臺灣博碩士論文加值系統

電離層斷層掃描網是一個非常適合用來作為研究大尺度大範圍的系統 ， 特別是台灣地區正恰好可觀察到赤道異常區的大尺度電子濃度的變化。
過去於西元1992春季，中央央大學成立低緯度電離層掃描網 (, Low Latitude Ionospheric Tomographic Network , LITN) 此掃描網由北向南共有六個觀測站中國大陸的上海、溫州、臺灣的中壢、高雄、菲律賓的碧瑤和馬尼拉是利用美國海軍導航衛系統 (, Naval Navigation Satellite System , NNSS) 和接收機JMR –1 藉由斷層掃描技術來做為電離層的電子濃度二維的分布圖(Tsai et al . , 2000 ; Huang et al . , 1997 ; 黃啟瑞 , 1997 ) ，但現今NNSS衛星系統中有些衛星已經失效為了能繼續能研究臺灣區上空附近的電離層所以必須重建電離層斷層掃描網。現在於2003年7月中央大學開始向美國NWRA(NorthWest Research Associates , Inc . ) 購置ITS 接收機預計先後在台灣中壢中央大學 、 草屯南開技術學院和屏東海生館成立接收站， 成立低緯度電離層觀測掃描網( LITN )而後希望推展至國外其它地方如菲律賓和印尼等使觀測範更加廣大。
而本文中會使用STK衛星軌道模擬軟體與IRI-model來找出衛星的軌道位置與初始值，去找出GPS/MET與真實LITN之電子濃度分佈。結果將與動態電離層觀測儀做比較。
福爾摩沙衛星三號升空待其飛到各自的軌道上 ，將可收集到到更多的資料 (六顆低軌道衛星 和多一個頻率1066.66MHZ)，來作為電離層觀測掃描的反演。

The Low Latitude Ionospheric Tomographic Network (LITN) suitable for the study of lare scale ionosphere structure , especially in the Taiwan area , we can study the large scale electron density variation in the equatorial anomaly region .
In the past, NCU had begun to set up LITN . It consisted of six ground-based receivers spanning 20∘along Taiwan meridian (121∘E) to receiver beacon signals from the US Naval Navigation Satellite System (NNSS) with receiver JMR-1 in order to carry out the large scale experiments on two-dimensional ionospheric imaging by computerized tomography until the decommission of NNSS satellites in late 1997.Since July 2003, NCU has purchased 4 ITS30 receivers from North West Research Associates, Inc. (NWRA) and set them in Pingtung , Nantou and Taoyuan in Taiwan for the reestablishment of the NEW LITN with the hope to promote the receiving stations to other countries such as Philippines , Indonesia and so on in the near future .
In this thesis, We have applied STK ,IRI-model to determine the location of LEO satellite and initial electron number density . In addition, the simulation study of GPS/MET and real data inversion with the ITS receiver were accomplished. A comparison is made between our results and dynasonde data, some possible explanation were discussed.
After Formosat-3, which consist of six LEO satellites and one more frequency band (1066.67MHz), entered into their orbits, we can get more data for the inversion of CIT study.

中文摘要………………………………………………..…………..Ⅰ
英文摘要…………………………………………………...………Ⅲ
目錄...................................................................................................Ⅳ
圖目錄……………………………………………...………………Ⅶ

表目錄……………………………………………………...…….... Ⅸ


第一章 緒論…………………………………………….…….……1
1-1 斷層掃描(Tomography)…………………………………..……..1
1-2 電離層斷層掃瞄簡介……………………………….……….….1
1-3 電離層與赤道異常現象……………………………….…….….2
1-3-1電離層.......................................................................................2
1-3-2赤道異常現象..............................................................................3

第二章 衛星軌道的模擬與ITS系統……………………….…..…5
2-1 STK ( Satellite Tool Kit ) 衛星軌道模擬軟體…………..….…5
2-1-1 LEO衛星軌道的模擬..............................................................6
2-2 ITS 衛星接收系統…………………………………….…….…7
2-2-1接收衛星....................................................................................7
2-3 福爾摩沙衛星三號(中華衛星三號)………...........….………..11
2-4 硬體與設備(操作手冊):ITS 30……………………….……….14
2-4-1控制軟體軟體介紹..................................................................15
2-4-2 Its-30 接收機訊號流程簡圖..............................................18
2-4-3 norad.dat 衛星的軌道參數................................................20

第三章 斷層掃描的模擬研究與 IRI model 簡介………............22
3-1 IRI model 簡介……………………….…………………...…..22
3-2 IRI模式操作之簡介…………………….……………………....26

第四章 斷層掃描重建理論………………….………………….…..29
4-1 簡介………………………………………………………………29
4-2 迭代演算法………………………………………………………29
4-2-1代數重建法( Algebraic Reconstruction techniques, ART ) 31
4-2-2倍數代數重建法( Multiplicative Algebraic Reconstruction techniques, MART ) ..........................................................................32
4-2-3同步重建法 ( Simultaneous Iterations Reconstruction Technique SIRT,)..............................................................................33


第五章 資料分析與結果…………………………………..………..34
5-1STK所模擬的NNSS系列衛星的位置…………………….…….35
5-2運用STK與IRI-model來做的GPS-MET遮蔽觀測的模擬資料............................................................................................................36
5-2-1 資料流程................................................................................ 36
5-2-2斷層掃描的最後結果..............................................................37
(1)利用STK所模擬出的2004 3月18日福衛三號(LEO)與GPS衛星軌道的軌跡.......................................................................37
(2) GPS與LEO交錯點(log)............................................43
(3)2004年3月18日前兩小時的全球電子濃度25km-825km之tomography的切片.................................................................44
5-3 運用ITS系統與IRI_model 在臺灣地區上空的tomography…..49
5-3-1五月一日pm12:10的結果....................................................49
5-3-2 南北向10S-50N 東西向由100∘E到135∘E連續的電子濃度圖..................................................................................53

第六章 未來展望與結論……………………………………………57
未來展望................................................................................................57
結論........................................................................................................58
參考文獻………………………………………………………………59

參考文獻
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Austen, J. R., S. J. Franke, and C. H. Liu, 1988: Ionospheric imaging using computerized tomography. Radio Sci., 23, 299-307.
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周展毅, GPS信號遮蔽觀測於電離層斷層掃描之模擬研究 2004
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