Advertisement

Simulating GPS Radio Occultation Using 3-D Ray Tracing

  • R. Norman
  • J. Le Marshall
  • K. Zhang
  • C. S. Wang
  • B. A. Carter
  • Y. Li
  • S. Gordon
Conference paper
Part of the International Association of Geodesy Symposia book series (IAG SYMPOSIA, volume 139)

Abstract

Numerical 3-D ray tracing techniques are commonly used for calculating the path of an electromagnetic signal in a medium specified by a refractive index that depends upon position. Numerical ray tracing is an important tool for applications of L-band frequency propagation such as GPS Radio Occultation (RO), where accurate and near real-time results are required. In this study, 3-D numerical ray tracing techniques are used to simulate GPS signals received by the Low Earth Orbit (LEO) satellites and to investigate their variability as a function of time and position due to the refractivity gradients in the ionosphere and the lower atmosphere. The GPS signal paths from the GPS to LEO satellites are simulated with an emphasis on the signal paths propagating through regions of the ionosphere where the refractive gradients are greatest. The effects of the Earth’s magnetic field on the L-band RO propagation paths are also investigated.

Keywords

Ionosphere Refractivity Ray tracing Radio occultation 

Notes

Acknowledgements

This work is supported in part by the Australian Space Research Program project of “Platform Technologies for Space, Atmosphere and Climate” endorsed to a research consortium led by RMIT University.

References

  1. Bird MK, Asmar SW, Brenle JP, Edenhofer P, Funke O, Patzoid M, Volland H (1992) Ulysses radio occultation observations of the Io plasma torus during the Jupiter encounter. Science 257:1531–1535CrossRefGoogle Scholar
  2. Bilitza D, Reinisch B (2008) International reference ionosphere 2007: improvements and new parameters. Adv Space Res 42(4):599–609CrossRefGoogle Scholar
  3. Cucurull L, Derber JC, Treadon R, Purser RJ (2007) Assimilation of global positioning system radio occultation observations into NCEP’s global data assimilation system. Mon Weather Rev 135:3174–93CrossRefGoogle Scholar
  4. Fjeldbo G, Kliore AJ, Eshleman VR (1971) The neutral atmosphere of Venus as studied with Mariner V radio occultation experiments. Astron J 76:123–140CrossRefGoogle Scholar
  5. Hajj GA, Ibanez-Meier R, Kursinski ER, Romans LJ (1994) Imaging the ionosphere with global positioning system. Int J Imaging Syst Technol 5:174–184CrossRefGoogle Scholar
  6. Hardy KR, Hajj GA, Kurinski ER (1993) Accuracies of atmospheric profiles obtained from GPS occultations. In: Proceedings of the ION-GPS 93 conference, Institute of Navigation, Salt Lake City, pp 1545–1557Google Scholar
  7. Healy SB, Eyre JR (2000) Retrieving temperature, water vapor and surface pressure information from refractive index profiles derived by radio occultation: a simulation study. Q J R Meteorol Soc 126:1661–83CrossRefGoogle Scholar
  8. Hernandez-Pajares M, Juan JM, Sanz J (2000) Improving the Abel inversion by adding ground GPS data to LEO radio occultations in ionospheric sounding. Geophys Res Lett 27:2473–2476CrossRefGoogle Scholar
  9. Le Marshall J, Xiao Y, Norman R, Zhang K, Rea A, Cucurull L, Seecamp R, Steinle P, Puri K, Le T (2010) The beneficial impact of radio occultation observations on Australian region forecasts. Aust Meteorol Oceanogr J 60:121–125Google Scholar
  10. Le Marshall J, Xiao Y, Norman R, Zhang K, Rea A, Cucurull L, Seecamp R, Steinle P, Puri K, Le T (2012) The application of radio occultation for climate monitoring and numerical weather prediction in Australian region. Aust Meteorol Oceanogr J 62:323–334Google Scholar
  11. Norman RJ, Bennett JA, Dyson PL, Le Marshall J, Zhang K (2013) A ray-tracing technique for determining ray tubes in anisotropic media. IEEE Trans Antennas Propag 61(5):2664–2675CrossRefGoogle Scholar
  12. Norman RJ, Dyson PL, Yizengaw E, Le Marshall J, Wang C-S, Carter B, Wen D, Zhang K (2012) Radio occultation measurements from the Australian micro satellite FedSat. IEEE Trans Geosci Remote Sensing 50(11):4832–4839. doi: 10.1109/TGRS.2012.2194295 CrossRefGoogle Scholar
  13. Phinney RA, Anderson DL (1968) On the radio occultation method for studying planetary atmospheres. J Geophys Res 73:1819–1827CrossRefGoogle Scholar
  14. Rocken C, Anthes R, Exner M, Hunt D, Sokolovskiy S, Ware R, Gorbunov M, Schreiner W, Feng D, Herman B, Kuo Y, Zou X (1997) Analysis and validation of GPS/MET data in the neutral atmosphere. J Geophys Res 102:29849–29866CrossRefGoogle Scholar
  15. Zhang K, Fu E, Silcock D, Wang Y, Kuleshov Y (2011) An investigation of atmospheric temperature profiles in the Australian region using collocated GPS radio occultation and radiosonde data. Atmos Meas Tech 4:2087–2092CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • R. Norman
    • 1
  • J. Le Marshall
    • 1
    • 2
  • K. Zhang
    • 1
  • C. S. Wang
    • 1
  • B. A. Carter
    • 1
  • Y. Li
    • 1
  • S. Gordon
    • 1
  1. 1.Satellite Positioning for Atmosphere, Climate and Environment (SPACE) Research CentreRMIT UniversityMelbourneAustralia
  2. 2.Bureau of MeteorologyMelbourneAustralia

Personalised recommendations