A Simulation Study of Volumetric Soil Moisture Evaluation Using NavIC–IR

The sensitivity of the reflectivity of microwave signals to the moisture content of the soil makes it possible for soil moisture evaluation by remote sensing. L5 band signals used by the Indian regional navigation satellite system NavIC can be utilized as signals of opportunity to remotely assess soil moisture. Depending on the amount of water in the soil, the amplitude and phase of these signals alter when they reflect off the ground. As the satellite moves in the sky, a sinusoidal interference pattern is created when the reflected signals combine with the direct signals from it. This is known as NavIC–interferometry/reflectometry or NavIC-IR. The present work is a detailed theoretical simulation of the above-mentioned interference process using a stratified multilayer soil model. The simulation results are in good agreement with the previously reported experimental results by other groups in India using NavIC signals. There is a linear dependence between the phase of the interference pattern and the volumetric soil moisture, which is in good agreement with the previous empirical experimental findings.