福爾摩沙衛星三號電離層全電子含量誤差分析與比較

Error analysis of Ionospheric TEC measure by using Formosat-3

黃建樺(Jian-Hua Huang)

指導教授 ： 朱延祥

國立中央大學/地球科學學院/太空科學研究所/碩士(2012年)

摘要

本論文的主要內容分兩部分：1.探討福爾摩沙衛星三號衛星掩星法的比較。2.衛星掩星法所反掩的全電子含量與真實資料誤差分析與比較。衛星掩星法比較的部分使用了2008年Ionphs資料，對於校正TEC(Calibration TEC)的計算時，有輔助面與無輔助面分別有兩種不同的演算方式，本論文藉由兩不同方式所求得的電子濃度對大值資料，再與電離層探測儀(Ionosonde)比較，發現使用輔助面反掩的電子濃度資料與不使用輔助面反掩的資料差不多，因此無輔助面的掩星資料仍具有可信度。全電子含量部分，為了取得真實量測的資料，使用了2008年到2010年COSMIC PodTEC資料，以及IGS所提供的電離層地圖(IONEX)資料；由IONEX可以得到地表至GPS高度全電子含量，COSMIC PodTEC 提供了低軌道衛星到GPS之間的全電子含量，將此連線資料投影到低軌道衛星正上方後，兩資料相減得到地表到低軌道衛星全電子含量，再去與COSMIC Ionprf的全電子含量比較；比較結果發現兩者斜率及相關係數上有良好的相關性，白天的相關係數會優於晚上；磁緯度比較方面，發現COSMIC Ionprf的TEC，白天在低緯度地區(±30度)，Ionprf有低估的現象，誤差百分比約為20%，在中緯度地區(30~60度)，Ionprf有高估的現象，誤差百分比約為-20%，晚上大部分為-20%的低估。

關鍵字

福爾摩沙衛星三號 ； 全電子含量 ； 電離層

並列摘要

The main content is divided into two parts in this
paper: 1. The comparison between occultation methods in
the FORMOSAT-3/COSMIC satellites. 2. Total Electron Content
data error analysis as well as comparison between radio
occultation technique and GPS ground base. In the first part, We calculated foF2 value from COSMIC Ionphs data in both auxiliary side and occultation side or in latter one only. Both ways show similar results after comparing with Ionosonde. Therefore, the data calculated without Auxiliary side is still credible. In the second part, COSMIC Podtec data, COSMIC Ionprf data and IONEX data in 2008~2010 have been used. The IONEX provides the TEC data between ground station and GPS satellites. The Podtec provides the TEC value between LEO satellites and GPS satellites, we can project the Podtec data onto the direction perpendicular to ground surface at LEO. The TEC data from ground station to LEO can be obtained by substration of these data. The analysis of the results shows high correlation coefficient and obvious relation between slope. During the day time, the correlation coefficient and the average error percentage are better than the in night time; The result shows that the COSMIC Ionprf TEC underestimated the percentage error at about 20% at between ± 30 degrees (low latitude) while it overestimated the percentage error at about 20% in 30~60 degrees(mid-latitudes) during the day time. At night, Ionprf underestimated the percentage error at about 20%.

並列關鍵字

TEC ； IONEX ； PODTEC ； COSMIC

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