摘要
电离层是大气层中的一个电离区域 ,高度范围大约在 60～ 1 0 0 0km。电磁波信号穿越电离层时其传播速度会发生变化 ,传播路径也会略微发生弯曲 ,从而使信号的传播时间乘以在真空中的光速不等于信号源至测站的几何距离。对VLBI观测来讲 ,电离层引起的差异可达近百米。文中从电磁波的传播原理出发 ,讨论了信号传播速度和传播路径变化引起的VLBI观测延迟 ;对目前采用的各种电离层延迟模型进行了分析总结 ;
Ionosphere is an ionized area in the atmosphere with height from 60 ～ 1000 km. When electromagnetic wave signals traverse the ionosphere, its transmitting velocity will change and its transmitting path will curve. Consequently, the transmitting delay of signals multiplied by the velocity of light in the vacuum is not equal to the geometric distance between the signal source and the site on the ground. As to VLBI observations, the errors derived from ionosphere refraction can attain to 100 meters. In this paper, on the basis of the transmitting principle of electromagnetic wave the VLBI observation delay derived from the transmitting velocity and path of signals has been discussed. The models of multifarious ionosphere refraction delays has also been analyzed and summed up. We proposed that the VLBI observation with single frequency should consider the influence of high order items and the curve of path or make use of the area correction model of ionosphere delay.
出处
《测绘学院学报》
北大核心
2003年第1期14-17,21,共5页
Journal of Institute of Surveying and Mapping
基金
国家自然科学基金 ( 4 0 1740 0 2 )
国家杰出青年科学基金 ( 4 0 12 5 0 13 )资助
