非等间隔计时数据的X射线脉冲星周期快速搜索算法

利用X射线脉冲星信号的计时信息实现航天器深空导航具有重要意义,精确的时间模型(周期及周期导数)是获得高精度自主导航的基础.针对X射线光子并非等间隔地到达探测器的特点,在对比分析两种非等间隔数据处理方法(x2量评估方法和Lomb算法)的基础上,提出了用Lomb算法估计脉冲星周期初值,进一步使用x2量评估方法精化周期值的方法.同时运用快速傅里叶变换算法的思想对Lomb算法进行改进,较大地提高了程序的运算效率.最后利用X射线源仿真系统的计时数据对算法进行试验分析,搜索出准确的脉冲星周期和折叠出正确的脉冲轮廓.

Quick search algorithm of X-ray pulsar period based on unevenly spaced timing data

Timing information of X-ray pulsar signal is of the vital significance for realizing the autonomous navigation of spacecraft in deep space. The accurate timing model (period and period derivation) is the foundation of achieving high-precision auto-navigation solutions. Because the data that the X-ray photons arrive at the detector are unevenly spaced, both χ² evaluation method and Lomb algorithm are analyzed. The idea is brought forward that the initial value of pulsar period is gained using the χ² evaluation method, then the result of period is refined by Lomb algorithm. Meanwhile, the Lomb algorithm is ameliorated by the idea of fast Fourier transform algorithm, the efficiency of operation is enhanced highly. Finally the exact pulsar period is estimated, and correct pulse profile is replicated using the measured timing data from the X-ray source simulation system which used to validate the algorithm.