The MISTRALE project proposes to address soils moisture management in agriculture as well as wetlands or flooded areas monitoring by using Global Navigation Satellite Systems reflected signals (GNSS-R) as a powerful technology for humidity or flooded mapping. The detection by GNSS-R is known to be much more reliable than visible/NIR imagery, and will be usable even under a cloud cover, during the night and even under vegetation (bushes, grass, trees) when passive remote sensing is not applicable. The main objective is to demonstrate a service chain in different use cases : pilot projects will be carried out in soil humidity mapping for agriculture (optimizing the water resource management), wetlands and flooded areas (risk management, flood-prone areas, damages evaluation). In order to meet the objectives, a GNSS-R receiver embedded into a small RPAS (Remotely Piloted Aircraft System) will be developed and implemented into an operational chain to provide the service. GNSS-R technology aims at measuring the GNSS signals reflected on the ground, and, compared to the direct signals, permits a measurement of the soil humidity (from 0 to 100%) as well as flooded extend. The use of GALILEO signals will significantly improve the precision of mapping. The operational system will integrate three main axes of development: adapting the GNSS-R technology for the requirements, making a compact GNSS-R receiver and optimizing an existing RPAS. Using EGNOS and GALILEO in the project will also improve navigation capabilities of small RPAS (<4Kg) and contribute to the development of regulations for their integration in airspace. We assembled a consortium that addresses all aspects of the project : four SME specialized in GNSS receivers, GNSS-R technology, operational applications and dissemination, two labs for RPAS and GNSS-R technology. An advisory board composed of agronomy and environment specialists as well as end users will complete the skills of the consortium.