Experiments and Analysis of Soil Moisture Monitoring Based on GPS Signal-to-Noise Ratio Observables

Abstract

Effective monitoring of soil moisture is the basis of meteorological, agricultural and environmental scientific researches. Using the SNR observables to monitor the fluctuation of soil moisture is a new approach which does not suffer from destruction of environments, difficult data assimilation, limits of temporal-spatial resolutions and so on. However, it also has many issues need to be discussed deeper such as too less examples, the effective areas, the parameter setting and even how to describe and model the relationship between the SNR results and soil moisture from other measurement ways. In this paper, with measured GPS SNR observables and simulated soil water content data, the comparative experiment is carried out to discuss them. As is shown from the experiment process and results, this approach can effectively retrieve the soil water content. The effective area is within about 45 m around the antenna phase center. The exponential function can be used to described the correlation between the relative delay phase of SNR reflected signal and soil water content well. Meanwhile, selection of the advanced satellites and recording of the L2C observables would be prone to obtain the high quality SNR observables that lead to the more robust and accurate monitoring results.