GNSS-I/MR河流边界及水位测量理论与仿真

Theories and simulations of river boundary and level measurement using GNSS-I/MR

从几何构型和理论模型2个角度探究全球导航卫星系统干涉/多径反射测量(GNSS-I/MR)技术提取河流边界和测量河流水位的可行性。基于河流/河岸介电常数的差异性和河岸相对于河流存在斜度的事实,定义对河流边界敏感的反-直比和实验变化率2个观测量。在希尔伯特变换估计的载噪比包络和相位的基础上,提出基于一元二次方程求解反-直比和线性拟合实验变化率的估计方法,以及3-阈值最大类间方差识别河流/河岸和循环拟合提取河流边界的方法。基于河流表面的实验变化率测量河流水位,通过搭建仿真平台和设计2种河流场景,仿真验证所提方法的有效性。仿真结果表明:在设定参数下,利用介电常数检测场景1和场景2河流边界的均方根误差分别为1.47 m和1.13 m;实验变化率检测场景1和场景2河流边界的均方根误差分别为0.49 m和0.35 m;场景1和场景2的测量高度和真实值的误差分别为0.09 m和0.13 m。

This paper explored the feasibility of extracting the river boundary and measuring the river level using global navigation satellite system-interferometric/multipath reflectometry(GNSS-I/MR)from its geometry and theoretical models.Based on the difference in the dielectric constant between the bank and river and the fact that the bank has a slope relative to the river,two observational variables sensitive to river boundary,namely the reflected-to-direct ratio and the delay rate were defined.According to the estimated envelope and phase of carrier-to-noise ratio using Hilbert transform,this paper proposed the estimation method of the reflected-to-direct ratio based on a univariate quadratic equation and that of the delay rate based on linear fitting,as well as a 3-threshold maximum interclass variance-based algorithm to recognize river/bank and a looped fitting-based algorithm to extract the river boundary.The river level was measured based on the delay rate of the river surface.By setting up a simulation platform and designing two river scenarios,the effectiveness of the proposed method was verified through simulation.