Research On Frequency Search And Timing Model Of X-ray Pulsars

Pulsar is a neutron star rotating at a high speed.It radiates pulse signals to the solar system with a stable period.It is known as the most stable clock in nature.The extremely high rotational stability of pulsars creates conditions for the study of pulsar timing.according to the rotational energy loss mechanism of pulsars,a pulsar timing model can be established.The ideal pulsar timing model can accurately predict the pulsar rotation frequency and phase information at a certain time,and provide accurate phase prediction for x-ray pulsar navigation.In order to meet the needs of X-ray pulsar deep space navigation,this paper studies the method of establishing X-ray pulsar timing model.In the process of establishing the X-ray pulsar timing model,the rotation frequency search for single observation data is very important.In this paper,the following studies have been carried out on the rotation frequency search:(1)based on RXTE,the phenomenon of"Maoci"in the?~2-test cost function of crab pulsar measured data has been deeply studied.The cause of glitch phenomenon is explained,and the simulation scheme of photon toa sequence with"non-pulsar photon toa characteristic"is designed.the simulation results show that the recurrence rate of?Maoci?is as high as 77.5%.(2)the frequency domain truncation point of pulsar photon toa sequence is estimated by K-T method,and the simulation results show that the estimated value of K-T method is consistent with the predicted value,which provides a reliable reference for the selection of smooth parameter m;(3)in this paper,an FFT-based power spectral integration frequency domain search algorithm is proposed.The estimation performance of the algorithm is comparable to that of theZ_m~2-test for large flow observation data,and the algorithm has high efficiency.In this paper,the modeling framework of X-ray pulsar timing model is discussed,and two kinds of phase-wrap phenomena in timing residuals are summarized and analyzed.Then,the timing model based on the measured data of X-ray pulsar is studied in this paper.Using XPNAV-1 to study the short-term timing model of crab pulsar about one month's timing observation data,and put forward a scheme that does not need the initial radio parameters.The experimental results show that compared with other existing models,the model established in this paper is the most suitable.The modeling of long-term timing model was studied using RXTE's observation data of PSR B1509-58 for 15 years.In this paper,the low-frequency red noise in pulsar long-term timing model is analyzed,the method of removing"whitening"of timing noise is studied,and a method of searching pulsar position by using root-mean-square error of residual after pre-whitening fitting is proposed.