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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2023, Vol. 44 ›› Issue (3): 526610-526610.doi: 10.7527/S1000-6893.2021.26610

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On⁃orbit stability analysis of FXPT on XPNAV⁃1

Qingyong ZHOU1,2(), Linli YAN3, Liansheng LI4, Laiping FENG1,2, Yongqiang SHI4, Pengfei SUN5, Liu FANG1,2, Long WANG1,2   

  1. 1.Xi’an Institute of Surveying and Mapping,Xi’an  710054,China
    2.State Key Laboratory of Geographic Information Engineering,Xi’an  710054,China
    3.School of Mathematics and Physics,Anhui Jianzhu University,Hefei  230601,China
    4.Beijing Institute of control engineering,Beijing  100090,China
    5.39th Research Institute of China Electronics Technology Corporation,Xi’an  710076,China
  • Received:2021-11-02 Revised:2021-11-30 Accepted:2022-01-07 Online:2023-02-15 Published:2022-01-11
  • Contact: Qingyong ZHOU E-mail:zjlzqy1986@163.com
  • Supported by:
    National Natural Science Foundation of China(42004004);National Key Basic Research Development Plan(2020YFB0505800);Natural Science Research Project of Colleges and Universities in Anhui Province(KJ2019A0787);Doctor Startup Fund of Anhui University of Architecture(2019QDZ14)

Abstract:

The Focusing X-ray Pulsar Telescope (FXPT) is the core payload of the first X-ray Pulsar-Based Navigation (XPNAV-1) Satellite. The FXPT is the first focused X-ray telescope in China, and its on-orbit stability has always been concerned. Firstly, the feasibility of using XPNAV-1 observations of supernova remnants with characteristic spectrum radiation to evaluate the on-orbit stability of the FXPT is analyzed. It is found that the fitted FXPT energy response parameters have large errors, and the lack of long-term supernova remnants observations makes it difficult to support the long-term stability analysis of the telescope’s on-orbit performance. Secondly, the 1 455 times observations with an exposure time of 4.1×106 s of the Crab Pulsar from the XPNAV-1 from November 2016 to November 2019 are processed and analyzed. It is found that there are a large number of X-ray photons near 9.5 keV in the FXPT for a long time, and their energy distribution curve approximates a Gaussian distribution. After excluding the possibility of radiation from the pulsar, it is inferred that it comes from the signal beyond the upper threshold of FXPT. It is also found that there exists characteristic spectral line radiation at the energy of 7.5 keV, which may come from the stimulated radiation of Ni, the telescope lens material. Then, a method is proposed to monitor the on-orbit stability of telescope by jointly using the its intrinsic characteristic spectrum and the signal beyond the upper threshold. An analysis of the spectrum of the Crab observed by XPNAV-1 Satellite in the past four years shows that the performance of FXPT tends to be stable after October 2017. This method effectively overcomes the shortcoming that XPNAV-1 is not equipped with a radiation calibration device. The integrated pulse profile of the Crab is also recovered and the similarity of this pulse profile with that from RXTE is 98.6%, demonstrating that the FXPT can accurately obtain the pulse profile of the Crab.

Key words: Focusing X-ray Pulsar Telescope (FXPT), the first X-ray Pulsar Navigation (XPNAV-1) satellite, Crab pulsar, pulse profile, photon energy distribution

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