Relativistic VLBI Delay Model for Finite Distance Radio Source

  • Mamoru Sekido
  • Toshio Fukushima
Part of the International Association of Geodesy Symposia book series (IAG SYMPOSIA, volume 128)


When very long baseline interferometry (VLBI) is applied to observation of finite distance radio source from observer and the curvature of the the wave front cannot be approximated as plane wave. Thus current standard VLBI model (‘Consensus model’) does not have enough accuracy and an alternative precise VLBI delay model for finite distance radio source corresponding to the ‘Consensus model’ is required in observation of radio source in the solar system (e.g. planets, asteroids, and spacecraft). We derived a formular of relativistic VLBI delay model for finite distance radio source by taking into account coordinates transformation by using linearized PPN metric. This model is valid in order of several pico seconds accuracy when the radio source is at distance beyond 109 m. Our model include the ‘Consensus model’ as a special case that radio source is at infinite distance form the observer.

Key words

Very Long Baseline Interferometry Theory of Relativity Finite Distance Spacecraft Navigation 


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Copyright information

© Springer-Verlag Berlin Heidelberg 2005

Authors and Affiliations

  • Mamoru Sekido
    • 1
  • Toshio Fukushima
    • 2
  1. 1.Communications Research LaboratoryIbarakiJapan
  2. 2.National Astronomical ObservatoryTokyoJapan

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