Crab脉冲星标准脉冲轮廓更新对计时精度的改进

Improvement of timing precision by updating standard pulse profile of Crab pulsar

对于脉冲星试验01星的两年实测数据,针对蟹状星云脉冲星星历经历了多次更新的特点,提出了更新标准脉冲轮廓进行X射线计时的改进方法。以一系列观测时长为实测数据分组,再采用改进后的方法进行计时分析并与改进前的结果进行对比。通过对比改进前后的计时结果,发现改进方法得到的计时残差的均方根(root mean square, RMS)平均降低了14.2%,定位精度平均提高了14.4%,估计原子钟相对频率偏差的精度平均提高了26.2%,体现了改进方法处理经历多次星历更新的Crab脉冲星观测数据的合理性和优越性。此外,改进方法对脉冲星试验01星两年观测数据的稳定度σ_(z)没有量级上的改进,说明改进方法对Crab脉冲星时间稳定度的影响不大。

For two-year measured data of X-ray Pulsar Navigation-1(XPNAV-1),according to the characteristic of Crab pulsar ephemeris that has undergone multiple updates,an improved method of updating the standard pulse profile for X-ray timing is proposed.The measured data are grouped by a series of observation time,and then the improved method is used to conduct timing analysis and the timing results are compared with the results before improvement.By comparing the timing results before and after improvement,it shows that the root mean square(RMS)of timing residuals obtained by the improved method has decreased by 14.2%on average,the positioning precision has improved by 14.4%on average,and the precision of estimating the relative frequency deviation of atomic clocks has improved by 26.2%on average,which illustrate the rationality and superiority of the improved method in processing the observation data of Crab pulsar updating ephemeris many times.In addition,the improved method has no improvement on the stability σ_(z) of XPNAV-1's two-year observation data,which shows that the improved method has little influence on the time stability of Crab pulsar.