基于掩星数据的全球电离层地图精度评估  

Accuracy assessment of global ionospheric maps based on occultation data

作　　者：杨军 YANG Jun(Sanhe Digital Surveying and Geographic Information Technology Company Limited,Tianshui,Gansu 741000,China)

机构地区：[1]三和数码测绘地理信息技术有限公司,甘肃天水741000

出　　处：《北京测绘》2024年第8期1112-1116,共5页Beijing Surveying and Mapping

摘　　要：全球电离层地图数据被广泛应用于电离层的研究中,其精度评估对于研究电离层的性质、提高定位精度具有重要意义。为了评估全球电离层地图的精度,本文基于美国大学大气研究联盟提供的ionPrf产品,计算2008年和2012年的电离层和气候卫星联合观测系统(COSMIC)垂直总电子含量(VTEC)。本文通过直方图统计、纬度分布统计、年积日分布统计和地方时分布统计等方法,对国际全球导航卫星系统服务组织(IGS)全球电离层地图(GIM)的精度进行了评估。结果表明:(1)2008年的偏差平均值为5.09 TECU,2012年的偏差平均值为9.90 TECU;(2)2008年各纬度偏差介于3~8 TECU,2012年各纬度的偏差介于6~16 TECU;(3)偏差平均值在1月取得最大值,在夏至与秋分中间取得最小值;(4)2008年各地方时的偏差介于3~7 TECU,2012年各地方时的偏差介于6~14 TECU;(5)在太阳活动高年,偏差体现出赤道异常、半年度异常和冬季异常特征。综上所述,全球电离层地图的精度与太阳活动、地理位置、季节变化、日变化密切相关。global ionospheric map(GIM)data are widely used in research on the ionosphere,and its accuracy assessment is of great significance for studying the nature of the ionosphere and improving positioning accuracy.In order to assess the accuracy of the GIM,this paper calculated the constellation observing system for meteorology,ionosphere and climate(COSMIC)and vertical total electron content(VTEC)in 2008 and 2012 based on the ionPrf product provided by the University Corporation for Atmospheric Research(UCAR).The accuracy of GIM from the International Global Navigation Satellite System Service(IGS)was evaluated by histogram statistics,latitude distribution statistics,annual cumulative day distribution statistics,and local time distribution statistics.The results show that:①The mean of bias is 5.09 TECU in 2008 and 9.90 TECU in 2012;②The bias of each latitude in 2008 ranges from 3 to 8 TECU,and that in 2012 ranges from 6 to 16 TECU;③The mean of bias achieves its maximum value in January and its minimum value between the summer solstice and the fall equinox;④The bias of each local time in 2008 ranges from 3 to 7 TECU,and that in 2012 ranges from 6 to 14 TECU;⑤In years with high solar activity,the bias reflects equatorial anomalies,semi-annual anomalies,and winter anomalies.In summary,the accuracy of the GIM is closely related to solar activity,geographic location,seasonal variations,and daily variations.

关 键 词：电离层 总电子含量(TEC) 无线电掩星 全球电离层地图(GIM) 精度评估 

分 类 号：P228[天文地球—大地测量学与测量工程]