Key to Black Swift’s Soil Moisture Mapping solution is the unique L-band radiometer developed and tested under NASA’s SBIR (Small Business Innovation Research) program. Unlike thermal imaging modeling, which focuses on plant stress resistance, this passive microwave radiometer provides full coverage soil moisture measurements, even under dense canopy crops, mapping up to 600 acres per flight. The Black Swift S2 equipped with this radiometer has documented datasets that correlate with in situ probes, yet on a scale stationary sensors cannot effectively achieve.
While NASA’s Soil Moisture Active Passive (SMAP) satellite, can provide soil moisture data on a regional level (watershed, county, state, etc.), its kilometer level resolution has proven insufficient for use by individual farmers. Supplementing satellite images with high resolution, low altitude measurements would greatly improve NASA’s ability to monitor soil moisture while providing invaluable data for those engaged in optimizing agricultural yields.
This technology was developed as part of the NASA Small Business Innovation Research (SBIR) program. Using the soil moisture mapping UAS, NASA scientists can gather low altitude measurements from the on-board L-band radiometer with a higher revisit frequency. This can greatly improve satellite calibration by providing localized, high resolution data of areas of interest.
The soil moisture UAS solution consists of the S2 airframe, avionics, radiometer, and supporting sensors specifically designed for the task of accurately measuring soil moisture content, even under dense canopy crops. The primary instrument is a passive microwave radiometer that provides full coverage soil moisture measurements over an area of up to 600 acres per flight. Tight integration of the sensor with the avionics and airframe will enable precise flight control for low altitude missions in the range of 15m-30m above ground level (AGL) required for the sensor to accurately map soil moisture down to ~5cm in depth at up to a 15m resolution.
At the core of the system is the S2 airframe and SwiftCore flight management system. The pair provides a highly capable UAS platform specifically designed to accommodate the next generation of scientific payloads. It has passed NASA’s rigorous flight safety review, and contains a level of autonomy and redundancy to ensure data collection can be done routinely and safely. The aircraft limits electromagnetic interference from sub-systems and is capable of low altitude, terrain following flight. In addition, the S2 is designed around a modular architecture, allowing rapid development to accommodate new instruments with the aircraft. Through this innovation, The Soil Moisture Company is able to rapidly develop solutions to meet the needs of the data gathering mission and each customer’s unique requirements.
Figure: Soil moisture map generated using the S2 UAS and radiometer payload over an instrumented test site (text indicates in-situ probe name and measured soil moisture content).
By mapping soil moisture in a region impacted by severe flooding, data obtained could provide alerts and warnings to areas susceptible to flash flooding. Black Swift’s Soil Moisture Mapping could provide this data at a fraction of the cost of satellite-based sensing, improving predictions for flooding events in vulnerable watersheds around the country.