基于实测数据的脉冲星时自主保持精度分析

Analysis of pulsar time keeping accuracy using observation data

脉冲星钟模型保持方法和脉冲星时自主保持精度是决定脉冲星时应用精度的关键。根据地球时TT发布的特点以及脉冲星自转稳定特点,提出基于滑动累积窗口的脉冲星钟模型保持方法。首先利用IPTA第2批发布的2颗脉冲星观测数据开展钟模型保持精度分析,在13年以上的时间窗口内2颗源的自转频率测量值相对于平均值波动幅度在10^(-13)Hz之内,且随着时间窗口累积增加钟参数测量精度单调提高;其次,利用观测数据分析钟模型在滑动预报下的脉冲星时自主保持精度和稳定度,J0437-4715在13.58年内自主保持的脉冲星时与TT(BIPM15)偏差的RMS(root mean square)为0.454μs,长期(13.58年)稳定度为1.77×10^(-15),J1713+0747在17.46年内保持的脉冲星时与TT(BIPM15)偏差为2.471μs,长期(17.46年)稳定度为6.62×10^(-17),相对于最佳保持脉冲星时的精度分别降低24%和0.16%,但提升了短期(<1年)稳定度,长期稳定度略有恶化。

The maintenance method of pulsar clock model and the precision of pulsar time keeping are the key to the precision of pulsar timing application.According to the characteristics of the release of time reference TT and the characteristics of pulsar rotation stability,a pulsar clock model measurement based on sliding cumulative observation data span window is proposed.Firstly,the pulsar clock model maintenance accuracy analysis is carried out using the observation data of two pulsars from the 2nd data release of IPTA.The measured values of the rotation frequency of two pulsars fluctuate less than 10^(-13) Hz relative to the average value within the data span window more than 13 years,and the clock parameter measurement accuracy increases monotonously with the increase of the data span window;Secondly,the observation data are used to analyze the accuracy of pulsar time keeping under the sliding window prediction of the clock model,the deviation(RMS)of time keeping of pulsar J0437-4715 relative to TT(BIPM15)is 0.454μs in 13.58 year,long-term(13.58 year)stability is 1.77×10^(-15),and the deviation of time keeping of pulsar J1713+0747 relative to TT(BIPM15)is 2.471μs in 17.46 year,long-term(17.46 year)stability is 6.62×10^(-17),accuracy decreases by 24%and 0.16%respectively when compared with the best maintained pulsar time,but the short-term(<1 year)stability was improved,and the long-term stability was slightly deteriorated.