High Spatial Resolution Soil Moisture Mapping using S2-SMM System

Abstract:

The S2-SMM (Soil Moisture Mapping) system makes use of a Lobe Differencing Correlation Radiometer (LDCR) integrated into a small unmanned aerial system (UAS) to provide a capability to measure soil moisture at high spatial resolution for a range of scientific and operational purposes, including satellite data validation, precision agriculture, and evaporation and transpiration studies of boundary layer heat transport. Compared with other methods based on either in-situ measurements or existing airborne sensors suitable for manned aircraft deployment, the integrated design of the LDCR on a lightweight UAS can provide sub-watershed (~km scale) coverage at a spatial resolution as high as ~15 m with low instrument and operation cost. Flight tests using S1-SMM were performed at the Canton, Oklahoma Soilscape site in September 2015 and Irrigation Research Foundation (IRF) in Yuma Colorado in June 2016 to demonstrate system performance. The S2-SMM is using a newer version of L-band radiometer and UAS system, which has tight integration of the sensor with the UAS avionics and airframe enables precision flight control for low altitude missions permitting the sensor to accurately map soil moisture. The newly added digital correlator will make the detection and mitigation of radio frequency interference (RFI) from the environment possible. Meanwhile, a multi-spectrum camera is used to map high spatial resolution ancillary data for the soil moisture retrieval. The developments of the latest hardware system, field campaign, semi-real time ancillary data process and soil moisture retrieval will be demonstrated along with intercomparisons with in-situ data.