Seminars

Radar images have the enviable advantage of being able to be acquired day or night, regardless of weather conditions. However, despite this remarkable advantage, they have long had an intimidating reputation—their sometimes counterintuitive geometry, their particular acquisition mode, the presence of speckle, their advanced modes such as polarimetry, interferometry, etc., have given many analysts the impression that they are a world reserved for insiders. Historically developed in a primarily military context, radar imaging has gradually evolved towards civilian and environmental uses, boosted by the advent of major satellite missions such as Sentinel-1, Biomass, and NiSAR, as well as by the emergence of commercial players offering unprecedented resolutions (Capella, ICEYE, Umbra). This seminar will begin with a brief historical overview of the evolution of radar imaging and Onera’s fundamental contributions in this field. It will then clarify the physical and geometric principles that fundamentally distinguish a radar image from an optical image, in order to better understand the key applications where this technology is becoming indispensable —monitoring of forest environments, the cryosphere, ground deformation tracking, natural risk management, among others—as well as the scientific challenges that remain in order to make the best use of these images. Finally, particular attention will be paid to the rise of radar time series, which are now at the heart of research efforts due to their unprecedented potential for the detailed characterization of dynamic processes on the Earth’s surface.

Presentation of new acquisition possibilities offered by drones, as well as the miniaturization of sensors (LiDAR and others) in environmental studies. Topics covered will include regulations, equipment (flying and ground-based drones), sensors, and, most importantly, possible data processing methods.

Faced with environmental challenges, the ministry responsible for ecological transition is relying on satellite applications to strengthen the monitoring, evaluation and effectiveness of public action. The 2023-2027 Satellite Applications Plan (PAS) aims to facilitate the operational use of data from Earth observation satellites by government agencies, operators and local authorities. This presentation sheds light on the objectives, practical uses and challenges of this public initiative.