Experimental Astronomy

, Volume 48, Issue 1, pp 49–64 | Cite as

Improvement of the pointing precision of the Tianma radio telescope with an inclinometer measurement system

  • Li FuEmail author
  • Jinqing Wang
  • Yongbin Jiang
  • Linfeng Yu
  • Rongbing Zhao
  • Quanbao Ling
  • Bingen Yang
  • Qinghui Liu
  • Zhiqiang Shen
Original Article


To assure high pointing precision of the Tianma radio telescope (TMRT), new models based on a inclinometer measurement system are added to the classical pointing model. This involves four main tasks. Firstly, the inclinometer measurement system is set up and its precision is evaluated. Secondly, a feedback control strategy for pointing error for the turbulences of uneven azimuth track and thermal deformations of alidade is implemented. Thirdly, after removing the linear effect of uneven track, sine fitting inclinometer data obtains the model of nonlinear effect of azimuth-track-level unevenness. The nonlinear effect is less than ±5 arc-sec. The azimuth angles associated with large pointing error show a good agreement with those corresponding to poor track unevenness. Finally, the TMRT inclinometers monitor the effect of thermal deformations of alidade on the pointing precision of elevation from stow position, to observing almost motionless radio source, to arbitrary postures of radio telescope. The measured data after subtracting other affected factors of inclinometer including intrinsic drift, azimuth-track unevenness, variation of the center of gravity have similar tendency with the simulated results of finite element model (FEM). Applying established real-time modified model to observe the radio source 2334 + 8226, the checking results show that the pointing precision improved 65%.


Radio telescope Pointing errors Inclinometer Thermal effects Alidade Azimuth track 



We are grateful for the assistance of the TMRT operators during the observations. This work was supported by the National Key Basic Research and Development Program (Grant No. 2018YFA0404702), the National Natural Science Foundation of China (Grant No.U1631114, 11873015, 11203062), the CAS Key Technology Talent Program, the Knowledge Innovation Program of CAS (Grant No. KJCX1-YW-18), the Scientific Program of Shanghai Municipality (Grant No. 08DZ1160100), the Key Laboratory for Radio Astronomy of CAS, the Key Laboratory of Planetary Sciences of CAS, the CAS Scholarship.


  1. 1.
    Wielebinski, R., Junkes, N., Grahl, B.H.: The Effelsberg 100-m radio telescope: construction and forty years of radio astronomy. J. Astron. Hist. Herit.14(1), 3–21 (2011)ADSGoogle Scholar
  2. 2.
    Wielebinski, R.: The Effelsberg 100-m radio telescope. Naturwissenschaften. 58(3), 109–116 (1971)ADSCrossRefGoogle Scholar
  3. 3.
    Sivasankaran, S., Roger, N., Lee, K., et al.: An overview of the green Bank telescope. IEEE Antennas and Propagation Society International Symposium (APSURSI) (1999)Google Scholar
  4. 4.
    Bolli, P., Orlati, A., Stringhetti, L., et al.: Sardinia radio telescope: general description, technical commissioning and first light. J. Astron. Inst. Neth. 4(3&4), 1550008–1–20 (2016)Google Scholar
  5. 5.
    Isabella, P., Matteo, M., Andrea, T., et al.: The Sardinia radio telescope: from a technological project to a radio observatory. Astron. Astrophys. 608, A40), 1–A40),26 (2017)Google Scholar
  6. 6.
    Shen, Z.Q.: Status of Shanghai Tianma radio telescope. Proc. ATITC. (2015)Google Scholar
  7. 7.
    Dong, J., Fu, L., Liu, Q.H., et al.: Measuring and analyzing thermal deformations of the primary reflector of the Tianma radio telescope. Exp. Astron. 45, 397–410 (2018)ADSCrossRefGoogle Scholar
  8. 8.
    Yan, Z., Shen, Z.Q., Wu, X.J., et al.: Single-pulse radio observations of the galactic center magnetar PSR J1745–2900. ApJ. 814(1), 5–12 (2015)ADSCrossRefGoogle Scholar
  9. 9.
    Cheng, J.Q.: The principles of astronomical telescope design. Astrophys. Space Sci. Libr. (2009)Google Scholar
  10. 10.
    Guiar, C. N., Lansing, F. L.: Antenna pointing systematic error model derivations. TDA Progress Report 42-88. 36–46 (1986)Google Scholar
  11. 11.
    Yu, L.F., Wang, J.Q., Zhao, R.B., et al.: Pointing model establishment of TM65 m radio telescope. Acta Astronomica Sinica. 56(2), 165–177 (2015)ADSGoogle Scholar
  12. 12.
    Gawronski, W., Baher, F., Gama, E.: Track-level-compensation look-up table improves antenna pointing precision. Proc. SPIE Int. Soc. Opt. Eng. 6273, 1–17 (2006)Google Scholar
  13. 13.
    Gawronski, W., Baher, F., Quintero, O.: Azimuth track level compensation to reduce blind pointing errors of the deep space network antennas. IEEE Antennas Propag. Mag.42(2), 17–27 (2000)CrossRefGoogle Scholar
  14. 14.
    Ambrosini, R., Grueff, G., Morsiani, M., et al.: Analysis of the alidade temperature behavior of the Medicina VLBI radio telescope. Astrophys. Space Sci.239, 247–258 (1996)ADSCrossRefGoogle Scholar
  15. 15.
    Pisanu, T., Buffa, F., Poppi, S., et al.: The SRT inclinometer for monitoring the track and the thermal gradient effects on the alidade structure. In: Proc. SPIE. Astronomical Telescopes + Instrumentation Symposium, vol. 9145, id. 91454R, pp. 10 (2014)Google Scholar
  16. 16.
    Fu, L., Ling, Q.B., Geng, X.G., et al.: The alidade temperature behaviour of TM65m antenna and its effects on pointing precision. In: Proc. SPIE. Astronomical Telescopes + Instrumentation Symposium, vol. 9912, id. 99124J, pp. 7 (2016)Google Scholar
  17. 17.
    Constantikes, K.: Estimating the GBT pointing model. PTCS Project Note 63.0. (2008)Google Scholar
  18. 18.
    Fu, L., Ling, Q.B., Zhao, R.B., et al.: Measurements of foundation and track of TM65m and analysis of its effect on pointing. Infrared and Laser Engineering. 45(11), 183–189 (2016)Google Scholar
  19. 19.
    Penalver, J., Lisenfeld, U., Mauersberger, R.: Pointing with the IRAM 30m telescope. Proc. SPIE. Astronomical telescopes & instrumentation. 4015, 632–640 (2000)ADSGoogle Scholar
  20. 20.
    Qian, H.L., Liu, Y., Fan, F., et al.: Surface precision analysis on main reflector of 65 m antenna structure. International Journal of Space Structures. 41(11), 3027–3033 (2012)Google Scholar
  21. 21.
    Qian, H.L., Liu, Y., Fan, F., et al.: Analysis of the precision of the structural performance of the 65 m – antenna reflector. International Journal of Space Structures. 28(1), 15–26 (2013)CrossRefGoogle Scholar
  22. 22.
    Greve, A., Bremer, M.: Thermal Design and Thermal Behavior of Radio Telescopes and their Enclosures, vol. 9. Springer-Verlag, Berlin Heidelberg (2010)CrossRefGoogle Scholar
  23. 23.
    Wang, J.Q., Yu, L.F., Zhao, R.B., et al.: High precision pointing error detection method for large radio telescope. Scientia Sinica Physica, Mechanica & Astronomica. 47(12), 129504–102017 (2017)ADSCrossRefGoogle Scholar

Copyright information

© Springer Nature B.V. 2019

Authors and Affiliations

  1. 1.Division of Radio Astronomy Science and Technology, Shanghai Astronomical ObservatoryShanghaiChina
  2. 2.Department of Aerospace and Mechanical EngineeringUniversity of Southern CaliforniaLos AngelesUSA

Personalised recommendations