陆基GNSS反射信号河流水文多参数一体化反演研究

Chinese rivers have significant regional features and have frequent disasters. It is important to significantly measure the width, flow velocity, level and discharge of the river for the monitoring of Chinese climate change and disasters. At present, the mature way is contact way which is money- and material-consuming, and is unsuitable to be used for the complex case so that the hydrological data of a large number of the rivers are lacking. As an opportunity-source remote sensing, GNSS Reflectometry (GNSS-R) has the low-cost and -power advantage, and has been paid attention at home and abroad. Based on the shortcoming of existing way, this project aims to use GNSS-R to monitor the river parameters to expand the GNSS-R application in remotely sensing inland water. This project will explore the theory and method of measuring width, flow velocity, level and discharge of the river using GNSS-R, focus on: 1) the method of calibrating the uncertainty of the reflected GNSS signal link to accurately estimate reflectivity of land and river, and the monitoring method of river width/bound using time-series reflectivity; 2) retrieving the flow velocity using short-sequence spectrum estimation and the all-case method of retrieving the rivers level based on the scattering scene decision; 3) the method to compute the distribution of average velocity and water level in river section using spatial interpolation and the full-parameter model of estimating river discharge. In one word this project will be able to provide a low-cost, accurate and integrated way for the monitoring of the river.

我国河流有明显区域特征，且灾害频发。有效探测河流宽度、流速、水位及流量等参数对我国气候及灾害监测具有重要作用。目前接触式为主的探测在财力和物力上消耗巨大，且不宜在复杂场景应用，严重制约了河流水文参数的获取。GNSS反射信号作为一种机会源手段，具备低成本、低功耗等优势，已得到国内外重视。针对目前河流水文探测的现状，瞄准将GNSS反射信号用于河流监测，拓展GNSS反射信号在内陆水体遥感应用的科学目标，探索利用河流反射的GNSS信号探测河流宽度、流速、水位及流量的机理，重点研究：①信号链路不确定性校正的陆河反射率精确估计及基于反射率序列的河流宽度反演方法；②短时序谱估计的河流流速反演及场景判决的伪码/载波协同的覆盖不同场景的河流水位反演方法；③空间插值计算河流断面平均流速和水位分布的方法及全参数积分式河流流量估算模型，为河流监测开辟一种快速、低成本、一体化的遥感新手段。

我国河流有明显区域特征，且灾害频发。有效探测河流宽度、流速、水位及流量等参数对我国气候及灾害监测具有重要作用。目前接触式为主的探测在财力和物力上消耗巨大，且不宜在复杂场景应用，严重制约了河流水文参数的获取。GNSS反射信号作为一种机会源手段，具备低成本、低功耗等优势，已得到国内外重视。本项目针对目前河流水文探测的现状，瞄准将GNSS反射信号用于河流监测，拓展GNSS反射信号在内陆水体遥感应用的科学目标，从几何构型、理论模型、仿真验证及试验验证四个方面探索利用河流反射的GNSS信号探测河流边界/宽度、流速、水位及流量的机理，为河流监测开辟一种快速、低成本、一体化的遥感新手段。本项目结果表明：1）GNSS反射计技术可有效测量河流边界、水位及流速，进而测量河流流量；2）GNSS-IR技术可提取河流边界和测量河流水位，而无法测量河流流速；3）GNSS信号能够穿透河岸土壤表面，且河岸土壤湿度和穿透深度具有一定相关性，通过测量穿透深度，可测量河岸的土壤湿度；4）线极化的GNSS信号对河岸土壤湿度更敏感，在河流参数测量中潜力巨大。