基于中国部分城市气象条件的对流层延迟分析

Tropospheric Delay Analysis Based on Some Chinese Cities' Meteorologic Conditions

随着用户对卫星定位导航精度要求的提高,对流层大气延迟影响将更加明显,需要进行延迟改正.对比分析了对流层大气延迟理论的主要映射函数模型,讨论了我国部分测站NMF(Niell Mapping Function)、VMF1(Vienna Mapping Function 1)和GMF(Global Mapping Function)的静力学映射函数和湿映射函数的分布情况,分别采用上述3种映射函数研究了我国部分城市气象条件下的对流层延迟.从运算结果分布曲线可知,所选测站的VMF1和GMF静力学映射函数曲线呈年周期余弦分布且大致相同,而NMF静力学映射函数值总体大于前两者;VMF1湿映射函数受气候变化影响较大,呈近似余弦函数分布,且VMF1和GMF呈近似夏季最小、冬季最大的分布.10°高度角下,所选测站斜延迟均呈现年周期余弦曲线分布,随着纬度的增加,斜延迟呈减小趋势,且呈夏季最大、冬季最小的分布,最大、最小值差约为2 m.

With the increase of the users＇ precision in satellite orientation and naviga- tion, the influence of the tropospheric delay has become increasingly vital, which needs to be corrected. The paper contrastively analyzes some main mapping functions＇ models of the tropospheric delay theory. It discusses the distributions of the hydrostatic/wet mapping functions of Niell Mapping Function （NMF）, Vienna Mapping Function 1 （VMF1）, and Global Mapping Yhnction （GMF）. And it analyzes tropospheric delay based on the meteo- rologic conditions in some Chinese cities. It could be concluded from the results that the hydrostatic VMF1 and GMF are in yearly periodic cosine distributions and approximately identical, whereas the hydrostatic NMF is roughly larger than the formers. The wet VMF1, which is influenced greatly by the atmosphere, displays close to cosine functions. Besides, VMF1 and GMF roughly display minimum in summer and maximum in winter, respectively. While the elevation angle is 10 degrees, the Slant Propagation Delays （SPDs） of the chosen stations are all in yearly periodic cosine distributions, and they decrease with the increase of the latitude. The SPD reaches maximum in summer and minimum in winter, and the difference is about 2 m.