臺灣博碩士論文加值系統

本篇論文利用中央大學的雷達站，架設台陽公司的Ka 波段地面天線系統，觀測時間由2003年至2004年系統所接收的資料，針對功率計接收19.5GHz的單頻訊號、大氣自動氣象站所接收的天氣資料進行長期的統計分析，這些天氣資料包含風向、風速、溫度及溼度，目的主要是研究Ka 波段對流層訊號閃爍。而這些統計分析包括利用微分法及移動平均法分別對功率進行計算，功率標準差與風速、溫度、溼度標準差做相關性分析，功率頻譜斜率與風向、風速、溫度及溼度之間的影響，以及探討功率頻譜斜率日變化情形。
由於Ka 波段地面天線系統為短距離的地面傳播，在功率頻譜分析中，實際觀測結果上因大氣折射指數不規則擾動及降雨影響，造成頻譜上只存在電磁波散射特性。
在分析訊號擾動與各大氣參數上的關係發現，功率標準差皆與各大氣參數標準差散佈圖之相關係數成正相關，主因為風速會造成天線基座跟天線盤面共振，而造成大氣折射指數擾動使得訊號擾動因子為溫度與比濕，而比濕擾動使得訊號擾動的貢獻量大於溫度擾動。平均溫度和平均比濕的上升，頻譜斜率會因此會絕對值變大；平均風速在大於4~5(m/s)，斜率平均值絕對值變小。平均溫度之標準差和平均比濕之標準差上升，頻譜斜率會因此會絕對值變大，風速標準差對平均頻譜斜率並無顯注關係。風向與頻譜斜率無關聯，但在春秋季時在風向60度頻譜斜率較其他方向平緩；而經由以上統計分析可建立在短距離地面傳播訊號閃爍特性。

In order to study tropospheric scintillation at 19.5GHz, from 2003 to 2004 year, we setup a Ka-band terrestrial communication system to receive the single strength affected by tropospheric refractivity irregularities. The weather information, such as wind speed, wind direction, temperature, and specific humidity, were also collected simultaneously. The differential and running mean methods were employed to analyze the signals and the correlation between signal strength, wind speed, temperature, and specific humidity were calculated. We also discuss the characteristics of the slope of the power spectrum of the signals to try to realize the relation between the spectral slope and weather parameter.
The results show that positive correlations between signal intensity, wind speed, temperature, and specific humidity, were seen, in which we believe that the wind speed is major factor causing the scintillation of the signals. We also found that when the mean value of temperature and specific humidity were layer, the power spectral slope become steeper. However, where the wind speed is greater than 4m/s, the power spectral slope become gentle, and variance of wind speed seems not to show the correlation with power spectral slope. The diurnal variation of the spectral slope was also presented and discussed in this thesis.

摘要 Ⅰ
目錄 Ⅱ
圖目錄 Ⅳ
第一章前言 1
第二章相關理論基礎 3
2.1 大氣折射率 3
2.2電波閃爍理論 4
第三章實驗儀器說明系統架構 24
3-1自動氣象觀測站 24
3-2 Ka波段雙圓形極化反射面天線系統 24
第四章觀測分析與討論 38
4.1 閃爍資料的定義 38
4.2 資料的取得及處理過程 40
4.3 功率標準差對大氣參數標準差的相關性分析 42
4.4 功率頻譜及其斜率之討論 45
4.5 風向與頻譜斜率之關係 52
4.6 臺灣高雄沿海地區Ka頻段實驗初步結果 53
五.結論與展望 56
5.1結論 56
5.2 未來展望 60
參考文獻 61
附錄 64
圖表 73~104

Ippolito Jr., L.J., “Radiowave Propagation in Satellite Communication＂, Van Nostrand Reinhold Company, New York, 1986 H. Tennekes and J. L. Lumley, “A First Course in Turbulence＂, Cambridge, Massachusetts, and London, England, 1973 p1057~1068, 1984 Michael A. Janssen, “Atmospheric Remote sensing by Microwave Radiometry＂, John Wiley & Sons, Inc., 1993 Ott, R.H., and M.C.Thompson, “Atmospheric Amplitude Spectra in an Absorption Region＂, IEEE Tran. on Ant. And Prop, Vol. AP-26, No.2, March 1978 Glenn Feldhake, “Estimating the Attenuation Due to Combined Atmospheric Effects on Modern Earth-Space Paths＂, PROCEEDINGS OF THE IEEE, VOL. 39, NO. 4, August 1997 Patrizia Basili,Piero Ciotti,Giovanni D＇auria,Paolo Ferrazzoli,and Domenico Solimini, “Case Study of Intense Scintillation Events on the OTS Path＂, Ieee Transactions Antenna & Propagation, Vol.38, No.1, Jan 1990 Vogel, W.J., Measurements of satellite beacon attenuation at 11.7, 19.04, and 28.56 GHz and radiometric site diversity at 18.6 GHz, Radio Science, Vol. 17, No. 6, pages 1511-1520, November-December 1982 Shuen-Peng Shih and Yen-Hsyang Chu, “Studies of 19.5 GHz Sky Radiometric Temperature: Measurements And Applications＂, Radio Science, December 15, 2000 Shih, Shun-Peng, and Yen-Hsyang Chu, Ka Band Propagation Experiments of Experimental Communication Payload (ECP) on ROCSAT-1 – Preliminary Results, Terrestrial, Atmospheric and Oceanic Sciences TAO, Supplementary Issue, 145-164, March 1999 施順鵬，“台灣地區Ka波段大氣傳播通道之研究＂，博士論文，國立中央大學太空科學研究所，2002. 施順鵬, ＂台灣地區人造衛星Ka 波段傳播環境之建立與探討＂, 碩士論文, 國立中央大學, 1996 許舜清, “台灣地區大氣導管現象特性之研究＂, 碩士論文, 國立中央大學, 1995 蔡明嶧, “利用中華衛星一號通訊酬載Ka 波段標識訊號對閃爍效應的研究＂, 碩士論文, 國立中央大學, 2001 蔡佳君，＂低軌道衛星Ka 波段閃爍現象之研究＂ ，碩士論文，國立中央大學太空科學研究所，2003. 曾得浩，“中華衛星一號低軌道衛星 ka 波段雨衰減實驗與模型建立＂，碩士論文，國立中央大學太空科學研究所，2003. 張緒萍，“ka 波段雨衰減之分析與研究＂，碩士論文，國立中央大學太空科學研究所，2004.