脉冲星时间标准应用研究

A preliminary pulsar timescale was obtained based on Parkes Pulsar Tinming Array long term observations for 19 millisecond pulsars with 64m radio telescope. The results shown that pulsar timing array can measure errors of atomic time TAI. Pulsar timescale obtaind indicated very good accuracy and precision which is comparable to the terrestrial timescale TT. The International Astronomical Union (IAU) time commission has set up a working group on pulsar timescale. Purpose of the working group for pulsar timescale is to carry on investication on pulsar timescale and to coordinate international cooperation in this area. Physical mechanism between pulsar and atomic timesales is quite different. This project mainly aims at algorithm for producing and keeping pulsar-based timescale with pulsar timing array abservations. Suitable algorithm for pulsar timescale should be designed specially because pular timing observation is usualy irregular and sample rate is much lower than that atomic clock comparison. In addition the model and timing noise for pulsar clock are different from atomic clock. The main research objects include precision pulsar timing model, ensemble pulsar timescale algorithm and error analysis, method of producing and keeping a new timescale based on combined pulsar-actomic clocks in order to make timely time service application. Considering time service application with chinese pulsar timing observation in the near future an investigatin and design on chinese pulsar timing array project is also important.

脉冲星时是与原子时物理机制不同的时间尺度。国际上，利用毫秒脉冲星计时观测的多年资料，初步分析研究得到脉冲星时间标准，其精度能够与地球时TT（BIPM）相比，能够检测国际原子时TAI的系统误差。国际天文学会（IAU）时间专业委员会已经成立脉冲星时间标准工作组，旨在研究和推动脉冲星时间标准应用于时间服务工作。本项目在原子时算法基础上，根据脉冲星计时观测非等间隔采样、采样率偏低特点以及脉冲星钟模型和噪声特征，重点研究和试验合适的脉冲星时产生和保持方法。其中包括：脉冲星计时模型研究；综合脉冲星时算法与误差分析；能够用于实时性时间服务的脉冲星时与原子时结合时间尺度的产生和保持方法。在脉冲星时算法研究基础上，提出支持脉冲星时间服务的脉冲星计时阵观测方案。

脉冲星时是与原子时物理机制不同的时间尺度。国际上，利用毫秒脉冲星计时观测的多年资料，初步分析研究得到脉冲星时间标准，其精度能够与地球时TT（BIPM）相比，能够检测国际原子时TAI 的系统误差。本项目主要开展了脉冲星计时模型研究；综合脉冲星时算法与误差分析；基于洛南40米脉冲星观测系统的建立及观测研究。本项目利用国际上观测精度最高的Parkes脉冲星计时阵PPTA观测数据建立了综合脉冲星时，并评估了其稳定度，2.6年后的稳定度优于中科院国家授时中心保持的地方原子时；另外，利用PPTA精度最高的两颗脉冲星开展了脉冲星钟模型精度分析，定量给出了目前脉冲星钟模型约每4-5年精度提高一个量级。通过利用建立的钟模型开展预报精度分析，基于J0437-4715的数据建立钟模型其脉冲星时自主保持精度为5年内相对于TT偏差小于1微秒；利用中科院国家授时中心洛南40米射电望远镜平台，建立了脉冲星计时观测系统，为后续脉冲星时的建立及应用试验提供了良好的平台。