Next Article in Journal
Mapping Chestnut Stands Using Bi-Temporal VHR Data
Next Article in Special Issue
Precise Orbit Determination for BeiDou GEO/IGSO Satellites during Orbit Maneuvering with Pseudo-Stochastic Pulses
Previous Article in Journal
Assessing the Impact of Satellite Revisit Rate on Estimation of Corn Phenological Transition Timing through Shape Model Fitting
Previous Article in Special Issue
A Strategy to Mitigate the Ionospheric Scintillation Effects on BDS Precise Point Positioning: Cycle-Slip Threshold Model
Open AccessLetter

Soil Moisture Estimation by GNSS Multipath Signal

School of Geodesy and Geomatics, Wuhan University, Wuhan 430079, China
Key Laboratory of Geospace Environment and Geodesy, Ministry of Education, Wuhan 430079, China
School of Environmental Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, China
Chongqing Meteorological Bureau, Chongqing 401147, China
Author to whom correspondence should be addressed.
Remote Sens. 2019, 11(21), 2559;
Received: 26 September 2019 / Revised: 28 October 2019 / Accepted: 30 October 2019 / Published: 31 October 2019
(This article belongs to the Special Issue Global Navigation Satellite Systems for Earth Observing System)
Global navigation satellite system (GNSS) multipath signals received by a geodetic-quality GNSS receiver can be used to estimate the water content of soil around the antenna. The direct signals from satellite to GNSS antenna are the most valuable signals in geodetic measurement, such as positioning, navigation, GNSS control network, deformation monitoring, and so on. However, the GNSS antenna also captures the reflected signals from the ground, which contain information of surrounding environment, so that useful information about the reflection surface can be inferred by analyzing the reflected signal. This technique is termed as GNSS-interferometric reflectometry. The signal-to-noise ratio (SNR) data recorded by a receiver contains SNR component of reflected signals, which is related to the soil moisture of the ground. The changes of soil moisture content will cause the change of soil permittivity and reflectivity which are the key factors that make further change of the SNR of reflected signals. We used the measured data to evaluate the correlation between amplitude of multipath induced SNR time series and real soil moisture. An improved soil moisture estimation algorithm based on multipath induced SNR amplitude data is proposed in this paper. The performance of the proposed soil moisture estimation method is evaluated using the 15-month data recorded by PBO H2O GNSS station and a 14-day experiment in Wuhan, China. The experimental results show that the estimated soil moisture has a strong correlation with the real soil moisture and the estimation accuracy in terms of root-mean-square error (RMSE) is 0.0345 cm3cm−3 and 0.0339 cm3cm−3, respectively. Meanwhile, the application scope of the method is given. View Full-Text
Keywords: GNSS reflectometry; soil moisture; SNR time series; median filter; parabolic fitting GNSS reflectometry; soil moisture; SNR time series; median filter; parabolic fitting
Show Figures

Graphical abstract

MDPI and ACS Style

Chang, X.; Jin, T.; Yu, K.; Li, Y.; Li, J.; Zhang, Q. Soil Moisture Estimation by GNSS Multipath Signal. Remote Sens. 2019, 11, 2559.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

Back to TopTop