Considerations of VLBI transmitters on Galileo satellites

For directly linking the dynamical reference frame of satellite orbits to quasi-inertial extra-galactic radio sources, observations satellites with Very Long Baseline Interferometry (VLBI) technique are only conceivable method. Hence, should be embedded in VLBI network sessions during which also natural sources observed. this reason, it would most practical if artificial signal generated at for covers same frequency bands as regularly observed by telescopes and have a similar flux density across bandwidth these sources. The use Global Navigation Satellite Systems (GNSS) such Galileo system is advisable because they well monitored terms precise orbit determination altitude allows common visibilities many telescopes. So far, generation on GNSS dedicated has not been realized yet, partly suitable equipment considered depth. In addition, aspects, legal implications technical complications, yet addressed. publication, we compiled various aspects generating an satellite. We describe emitting including design study necessary Since geodetic currently transition period from traditional S X band broadband Observing System (VGOS), proposed generates both setups. restrictions installation satellite, power consumption, weight, size. mainly consists three devices: noise source, amplifier, antenna. A diode used source. This amplified set low amplifiers then radiated spiral were chosen market, but antenna was newly designed simulated. output chain tested using baseband data simulator, correlated fringe-fitted validation. instrumentation here easy constructed, will still laboratory together instruments actual