利用GPS-IR监测土壤含水量的反演模型

Retrieval Model for Soil Moisture Content Using GPS-Interferometric Reflectometry

摘要: GPS-IR（GPS-interferometric reflectometry）本质上是一种基于GPS辐射源的双基地雷达技术，利用大地测量型接收机记录的信噪比（signal-to-noise ratio，SNR）数据可用于反演土壤含水量。针对GPS-IR获取土壤含水量的参数估计问题，提出了一种改进的反射信号参数估计方法，并研究了土壤含水量反演模型的建立过程。实验结果表明，利用改进的反射信号参数估计方法可获得更加准确可靠的结果，反射信号相位与土壤含水量间存在显著的线性相关，可建立土壤含水量的线性反演模型，但在连续降雨条件下会存在较大误差。

Abstract: GPS-interferometric reflectometry can be used to infer temporal changes in near surface, soil moisture content. To estimate reliable GPS interferogram metrics such as phase and amplitude, an improved estimation method based on the GPS signal-to-noise ratio (SNR) data is presented, and a retrieval model for soil moisture content is constructed. Experiments indicate that the improved method is capable of estimating accurate and reliable GPS interferogram metrics as compared to the common method. The SNR phase shows a nearly linear relationship to the soil moisture content. Furthermore, a linear retrieval model for soil moisture content can be achieved, and the model is sensitive to consecutive precipitation.