全球衛星定位系統(Global Positioning System, GPS) 是一項高精度的定位技術。傳統上使用雙頻觀測以達到高精度定位效果，然而雙頻儀器造價昂貴，因此希望能以單頻觀測的方式達到相同的精度。目前單頻定位誤差最大來源是電離層影響，雖然有IGS提供的全球電離層模型，但不適合表現台灣區域內的變化。本研究利用台灣國土測繪中心提供的本島2006年e-GPS資料，組成零次差的無幾何觀測量，使用球諧函數的概念，估計出適合於台灣的區域性電離層模型，並與IGS電離層模型作比較，以及分析兩者對單頻精密單點定位精度的影響。首先比較台灣上空某一定點(120E,22.5N)之全電子含量差異，發現IGS與台灣區域性電離層模型兩者差值於各時段之RMS值為3~8TECU，且在電離層活躍劇烈時段12:00~18:00差異最大。

進行單頻精密單點定位測試於不同時段時，使用IGS模型可較未使用任何電離層模型提升50%的定位精度；而使用台灣區域性電離層模型時，其定位精度又可較使用IGS模型提升約80~90%，且在電離層活躍時段12:00~18:00提升程度最為明顯。若選用一整天觀測資料進行測試，使用IGS模型時，其定位誤差RMS值為公尺等級，而使用台灣區域性電離層模型時，平面定位誤差約為5cm，高程則約為15cm。因此得知，進行單頻精密單點定位解算時，使用台灣區域性電離層模型可較使用IGS模型能更有效的改善定位誤差，平面定位誤差可達公分等級，高程定位誤差則為公寸等級。

Global Positioning System (GPS) has been known as a high-precision positioning technology. Traditionally, dual frequency equipments provide more accurate positioning; however, they are more expensive than single frequency equipments. Therefore, we hope that positioning accuracy derived from single frequency observations could be the same as dual frequency observations by improving ionospheric correction. The ionospheric delay is currently the primary error of GPS single frequency positioning. Although the Global Ionospheric Model provided by IGS is available for correcting the ionospheric delay, its resolution is too coarse to present the iononspheric activation in Taiwan area. This study focus on the estimation of a Taiwan ionospheric model in terms of spherical harmonic coefficients using the GPS geometry-free observations derived from 2006 e-GPS data provided by National Land Surveying and Mapping Center. A comparison of total electron content difference between the IGS model and the Taiwan local ionospheric model at a specific location (longitude: 120E, Latitude: 22.5N) shows the RMS is 3~8 TECU and the maximum RMS happens at 12:00~18:00 while the ionosphere is extremely active.

Different ionospheric models used for single frequency Precise Point Positioning were tested at different time intervals. Positioning accuracy is improved by 50% using the IGS model compared with no ionospheric model involved. Using the Taiwan ionospheric model can improve the positioning accuracy by 80~90% compared with using the IGS model, and the improvement is significant at 12:00~18:00 time interval. Additionally, if a whole day GPS data are adopted in the test, positioning error is at meter level by applying the IGS model, while positioning error can reach 5 cm in horizontal and 15 cm in vertical after the Taiwan ionospheric model is corrected. In conclusion, the Taiwan ionospheric model used for single frequency Precise Point Positioning has centimeter-level horizontal positioning error and decimeter-level vertical positioning error, which is better than using the IGS model.

摘要 I
Abstract II
致謝 III
目錄 IV
表目錄 V
圖目錄 VI
第一章　緒論 1
§　1-1　前言 1
§　1-2　研究背景與文獻回顧 2
§　1-3　研究動機與目的 3
§　1-4　論文架構 4
第二章　電離層概論與GPS定位原理 6
§　2-1　電離層性質 6
§　2-1-1　電離層結構 6
§　2-1-2　電離層變化特性 7
§　2-2　電離層觀測技術 12
§　2-3　GPS定位原理 13
§　2-3-1　虛擬距離觀測量 13
§　2-3-2　載波相位觀測量 15
§　2-3-3　觀測量誤差來源 17
§　2-4　精密單點定位(PPP)原理 19
第三章　利用GPS觀測量模式化電離層之方法 24
§　3-1　電離層延遲效應與電磁波 24
§　3-2　GPS觀測量與全電子含量關係 30
§　3-3　電離層模式化方法 32
第四章　測試成果與分析 39
§　4-1　研究測試資料 39
§　4-2　研究測試流程 43
§　4-3　台灣區域性電離層模型估計之成果 46
§　4-4　單頻精密單點定位測試 54
第五章 結論與建議 64
參考文獻 66

沈三齊，2005，ITRF2000下台灣追蹤站框架之建立與探討TWVD97坐標系統之變化，國立成功大學測量及空間資訊所碩士論文，台南。
連家慶，2001，中壢動態式電離層控制儀系統控制卡(CRAM Card)重建及測試，國立中央大學太空科學研究所碩士論文，桃園。
陳勇福，2007，利用絕對重力測量與GPS觀測台灣衛星追蹤站高程變化之比較分析，國立成功大學測量及空間資訊學系研究所碩士論文，台南。
楊銘仁，2004，由台灣GPS追蹤站2004年資料建構區域性電離層膜式及其影響定位精度之研究，國立成功大學測量及空間資訊學系研究所碩士論文，台南。
詹紹勳，2007，現代衛星導航，國立成功大學航空太空工程學系課程講義，台南。
蔡和芳，1999，全球定位系統觀測電離層赤道異常之研究，國立中央大學太空科學研究所博士論文，桃園。
Bassiri, S., and Hajj, G. A., 1993, Higher-Order Ionospheric Effects on The Global Positioning System Observables and Means of Modeling Them, Manuscripta Geodaetica, vol. 18, pp. 280-289.
Beutler, G., Bock, H., Dach, R., Fridez, P., Gäde, A., Hugentobler, U., Jäggi, A., Meindl, M., Mervart, L., Prange, L., Schaer, S., Springer, T., Urschl, C., and Walser, P., 2007, Bernese GPS Software Version 5.0, Astronomical Institute, University of Bern, Switzerland.
Bock, O., and Doerflinder, E., 2000, Atmospheric Processing Methods for High Accuracy Positioning with the Global Positioning System, Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy, vol. 26, no. 6-8, pp. 373-383.
Davies, K., 1969, Ionospheric Radio Waves, Blaisdell Publishing Company, Waltham.
Davies, K., 1990, Ionospheric Radio, Peter Peregrinus Ltd, London.
Devore, J. L., 2004, Probability and Statistics for Engineering and Sciences, 6th Edition, Duxbury Publishing Company, Belmont.

Feltens, J., and Schaer, S., 1998, IGS Products for the Ionosphere, Proc. IGS Analysis Center Workshop, Darmstadt, Germany, pp. 225-232.
Gao, Y., and Liu, Z. Z., 2002, Precise Ionosphere Modeling Using Regional GPS Network Data, Journal of Global Positioning Systems, vol. 1, no. 1, pp. 18-24.
Hofmann-Wellenhof, B., Lichtenegger, H., and Collins, J., 2001, Global Positioning System: Theory and Practice, Springer-Verlag, New York.
Hoque, M. M., and Jakowski, N., 2006, Higher Order Ionospheric Effects in Precise GNSS Positioning, Journal of Geodesy, vol. 81, no. 4, pp. 259-268.
International GNSS Service, IGS. http://igscb.jpl.nasa.gov/components/prods.html
International Service of Geomagnetic Indices, ISGI. http://www.cept.ipsl.fr
Klobuchar, J. A., 1987, Ionospheric Time-Delay Algorithm for Single Frequency GPS Users, IEEE Transactions on Aerospace And Electronic Systems, vol. AES-23, no. 3, pp. 325-331.
Klobuchar, J. A., 1991, Ionospheric effect on GPS, GPS world, vol. 2, no. 4, pp. 48-51.
Komjathy, A., 1997, Global Ionospheric Total Electron Content Mapping Using the Global Positioning System, Ph.D dissertation, Department of Geodesy and Geomatics Engineering Technical Report No. 188, University of New Brunswick, Canada.
Liu, Z., Skone, S., Gao, Y., and Komjathy, A., 2005, Ionospheric Modeling using GPS data, GPS Solutions, vol. 9, no. 1, pp. 63-66.
Mannucci, A. J., Wilson, B. D., Yuan, D. N., Ho, C. H., Lindqwister, U. J., and Runge, T. F., 1998, A Global Mapping Technique for GPS-derived Ionospheric Total Electron Content Measurements, Radio Science, vol. 33, no. 3, pp. 565-582.
McCarthy, D. D., 1996, IERS Conventions, Technical Note No. 21, Observatory of Paris, Paris.
McNamara, L. F., 1991, The Ionosphere: Communications, Surveillance, and Direction Finding, Krieger Publishing Company, Florida.
National Aeronautics and Space Administration, NASA. http://solarscience.msfc.nasa.gov/
National Weather Service Space Weather Prediction Center, NOAA. http://www.swpc.noaa.gov/

Ping, J., Kono, Y., Matsumoto, K., Otsuka, Y., Saito, A., Shum, C., Heki, K., and Kawano, N., 2002, Regional Ionosphere map over Japanese Islands, Earth Planets Space, vol. 54, no. 12, pp. 13-16.
Schaer, S., 1999, Mapping and Predicting the Earth's Ionosphere Using the Global Positioning System, Ph.D dissertation, Astronomical Institute, University of Bern, Switzerland.
Schaer, S., Beutler, G., Rothacher, M., and Springer, T. A., 1996, Daily Global Ionosphere Maps Based on GPS Carrier Phase Data Routinely Produced by the CODE Analysis Center, Proc. IGS Analysis Center Workgroup, Maryland, USA, pp. 181-192.
Schaer, S., Gurtner, W., and Feltens, J., 1998, IONEX: The IONosphere Map EXchange Format Version 1, Proc. IGS Analysis Center Workshop, Darmstadt, Germany, pp. 233-247.
Seeber, G., 2003, Satellite Geodesy 2nd Edition, Walter de Gruyter, New York.
Tascione, T. F., 1988, Introduction to Space Environment, Florida, Orbit Book Company.
Teunissen, P. J. G., 1995, The Least-square Ambiguity Decorrelation Adjustment : A Method for Fast GPS Integer Ambiguity Estimation, Journal of Geodesy, vol. 70, no. 1-2, pp. 65-82.
Wild, U., 1994, Ionosphere and Geodetic Satellite Systems: Permanent GPS Tracking Data for Modeling and Monitoring, Ph.D dissertation, Vol. 48 of Geodätistiche-geophysikalische Arbeiten in der Schweiz, Schweizerische Geodätistiche Kommission, University of Bern, Switzerland.
Xu, G., 2003, GPS Theory, Algorithms and Application, Springer-Verlag, New York.
Yeh, K. C., and Liu, C. H., 1972, Theory of Ionospheric Waves, Academic Press, New York.
Zumberge, J. F., Heflin, M. B., Jefferson, D. C., Watkins, M. M., and Webb, F. H., 1997, Precise Point Positioning for the efficient and robust analysis of GPS data from large network, Journal of Geophysical Research, vol. 102, no. 3, pp. 5005-5017.