2-6 September 2024
CJD Bonn Castell
Europe/Berlin timezone
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Contribution

Benefits of VLBI observations to Next-Generation GNSS satellites

Speakers

  • Prof. Susanne GLASER

Primary authors

Co-authors

Content

This study explores the benefits of placing a Very Long Baseline Interferometry (VLBI) transmitter onboard a next-generation Global Navigation Satellite Systems (GNSS) satellite. Classical VLBI to extra-galactic radio sources is the only space geodetic technique that can determine all five Earth Orientation parameters (EOPs) in an absolute sense, including UT1-UTC and Celestial Intermediate Poles (CIPs), which are needed by other satellite techniques and interplanetary spacecraft as a priori information. However, classical VLBI is not sensitive to the Earth’s origin, namely the geocenter; therefore, No Net Translation (NNT) conditions must be imposed in addition to No Net Rotation (NNR) conditions. Adding satellite observations could help resolve this issue by providing access to the geocenter. In the current study, we simulate a VLBI network with 20 legacy and future stations to observe a VLBI transmitter on a single Galileo-like satellite along with extra-galactic radio sources simultaneously, spanning a time period of one year. Dynamic Precise Orbit Determination (POD) to the satellite is performed, and orbital parameters are estimated along with geodetic parameters such as station positions, the complete set of EOPs, and geocenter coordinates, and we discuss the performance of all estimated parameters. Furthermore, an optimal ratio of satellite and source observations should provide adequate geocenter information without exacerbating the geodetic parameters primarily estimated by classical VLBI. We found an optimal ratio of satellite observations of approximately 30% of the total observations.