实时电离层格网数据精度评估

Assessment of Ionospheric Real-time Data

电离层延迟是制约单频接收机定位精度的重要误差源之一.为提高单频接收机的实时电离层改正精度,需要实时电离层数据.以中国科学院空天信息创新研究院提供的实时电离层数据为例,对比分析不同太阳活动期实时电离层数据及预报电离层数据与IGS最终电离层数据之间的差值以及不同太阳活动期、不同纬度测站的电离层数据对电离层延迟进行改正后得到的定位精度.结果表明:在低太阳活动期和高太阳活动期,实时电离层数据无法很好地反映大部分海洋上空的电离层变化特性;对不同太阳活动期,实时电离层数据在高纬度测站的定位精度优于预报数据和广播模型,在中纬度测站的定位精度略低于预报数据而与广播模型定位精度相当,在低纬度测站的定位精度略优于预报数据和广播模型.

Ionospheric delay is one of the major error sources for single-frequency receivers.To improve the accuracy of ionospheric corrections in real-time,some Ionosphere Associate Analysis Centers started to provide real-time global ionospheric data.However,the accuracy of them is unknown.In this sense,this study takes the real-time ionospheric data provided by Aerospace Information Research Institute,Chinese Academy of Sciences(CAS)as an example for assessment.First,the differences between different kinds of ionospheric data are calculated.Meanwhile,positioning accuracy corrected by real-time ionospheric data and ionospheric broadcast ionospheric model over different latitudes for different solar activity periods is presented.The experimental results show that the real-time ionospheric data cannot reflect the spatial variation over the oceanic region for the experimental period.The positioning accuracy corrected by real-time ionospheric data is better than that by ionospheric predicted products and Klobuchar model for high-latitude stations.However,the positioning accuracy corrected by real-time ionospheric data is a bit worse than that of Klobuchar model for mid-latitude stations,while it is better than that corrected by ionospheric predicted products and Klobuchar model for low-latitude stations.