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    題名: 低成本微衛星之氣象觀測任務與星系設計;The Weather Observation Mission and Constellation Desigh for Low-Cost Micro-satellites
    作者: 林宗憲;Chung-Hsien Lin
    貢獻者: 機械工程研究所
    關鍵詞: 星系設計;微衛星;氣象觀測;weather observation;microsaotllite;constellation design
    日期: 2004-01-30
    上傳時間: 2009-09-21 11:37:54 (UTC+8)
    出版者: 國立中央大學圖書館
    摘要: 本文主要目的為設計一個低成本的衛星任務及星系,能提供涵蓋台灣的氣象雲圖。基於低成本的考量,本文參考一般業餘衛星的發展經驗,採用被動式磁力姿態控制系統,並盡量使用可接受的非太空規格商業產品,主要的酬載為具有廣角鏡頭的CCD拍照系統。 本文主要分為拍照系統設計及衛星星系設計兩個部份,在第二章我們先定義衛星的任務目標及需求,並加以分析討論及定義衛星的拍照需求、指向需求及衛星星系的覆蓋需求。而第三章針對前面所定義的任務需求設計衛星的拍照系統,我們利用衛星的軌道及姿態變化的特性,設計了衛星的拍照區域及拍照邏輯,可以保證每天獲得一張涵蓋台灣的氣象雲圖。另外,我們定義了兩個指向誤差參數:最大參考指向誤差及平均參考指向誤差,用以分析拍照系統的指向誤差是否符合拍照系統的指向需求,結果發現可以利用CCD的安裝角度來獲得最小的指向誤差。更進一的分析發現,同樣的安裝角度可以適用於與台灣相同地磁緯度的目標。我們接著利用安裝多組不同安裝角度的CCD相機,可以針對位於某一地磁緯度頻帶的目標拍照。 在第四章我們利用前面所設計的拍照系統和衛星搭載系統,針對衛星星系的覆蓋需求,設計一個可以每小時獲取一張氣象雲圖的衛星星系。我們採用Walker星系的設計方法,發現由14個相同衛星所組成的14/14/0星系,可以滿足最大覆蓋間隙小於一小時的任務需求。分析的結果發現,14/14/0的Walker星系具有可以提供位於緯度頻帶±33度內的任何目標,最大覆蓋間隙小於一小時的特性。我們將這個結果與第三章中利用多組CCD相機的設計結合,提供位於某特定緯度的區域目標每小時一張氣象雲圖的功能。我們將這個結果應用到觀測移動中的目標(如颱風)的用途上,模擬觀測桃芝颱風的結果發現,在102小時內我們可以獲得127張氣象雲圖。 最後在第五章我們對本文做了一些結論,並提出研究成果的應用,以及其未來發展的方向。 The main goal of this dissertation focuses on the low-cost space mission and constellation design for acquiring weather images of Taiwan. Due to the low-cost requirement, the passive magnetic attitude control system is employed. The components of bus-system also use as many of off-the-self parts as possible. The primary payload of spacecraft is the imagery system possessed the CCD camera with wide angle of field of view. This dissertation contains two main subjects: the imagery system design and the constellation design. In Chapter 2, the mission requirements, imaging requirements, pointing requirements and coverage requirements are defined and analyzed according to the mission objectives. In Chapter 3, the imagery system is designed according to the mission requirements defined in Chapter 2. According to the characteristics of attitudinal and orbital motion of spacecraft, the shooting zone and imaging logic are designed for acquiring weather images of Taiwan per day. The maximal and mean reference pointing errors are defined to analyze the pointing error of imagery system. The calculation result shows that the minimum pointing error can be obtained by means of employing an optimal setup angle of CCD cameras. It is found that the imagery system design for Taiwan can be applied to the other targets located at the same geomagnetic latitude as that of Taiwan. Furthermore, the imagery system with multi-cameras is extended to observe an area target at a specified geomagnetic latitude band. In Chapter 4, a constellation for acquiring the weather images of Taiwan hourly is designed according to the coverage requirements defined in Chapter 2. The bus-system and imagery system designed in Chapter 3 are also employed in the satellites of constellation. The calculation result shows that the 14/14/0 Walker constellation can satisfactory meet the mission requirement of taking pictures hourly. The analysis of present constellation design also shows that the maximal coverage gap of 14/14/0 constellation is less than one hour at the latitude band of ± 33 deg N. The combination of 14/14/0 constellation and the imagery system of multi-cameras in Chapter 3 can provide the weather images of an area target, which is located at a specified geomagnetic band. This result is also applied to observe a moving target, such a typhoon, within a warning area including Taiwan. The simulation of observing typhoon Taraji shows that 127 images can be acquired during 102 hours. In Chapter 5, the conclusions of this dissertation are given and the suggestions of the future applications of present study are also proposed.
    顯示於類別:[機械工程研究所] 博碩士論文

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