Register now After registration you will be able to apply for this opportunity online.
Impact of satellite mega-constellations on VLBI observations
Very Long Baseline Interferometry (VLBI) is versatile space geodetic technique, measuring radiation from extragalactic radio sources. VLBI supports a wide range of applications, including the determination of the terrestrial and celestial reference frames, measurements of the full set of Earth orientation parameters, and the determination of geophysical models. Due to its observation principle, VLBI observations have to be actively planned and organized between the radio telescopes.
In recent years, a dramatic growth in the number of satellites emitting radio frequencies can be seen. Most notably is the Starlink system, with more than five thousand satellites being in orbit already. These satellite mega-constellations threaten VLBI observations since their emitted artificial radio signals interferes with the natural radio signal emitted from the extragalactic radio sources, especially if the satellite is aligned with the observed radio source. So far, no active measures are in place to avoid VLBI observations in such cases.
Within this work, it will be investigated if and how many VLBI observations may be affected by interferences from Starlink satellites in the near future. Therefore, the current and potential future Starlink constellations will be analyzed and satellites passing over stations, expressed via their azimuth and elevation angles, will be cross-checked with the azimuth and elevation angles of the observed extragalactic radio sources. Satellite TLE files will be utilized to calculate the satellite orbit for this purpose.
Within this work, an optimal strategy for the determination of the satellite position w.r.t. interpolating positions will be determined. Empirical models will be derived to determine the estimation frequency as a function of the orbital parameters. Based on these investigations, the potential of 3-dimensional masks (azimuth, elevation, time) in VLBI scheduling will be evaluated. Finally, by using algorithms to actively avoid satellite passes in VLBI observations, the impact of Starlink on geodetic VLBI will be investigated. Therefore, successive satellite orbit solutions will be compared to investigate the provided orbit solution accuracy based on TLE files to properly assess the required safety margin for the active avoidance algorithm.
Within this work, it will be investigated if and how many VLBI observations may be affected by interferences from Starlink satellites in the near future. Therefore, the current and potential future Starlink constellations will be analyzed and satellites passing over stations, expressed via their azimuth and elevation angles, will be cross-checked with the azimuth and elevation angles of the observed extragalactic radio sources. Satellite TLE files will be utilized to calculate the satellite orbit for this purpose. Within this work, an optimal strategy for the determination of the satellite position w.r.t. interpolating positions will be determined. Empirical models will be derived to determine the estimation frequency as a function of the orbital parameters. Based on these investigations, the potential of 3-dimensional masks (azimuth, elevation, time) in VLBI scheduling will be evaluated. Finally, by using algorithms to actively avoid satellite passes in VLBI observations, the impact of Starlink on geodetic VLBI will be investigated. Therefore, successive satellite orbit solutions will be compared to investigate the provided orbit solution accuracy based on TLE files to properly assess the required safety margin for the active avoidance algorithm.
Matthias Schartner (mschartner@ethz.ch), Prof. Benedikt Soja (soja@ethz.ch)
Matthias Schartner (mschartner@ethz.ch), Prof. Benedikt Soja (soja@ethz.ch)
Impact of satellite mega-constellations on VLBI observations.pdf
