Proof-of-Concept of Direct-to-Satellite IoT for Earth Observation Applications: Soil Moisture Experiment. - Joan Adrià Ruiz-de-Azua; Joan Pagès; Carlos Labella; Pol Delgado; Marisa Catalan; Manel Medina; Josep Paradells; Pol Guixé; Sergi Figuerola; José Antonio Jara; Agnès Lladós; Julià Talaya; et al. (IGARSS, 2022)