Low cost sensor for soil moisture estimation using GNSS reflectometry

Abstract

This Thesis is on the development of low-cost sensors for soil moisture estimation using Global Navigation Satellite System (GNSS) reflectometry. Traditional soil moisture sensing methods are often expensive and invasive, and GNSS reflectometry has the potential for large-scale soil moisture sensing due to the availability of GNSS infrastructure and the low-power and low-cost GNSS receivers. Several studies have demonstrated the feasibility and effectiveness of GNSS reflectometry for soil moisture estimation using low-cost sensors. The development of low-cost GNSS reflectometry sensors can greatly improve the accessibility and affordability of soil moisture sensing for farmers and environmental researchers, and facilitate the deployment of large-scale soil moisture monitoring networks. This Thesis reviews the state of the art in low-cost GNSS reflectometry sensors for soil moisture estimation, including their design, implementation, and performance evaluation. The potential applications and future research directions for low-cost GNSS reflectometry sensors are also discussed. Data for our study were collected using our raspberry-pi-based GNSS receivers. Additionally, we used sample data from IGS station and MFLE, PBO data wherever comparison was necessary. Keywords: GNSS reflectometry; Soil moisture; SNR time series; Sinusoidal fitting; GNSS Toolbox