A method for retrieving soil moisture from GNSS-R by using experiment data  

作　　者：毛克彪 Ma Ying Shen Xinyi Xia Lang Tian Shiying Han Jiaqi Liu Qing 

机构地区：[1]National Hulunber Grassland Ecosystem Observation and Research Station,Institute of Agricultural Resources and Regional Planning,Chinese Academy of Agricultural Sciences [2]International Agricultural Big Data and Nutrition Research Institute in China [3]State Key Laboratory of Remote Sensing Science,Jointly Sponsored by Institute of Remote Sensing and Digital Earth,Chinese Academy of Sciences and Beijing Normal University [4]Hydrometeorology and Remote Sensing Laboratory,The University of Oklahoma

出　　处：《High Technology Letters》2015年第2期219-223,共5页高技术通讯（英文版）

基　　金：Supported by the National Key Basic Research Program of China(No.2010CB951503,2013BAC03B00)

摘　　要：Soil moisture is a key parameter in agricultural irrigation. The L band（1.58GHz） on board global position system （GPS） satellite is well suited for monitoring the change of soil moisture. In order to investigate the potential of retrieving soil moisture using the L-band GPS bistatic radar, this paper analyzed a retrieval method by using field experiment data. In order to investigate the relation- ship between the soil moisture （ corresponding roughly to the 0 - 5cm top soil layer） and the signal- to-noise ratio （PT-S-R） to the direct GPS signal-to-noise ratio （Pd_sNR）, an experiment was conducted in Hulunber grassland of China in 2009 and 2011. Six field sites in the soil moisture experiment were utilized to analyze the relationship between soil moisture and the ratio of Pr-SNR to Pd-SN~ and the square of correlation coefficient was about 0.9 when the surface type was known and the elevation angle of the satellite ranged from 65 to 85 degrees approximately. The analysis shows that ratio of Pr-SNR to Pd-SNR can be used to monitor the soil moisture, because the ratio of Pr-SVR to Pd-SNR maxi- mized the elimination of the influence of different signals from different GPS satellites. The estimation accuracy could be improved if we make full use of the empirical knowledge on elevation angles of GPS satellites and ground roughness of different surface types.Soil moisture is a key parameter in agricultural irrigation.The L band（1.58GHz）on board global position system（GPS） satellite is well suited for monitoring the change of soil moisture.In order to investigate the potential of retrieving soil moisture using the L-band GPS bistatic radar,this paper analyzed a retrieval method by using field experiment data.In order to investigate the relationship between the soil moisture（corresponding roughly to the 05cm top soil layer） and the signalto-noise ratio(Pr-SNR) to the direct GPS signal-to-noise ratio(Pd-SNR),an experiment was conducted in Hulunber grassland of China in 2009 and 2011.Six field sites in the soil moisture experiment were utilized to analyze the relationship between soil moisture and the ratio of Pr-SNR to Pd-SNR and the square of correlation coefficient was about 0.9 when the surface type was known and the elevation angle of the satellite ranged from 65 to 85 degrees approximately.The analysis shows that ratio of Pr-SNR to P（d-SNR） can be used to monitor the soil moisture,because the ratio of P（r-SNR） to P（d-SNR） maximized the elimination of the influence of different signals from different GPS satellites.The estimation accuracy could be improved if we make full use of the empirical knowledge on elevation angles of GPS satellites and ground roughness of different surface types.

关 键 词：soil moisture global position system （ GPS） global navigation satellite system-reflection （GNSS-R） 

分 类 号：S152.7[农业科学—土壤学] P228.4[农业科学—农业基础科学]