GNSS电离层模型改正精度评估与分析

Correction Accuracy Evaluation and Analysis for GNSS Ionosphere Model

电离层时延误差是导航定位信号在空间传播路径上的主要误差源之一,因此全面了解GNSS电离层模型的改正精度具有一定现实意义.根据GPS,BDS和Galileo系统所采用的电离层修正模型,利用2014年电离层校正参数,以高精度全球电离层图为基准,评估分析了三大系统电离层时延的改正精度.结果表明：目前GNSS使用的几种电离层修正模型的改正率在65%~75%左右;Galileo系统使用的第二版NeQuick模型与第一版NeQuick模型相比在修正精度上并无显著提高;GPS使用的Klobuchar 8参数模型在北半球25°一45°N的中纬度地区精度很高,但是在全球其他区域精度较低,分布性较差,而NeQuick模型全球改正率分布则较为平均且平滑.

Ionospheric delay is one of the major error sources for navigation signal in its propagation path. Therefore, the understanding of the GNSS ionosphere model correction accuracy has a practical significance. In this paper, ionosphere correction models are introduced. With high precision global ionospheric maps as a benchmark and the ionospheric correction parameters in 2014, the correction accuracy of the three systems ionospheric delay is evaluation and analyzed. It is found that the correction rates of several current GNSS ionospheric correction model have reached about 65% to 75%. Through comparison of the second edition NeQuick model and the first edition NeQuick model which Galileo system used, it is found that there is no significant improvement in accuracy. GPS Klobuchar eight parameters model has a high precision at 25°--45°N in the northern hemisphere mid- latitudes, but it has a poor distribution and lower accuracy in other regions of the world. However,NeQuick model global correction rate distributions are more even and smooth than those of the other models.