Non Technical Summary
Scarcity of water and its criticality for agriculture is a topic of increasing urgency as pressures on this fundamental resource continue to grow. Knowledge of the soil moisture is key to informed irrigation practices, yet probes are expensive and sparse. Current Earth observation technologies provide coarse (multi-km) observations of just the upper surface (0-5cm). The root zone soil moisture (to ~0.5m depth) reflects much more adequately the water available for plant utilization in the immediate to near-term. This information at a high spatial resolution is highly pertinent for precision management at the plot-scale and can be tailored for individual crop needs.We will build a drone-based root- zone soil moisture mapping radar capable of autonomous operation with a coverage of ~8000 acres per hour at ~20m resolution. In the long term, we envision that these maps will be available to field managers via a near-real-time web-based application to allow timely decision making about irrigation and harvesting, and therefore achieving optimal yield while minimizing water usage.

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
111	0210	2020	100%

Knowledge Area
111 - Conservation and Efficient Use of Water;

Subject Of Investigation
0210 - Water resources;

Field Of Science
2020 - Engineering;

Goals / Objectives
Remote Sensing Solutions (RSS) is partnering with the University of Southern California to develop a drone-based root- zone soil moisture mapping radar capable of autonomous operation with a coverage of ~8000 acres per hour at ~20m resolution. This responds to the Water Quality and Conservation priority (ie. "Develop new and improved technologies to optimize water management conservation at both the farm level and at a watershed scale"). The innovation is a miniaturized radar utilizing RSS' state-of-the-art technology deployed on a drone. The radar operates at ~0.75m wavelength transmitting pulses which scatter from the underlying soil layers providing information about the root zone soil moisture. The radar will be able to frequently map soil moisture at the root zone, a capability which does not currently exist and has the potential to greatly improve water management practices and conservation for the agricultural industry.

Project Methods
The Phase 1 effort will conduct all the trades necessary to ensure that we have a detailed design that under a Phase 2 we can implement a prototype system. In performing this R&D effort we will begin with an established measurement requirements. These are the same requirements as set forth from a heritage NASA program. From that, we will use a full flow-down of requirements from measurement, to system, to subsystem, down to the component level where necessary. We will field the bench tested prototype unit on a portable tower to at an instrumented site to demonstrate the RZSM measurement, verify the end-to-end performance and verify RZSM trends that are correlated to the in situ data. We will scale the performance for the drone system. Furthermore, we will be able to demonstrate the sensor calibration and the stability of that calibration. The result is verification of the drone-based design which will be realized in Phase 2.