脉冲星计时残差的影响因素研究

发布时间：2018-09-14 06:54

【摘要】：脉冲星时频标准有成为天文时间标准的潜力，对脉冲星计时和导航的研究也越来越深入、广泛，而脉冲星计时残差的研究对脉冲星应用的研究至关重要。通过对脉冲星计时残差进行时域和频域的分析，可以得到脉冲星计时残差的影响因素，进而避免或者消除这些误差影响，得到白化的更小的计时残差，拟合得到精确的计时模型，精化脉冲星计时参数，更好的服务于脉冲星应用研究。本论文介绍了脉冲星计时数据处理与计时模型的拟合，通过实例分别分析了脉冲星计时参数误差和非白化噪声对计时残差的影响，进而通过理论和数据分析进行阐述和验证。对于脉冲星计时处理，通过合并观测数据，折叠、消色散得到高信噪比脉冲轮廓，进而得到脉冲星脉冲到达时间，然后经过延迟项改正和坐标时的转化，与计时模型相位进行比较，得到计时残差，对计时残差进行线性奇异值分解和最小二乘拟合，寻找更优的计时模型。由于脉冲星的计时参数的误差，会影响计时模型的准确性，这又会反映在计时残差中，文章通过不同的参数误差对计时残差的影响趋势分析，，分别研究脉冲星的自转参数、天体测量参数、双星参数等参数的参数误差对计时残差的影响，得出自转频率、赤经、赤纬、双星轨道周期等一些参数对计时残差的影响明显，需要对这些参数进行精确测量。同时我们可以根据得到的残差的趋势推测影响计时残差的因素，进而消除误差影响。最后讨论对一些存在计时噪声的残差进行白化。运用差分预处理对红噪声进行频谱分析，通过傅里叶转换得到联合协方差矩阵，进而得到楚列斯基转换矩阵，对计时残差进行重复的白化；然后给出了对红噪声和白噪声相当的计时残差进行白化的方法，直接求其协方差矩阵，进而通过楚列斯基方法进行白化。通过研究可以得出，楚列斯基方法对含红噪声的计时残差的白化效果明显；相对于白化前残差，对白化后的计时残差进行拟合，得到的计时模型更加精确。
[Abstract]:Pulsar time-frequency standard has the potential to become the astronomical time standard, and the research on pulsar timing and navigation is more and more in-depth, and the study of pulsar timing residuals is very important to the application of pulsars. By analyzing the pulsar timing residuals in time domain and frequency domain, the influencing factors of pulsar timing residuals can be obtained, and then these errors can be avoided or eliminated, and less whitening time residuals can be obtained. The precise timing model is obtained to refine the timing parameters of pulsars and to better serve the application research of pulsars. This paper introduces the processing of pulsar timing data and the fitting of timing model, analyzes the influence of pulsar timing parameter error and non-whitening noise on the timing residuals by examples, and then explains and verifies by theory and data analysis. For pulsar timing processing, the pulse profile of high SNR is obtained by combining observed data, folding and eliminating dispersion, and then the pulse arrival time is obtained, then the delay term is corrected and the coordinate is transformed. Compared with the timing model phase, the timing residuals are obtained, and the timing residuals are analyzed by linear singular value decomposition and least square fitting to find a better timing model. As the error of timing parameters of pulsar will affect the accuracy of timing model, which will be reflected in the timing residuals, the paper studies the rotation parameters of pulsars through the trend analysis of the influence of different parameter errors on timing residuals. The influence of parameter errors of parameters such as astrometric parameters and binary satellite parameters on the timing residuals is obtained. Some parameters, such as rotation frequency, longitude, latitude and binary orbit period, have obvious effects on the timing residuals, and these parameters need to be accurately measured. At the same time, we can infer the factors that affect the timing residuals according to the trend of the residual errors, and then eliminate the influence of errors. Finally, the whitening of some residuals with timing noise is discussed. The frequency spectrum of red noise is analyzed by differential preprocessing, and the joint covariance matrix is obtained by Fourier transform, and then the Trilesky transformation matrix is obtained, and the timing residuals are repeatedly whitened. Then, the method of whitening the time residuals of red noise and white noise is given, and the covariance matrix is obtained directly, and then whitened by Chulesky method. It can be concluded that the Chulesky method has obvious whitening effect on the timing residuals with red noise, and compared with the pre-whitening residuals, the timing residuals after whitening are fitted and the timing models obtained are more accurate.
【学位授予单位】：中国科学院研究生院（国家授时中心）
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：P145.6;P127.1

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