脉冲星导航试验卫星空间计时数据的初步分析

Space observation data preliminary analysis of XPNAV-1 satellite

  • 摘要: 脉冲星导航试验卫星(X-ray pulsar-based navigation-1, XPNAV-1)是我国首颗致力于探索X射线脉冲星导航技术的空间试验平台,已在轨运行七年多,获得大批观测数据,本文收集了该卫星三年多的空间观测数据,开展了一些有益的技术探索. 首先处理分析了卫星对Crab脉冲星观测数据,得到Crab脉冲星的每轨、每天和总脉冲轮廓,结果表明,在时间维度上脉冲轮廓是稳定的,与国内外观测结果一致性较好;其次得到Crab脉冲星不同能段脉冲轮廓,分析了脉冲轮廓随能量变化特征;在能量维度上,得到了Crab脉冲星在不同脉冲相位区间的能谱,发现能谱与相位区间的脉冲强度成正比,表明我国自主研制的聚焦型X射线探测器具备良好的技术状态,也实现了卫星精确地“看得见”脉冲星的试验目标. 最后利用XPNAV-1卫星的三天观测数据,实现基于最小二乘算法的脉冲星导航试验解算,得到卫星轨道确定精度约为56.93 km,分析发现XPNAV-1星对Crab脉冲星观测误差和初始轨道误差对当前导航解算精度影响较大.

     

    Abstract: The X-ray pulsar-based navigation-1 (XPNAV-1) is China’s first space experimental platform dedicated to exploring X-ray pulsar navigation technology. It has been in orbit for over seven years, accumulating a large amount of observational data. This work collects nearly four years of space observation data from the satellite and conducts valuable technical research explorations. Firstly, the satellite’s observation data on the Crab pulsar is processed and analyzed. The pulse profiles of the Crab pulsar per orbit, per day, and the total pulse profile are obtained. The results indicate that the pulse profile is stable in the temporal dimension, showing good consistency with domestic and international observational results. Different energy range pulse profiles of the Crab pulsar are obtained, and the characteristics of pulse profile variation with energy are analyzed. In the energy dimension, the energy spectra of the Crab pulsar in different pulse phase intervals are obtained. It is found that the energy spectrum is proportional to the pulse intensity in the phase interval, indicating that the domestically developed focusing X-ray detector is in good technical condition and has achieved the experimental goal of accurately “seeing” the pulsar from the satellite. Finally, using three days of observation data from the XPNAV-1 satellite, pulsar navigation test solutions based on the least squares algorithm are achieved. The satellite’s orbit determination accuracy is approximately 56.93 km. Analysis reveals that the current navigation solution accuracy is severely affected by observation errors of XPNAV-1 towards the Crab pulsar and initial orbit errors.

     

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