Ground truthing and calibration of imagery obtained using unmanned aerial systems (UASs - also known as UAVs or drones)
The use of unmanned aerial systems (UASs) is growing rapidly in the field of remote sensing as a new and versatile tool for data acquisition in areas such as agricultural resource monitoring, soil characterization, and environmental monitoring. Specific examples where sensors mounted on UASs have provided useful results include water stress detection in agricultural crops, plant biomass and nitrogen content in crops and grasses, yield forecasting for crops like wheat and rice, rangeland management, leaf area index, NDVI and vineyard management.
UASs fill the gap between satellite imagery and ground-based spectroradiometers. One of the main benefits is that their low operating height enables the generation of very high spatial resolution imagery data for small areas, with some systems reaching resolutions of 1 cm per pixel. UASs also can have a shorter revisit period than satellite platforms and offer high temporal resolution and increased maneuverability to allow access to previously inaccessible areas or hazardous environments. Another benefit of UASs is the low operational costs compared with other methods.