基于GNSS-R的煤矿区复垦地土壤湿度反演

Inversion of Soil Moisture of Reclaimed Land in Coal Mine Area Based on GNSS-R

为研究煤矿区复垦地土壤湿度快速有效的监测方法,以安徽省淮南矿区煤矸石充填复垦地为研究对象,利用GNSS-R技术反演其土壤湿度,分析了GPS卫星反射信号的干涉特征参量与土壤湿度参考值的相关性关系,采用线性、指数回归建立基于GPS卫星L1、L2波段的单波段反演模型和L1-L2双波段协同反演模型,并验证模型精度。结果表明,振幅与土壤湿度参考值的相关程度高于相位和频率,其最大相关系数为0.6614;相比于单波段反演模型,L1-L2双波段协同反演模型精度较高,其线性模型为最优反演模型,且R 2为0.8784,RMSE为0.1297%,最大相对误差为0.0261%,平均绝对误差为0.1140%,表明L1-L2双波段协同反演模型在地表5cm内的反演效果较好,可用于煤矿区复垦地土壤湿度的快速监测。

To study rapid and effective monitoring method of soil moisture in reclamation of coal mine area,the gangue filling reclamation area in Huainan mining area in Anhui Province was taken as the research object,and the soil moisture was retrieved by using Global Navigation Satellite System-Reflectometry(GNSS-R)technology,and the correlation is analyzed between the interference characteristic parameters of the GPS satellite reflection signal and the soil moisture reference value.The single-band inversion models based on GPS satellites L1 and L2 bands and a L1-L2 dual-band cooperative inversion model are established with linear and exponential regression used,and their accuracy verified too.The results show that the correlation between amplitude and reference value of soil moisture is higher than that of phase and frequency,and its maximum correlation coefficient is 0.6614.Compared with the single-band inversion model,the L1-L2 dual-band cooperative inversion model has a higher accuracy,and the linear model is the optimal inversion model.The validation model R 2 is 0.8784,RMSE 0.1297%,the maximum relative error 0.0261%,and the average absolute error 0.1140%,which shows that the L1-L2 dual-band cooperative inversion model has a better inversion effect within 5cm of the ground surface,and is able to be used in rapid monitoring of soil moisture reclamation land in coal mine area.