除噪声对脉冲星时的影响. 实验结果表明，该方法可以有效降低脉冲星计时残差中的噪声影响.

Use of wiener filtration in wavelet domain in ensemble pulsar time algorithm

Pulsars rotate extremely stably, they can be used as time standard. However, pulsar time defined by single pulsar is influenced by several noise resources. To weaken these influences to get a more stable time scale, one can take ensemble analysis to obtain the ensemble pulsar time. Since different pulsars have different rotation frequency, and the noise source have different influence on different frequency of each pulsar, we can apply wavelet analysis to integrate the pulsar time, and this algorithm can take consideration of the long-term and short-term stability of pulsar time. On the other hand, the pulsar timing residuals are caused by reference atomic clock and pulsar itself, so we can apply Wiener filtration analysis-to distinguish the two parts, and then calculate the ensemble pulsar time with the residuals after removing the error of reference atomic clock. Based on both of the two algorithms, a new algorithm of Wiener filtration in wavelet domain has been presented, which combines the merits of wavelet analysis and Wiener filtration and can remove the noise influence to pulsar time more effectively. Experimental results prove that Wiener filtration in wavelet domain can reduce noise influence of pulsar timing residuals effectively.