地基GNSS区域电离层延迟实时格网算法研究

Real-Time Grid Algorithm Study of Ground-Based GNSS Regional Ionospheric Delay

采用中国区域陆态网络跟踪站的GNSS数据,利用载波相位平滑后的组合伪距观测值提取电离层延迟,扣除由CODE产品确定的卫星硬件延迟,利用半变异函数确定VTEC的空间相关性以及由经验值确定的时间相关性,建立VTEC和接收机DCB的随机模型,实现区域电离层实时格网建模。结果表明,模型99.7%的残差分布在1m以内,内符合精度约0.3m。以IGS电离层GIM为参考,格网点VTEC周日变化特征与之符合较好。接收机硬件延迟比较稳定,日变化量在1.5ns以内;利用IGS卫星硬件延迟和球谐系数,从原始观测信息中分离出区域测站接收机硬件延迟,以此为参考,周日均值较差在2ns以内。

Based on GNSS data from the crustal movement observation network of China（CMONOC）,we extract ionospheric delay from levelled carrier-phase observations,deduct the satellite hardware delay,then attach stochastic models of VTEC and DCB;these apply the semi-variable function as the spatial constraint of VTEC and the experienced VTEC and receiver hardware delay as the periods constraint,thus setting up the regional ionospheric grid model in real time.The results show that the inner precision of the model is about 0.3mand the residuals are within 1m.Taking GIM,which is the IGS ionospheric delay product,as reference,the characteristics of sequence diagram of VTEC are in accordance with GIM for a week.Furthermore,receiver hardware delay,with variations within 1.5ns each day,are relatively stable.Compared with the regional station receiver hardware delay isolated from the original observation by using satellite hardware delay and spherical harmonic coefficient of IGS,the mean differences for a week are all within 2ns.