Galileo长基线定位中四频电离层延迟改正方法分析

Analysis of four-frequency ionospheric delay correction method in Galileo long-baseline positioning

针对电离层延迟会对长基线定位精度造成影响的问题,提出一种采用Galileo四频信号的四频弱电离层组合方法,通过构造弱电离层相位组合观测值建立定位方程,进而采用最小二乘平差方法实现弱电离层组合模糊度和三维基线坐标参数的解算。采用Galileo四频数据对比分析了四频IR组合方法和基于FCAR模型的电离层延迟参数估计方法的长基线定位精度,实验结果表明,当基线长度超过500 km时,四频IR组合方法在水平和垂直方向的定位精度均可达到dm级,相较于电离层延迟参数估计方法,可以有效改善水平和垂直方向的定位结果,定位精度提升幅度可分别达到15%和30%以上。相对定位精度达到1×10^(-9)m,满足高精度相对定位要求。

Aiming at the problem that the ionospheric delay will affect the long-baseline positioning accuracy,this paper proposes a four-frequency ionosphere-reduced combination method using the Galileo four-frequency signal.The positioning equation is established by constructing the ionosphere-reduced phase combined observations,and then the least squares adjustment method is used to calculate the ionosphere-reduced combined ambiguity and three-dimensional coordinate parameters.The long-baseline positioning accuracy of the four-frequency IR combination method and the ionospheric delay parameter estimation method based on the FCAR model is compared and analyzed using Galileo four-frequency data.The experimental results show that when the baseline length exceeds 500 km,the positioning accuracy of four-frequency IR combination method can reach the decimeter level in the horizontal and vertical directions.Compared with the ionospheric delay parameter estimation method,it can effectively improve the positioning results in the horizontal and vertical directions,and the positioning accuracy can be improved by more than 15%and more than 30%respectively.The relative positioning accuracy reaches 1×10^(-9) m,which meets the requirements of high-precision relative positioning.