5550 20220111104829.0 10.1109/EFTF/IFCS52194.2021.9604250 DOI SCART-2022-0014 Bertrand, Bruno GAlileo Survey of Transient Objects Network (GASTON) Project: Searching Dark Matter using the Galileo Satellites 2021 Some models for Dark Matter (DM) suggest possible encounters with a period τ of macroscopic dark structures with the Earth, implying transient signatures on clocks onboard GNSS satellites. In this paper we first introduce the GASTON project, an original study dedicated to the search for such ‘DM transients’ using the network of passive H-Maser onboard Galileo satellites. This project is based on a 3-months measurements campaign carried out in the early 2021 where precise satellite clock measurements are supplemented by an intensive laser ranging (SLR) campaign on Galileo satellites. Then, we present preliminary results based on single satellite frequency jumps between consecutive 30s epochs over the 3 months campaign. In particular, we already bring strong constraints on the parameter space for transient DM objects from 10^5 to 10^9 km, a region which was never explored previously with GNSS clocks. H2020-ESA-038.10/ GASTON/ GASTON NO Global navigation satellite system GNSS Time-frequency analysis Dark Matter Defraigne, Pascale Sheremet, Alexandra Hees, Aurélien Wolf, Peter Delva, Pacôme Chabé, Julien Courde, Clément Mendes, Luis Ventura-Traveset, Javier Dilssner, Florian Schoenemann, Erik proceedings of the 2021 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS) 2021 bruno.bertrand@observatoire.be https://ieeexplore.ieee.org/document/9604250 published in REFERD