基于循环平稳信号相干统计量的脉冲星周期估计新方法

Period estimation method for weak pulsars based on coherent statistic of cyclostationary signal

讨论了脉冲星的周期估计在脉冲星搜索中的重要性.将脉冲星观测信号建模为二阶循环平稳模型,仿真验证了其合理性.在此基础上,提出了一种基于双谱相干统计量的周期估计新方法,并给出了稳健有效的周期搜索策略以消除其对数据量的敏感性.分别对单脉冲脉冲星(PSRJ0437-4715)的实测信号和双脉冲脉冲星(PSRB1821-24)的仿真信号进行了周期估计,实验表明,相比较于常用的傅里叶频谱法,该时域方法直观、有效,在低信噪比情况下仍具有很好的性能,且适用于非连续观测数据.尽管方法运算量较大,但仍然可为微弱脉冲星的周期估计提供有力参考.

The importance of period estimation for pulsars in pulsar searching was discussed.In the paper,the radiation signal from pulsars was modeled as second-order cyclostationary process,and corresponding simulation was done to verify its reasonableness.Based on the model,a novel method was proposed to estimate pulsars’cyclo-period by the coherent statistic of bispectrum,and then one robust strategy for periodicity searches was provided in order to eliminate its sensitivity to data amount.Using the method,the period of PSR J0437-4715 with single pulse was estimated based on original signal,and the period of PSR B1821-24 with double pulses was also estimated based on simulated signal.Results show that,compared with the classical Fourier-transform method,the algorithm is intuitive,effective,of good performance even in case of lower SNR,and also appropriate for the noncontinuous observing data.The method,though with higher computation complexity,can provide a powerful reference for period estimation of weak pulsar signal.