Séminaires

TBD
Quihan He (Durham University or Heidelberg)

Salle de réunion AGO (local -1/14), Institut d'Astrophysique et de Géophysique
Bâtiment B5c, Quartier Agora, Allée du 6 Août, 19C, B-4000 Liège 1 (Sart-Tilman)

Genesis: the ESA mission to measure Earth down to the millimeter
Gilles Wautelet (LPAP, STAR Institute, ULiège)

Salle de réunion AGO (local -1/14), Institut d'Astrophysique et de Géophysique
Bâtiment B5c, Quartier Agora, Allée du 6 Août, 19C, B-4000 Liège 1 (Sart-Tilman)

Genesis is an ESA space geodetic mission that will be launched in early 2029. It aims at improving and homogenizing the International Terrestrial Reference Frame (ITRF), with a target accuracy for station position and velocity of 1mm and 0.1mm/year, respectively. In order to achieve this high-accuracy level, Genesis will collocate, for the first time ever, the four space geodetic techniques on a single platform: the spacecraft will host a Global Navigation Satellite Systems (GNSS) receiver, a Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) receiver, a Satellite Laser Ranging (SLR) retroreflector and a Very Long Baseline Interferometry (VLBI) transmitter. Because these instruments use radio signals (except SLR) that travel into the Earth’s ionosphere and plasmasphere, the contribution of these ionized layers of the atmosphere must be accurately modeled and mitigated to ensure precise and reliable measurements that will be used to compute the ITRF. After the presentation of the Genesis mission and the related geodetic framework, we investigate the magnitude and the variability of the ionospheric contribution on the future Genesis observables. Then, based on simulations of GNSS satellite visibility from Genesis, we explore the possibility to take benefit from Genesis GNSS observations to remotely sense the ionosphere and the plasmasphere using the radio-occultation technique.