Analysis of Key Issues on GNSS-R Soil Moisture Retrieval Based on Different Antenna Patterns

Area of Science:

• Geosciences
• Remote Sensing
• Signal Processing

Background:

• Global Navigation Satellite System-Reflectometry (GNSS-R) is an emerging technique for soil moisture monitoring.
• Existing GNSS-R studies often lack comprehensive analysis of critical factors like reflection points, spatial resolution, and detection depth.

Purpose of the Study:

• To systematically and quantitatively determine the three-dimensional extent of soil moisture detection using GNSS-R.
• To provide theoretical analysis and formula derivation for understanding the key issues in GNSS-R soil moisture sensing.

Main Methods:

• Theoretical analysis and formula derivation to define specular reflection point, spatial resolution, and detection depth.
• Analysis of two application scenarios: ground-based GPS measurements and an airborne experiment.

Main Results:

• Quantitative determination of the sensing extent in three dimensions for GNSS-R soil moisture retrieval.
• Analysis of specular reflection points, Fresnel ellipse clusters, and sensing depth for ground-based and airborne data.
• Demonstration of spatial distribution and sensing depth for soil moisture estimation.

Conclusions:

• The study provides a comprehensive framework for understanding GNSS-R soil moisture sensing limitations and capabilities.
• Results offer valuable references for the development of BeiDou-R techniques for soil moisture remote sensing.