An experimental validation method on GNSS signal attenuation model in soil

doi:10.11947/j.AGCS.2020.20200259

Abstract

Abstract: The attenuation of GNSS signals in soil is of great significance for the related research of using GNSS signals to measure soil moisture. In this paper, for the first time, the attenuation of BDS (BeiDou navigation satellite system) and GPS (global positioning system) signals in the soil was studied through experiments. In the experimental design, the GNSS antenna was placed into the soil, then the soil thickness and moisture above the antenna were continuously changed to collect the power attenuation data of the GNSS signal. Finally, these data were used to retrieve soil moisture in order to validate the GNSS signal attenuation model. Experimental results show that soil can significantly attenuate GNSS signals. The greater the soil moisture value and thickness value is, the more severe the attenuation is. In the case of clay type soil and soil moisture of 0.15~0.30 cm³/cm³, the GNSS signal power has been attenuated to be undetectable by the GNSS receiver when the soil thickness reaches 21 cm. Further retrieval of soil moisture based on the GNSS signal attenuation model was carried out, the results show that the attenuation model is more accurate when the soil thickness is larger than or equal to 10 cm and when the satellite elevation angle is larger than 50°. And under this situation, the root mean square error of soil moisture retrieval using BeiDou B1 signal and GPS L1 signal is less than 0.04 cm³/cm³ and 0.09 cm³/cm³, respectively.

Key words: soil moisture measurement, BDS, signal attenuation, carrier-to-noise ratio, effective remote sensing depth

CLC Number:

P237

HAN Mutian, YANG Yi, ZHANG Bo. An experimental validation method on GNSS signal attenuation model in soil[J]. Acta Geodaetica et Cartographica Sinica, 2020, 49(9): 1202-1212.

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