基于X射线脉冲星导航试验卫星观测数据的到达时间估计

TOA estimation methods for the observation data based on the X-ray Pulsar-based Navigation-1(XPNAV-1)satellite

中国首颗X射线脉冲星导航试验卫星(X-ray Pulsar Navigation-1,XPNAV-1)搭载了两种体制的X射线探测器,其主要任务是在轨开展X射线脉冲星的探测以及进行脉冲星导航体制的验证。为了实现到达时间(Time of Arrival,TOA)的高精度估计,提出了利用阵列信号处理领域的多重信号子空间分类(Multiple Signal Classification,MUSIC)方法进行脉冲星导航的TOA估计,进行了试验仿真验证,并且对XPNAV-1观测到的蟹状星云(Crab)脉冲星的光子数据进行处理。在观测时间为协调世界时(Coordinate Universal Time,UTC)57 727.0约简儒略日(Modified Julian Day,MJD)到UTC 57 812.0 MJD内,选取了0.5~10keV频段内的121段光子观测数据,对这些数据进行了脉冲轮廓折叠,得到了Crab脉冲星的折叠轮廓,然后分别利用互相关法和MUSIC方法进行折叠轮廓的TOA估计,最后对比了两种方法的估计结果。

The first X-ray Pulsar-based Navigation-1（XPNAV-1）satellite of China operates two X-ray instruments.The purpose of the XPNAV-1 mission is to detect the X-ray pulsars′radiation photons and validate the pulsar navigation method.To acquire high-precision pulse time-of-arrival（TOA）estimation,a novel method based on the multiple signal classification（MUSIC）algorithm was proposed,then numerical simulation was done for the novel method.The data from coordinate universal time（UTC）57 727.0 MJD（modified Julian day）to UTC 57812.0 MJD of Crab pulsar observed by XPNAV-1 satellite was analyzed.Firstly,121 pieces of the observations in the 0.5~10 keV energy band were refined using epoch folding method.Secondly,the TOA of the epoch folding profiles was estimated by cross correlation method and MUSIC method.Finally,the estimations of the two methods were analyzed.