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Title: | 應用長期連續GPS觀測資料於坐標參考框架變異之研究 A Study on Reference Frame Variations Based on Long-term GPS Measurements |
Authors: | Syu-Wei Yu 余徐維 |
Advisor: | 韓仁毓(Jen-Yu Han) |
Keyword: | 全球定位系統,坐標參考框架,變形分析,動態坐標框架轉換, Global positioning system.,Reference Frame,Deformation Analysis,Time-variant Transformation, |
Publication Year : | 2009 |
Degree: | 碩士 |
Abstract: | 根據板塊運動理論,地球表面可分為數個剛體板塊,板塊之間每年以數公厘至數公分不等之速率相互移動,因此由地表控制點位所定義之坐標參考框架也會隨時間而變動。以往透過傳統測量方式並無法得到地表點位之連續細微變化,但隨著現代科技的發展與衛星大地測量技術的進步,加上全球定位系統( Global Positioning System, GPS )的問世,可對地表點位進行長期連續的觀測,有效偵測地表動態行為,進而解算出點位空間資訊。而在不同時期或使用不同測量技術經觀測解算得到之坐標與速度場,其所依據之參考框架定義亦不盡相同,一般可透過以相似轉換為基礎之動態框架轉換模型,對不同坐標參考框架進行轉換,使其具有共同基準,以利後續應用。
本研究主要目的為建立一套完整的動態框架轉換模型參數估計程序,包含從GPS原始觀測資料的處理開始,透過完整的GPS定位解算以及序列資料處理流程,以獲得高品質的地表動態資料,作為後續應用之可靠依據;並採用嚴謹的參數估計平差模型(包含廣義平差模型與虛擬觀測平差模型),選擇合適之動態框架轉換模型進行轉換參數估計,評估參數顯著性,在不設限參考框架變異行為的情況下,期望能夠透過這套流程有效建立變形框架間之動態轉換關係。 根據數值成果顯示,在以台灣GPS衛星追蹤站2001年至2007年RINEX資料作為分析基礎下,本研究所建立的序列資料處理流程能夠顯著地提升所獲得的地表動態行為估計品質,此外由於台灣地區地表點位存在不均勻的變形行為,若以現有動態相似轉換模型加以模式,將會降低坐標及速度場轉換品質,而動態仿射轉換模型則因為其可以有效處理非均勻變形場,對於台灣地區動態框架轉換參數之顯著性以及坐標、速度場之轉換品質均將有明顯助益,可做為未來在變形區域建立動態坐標系統時之主要參考模型。 According to the tectonic theory, the Earth’s surface can be divided into several rigid plates which move with respect to each other with velocities from millimeters to centimeters per year. Consequently, the coordinates of ground control points defining a terrestrial reference frame will also vary with time. In the past, detecting the tiny surface movements using traditional surveying technique is not an easy task. In recent years, with the advance of space geodesy techniques and the application of the Global Positioning System ( GPS ), the dynamical behavior of the Earth’s surface can be continuously observed and precisely determined. As soon as the time-variant coordinates and velocities of ground control points can be estimated, the geometric relations between terrestrial reference frames at different epochs can be established using a time-variant reference frame transformation model. The purpose of this study is to develop a complete procedure for establishing a time-variant reference frame transformation model. First, the high quality information for the coordinates and velocities of ground control stations are obtained by an integrated GPS data processing and time-series improvement procedure. Then a rigorous parameter estimation approach ( including a general and a unified least-squares techniques ) is proposed for estimating the parameters of different time-variant transformation models. The estimated parameters are tested for their statistical significance and the actual geometric relations between time-variant reference frames can thus be identified. In the numerical analysis, the RINEX data from 2001 to 2007 of seven GPS tracking stations in Taiwan area has been processed and analyzed. The results show that the quality of the velocity estimations can be significantly improved by applying the proposed time-series improvement approach. Furthermore, due to the non-uniform deformations in this area, a time-variant similarity transformation model does not provide an acceptable result. On the other hand, a time-variant affine transformation model can produce a coordinate and velocity transformation of a higher quality due to its capability on modeling non-uniform deformations. Consequently, a time-variant affine transformation model can serve as an eligible candidate model especially in establishing a time-variant reference system in a deforming area. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/9472 |
Fulltext Rights: | 同意授權(全球公開) |
Appears in Collections: | 土木工程學系 |
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ntu-98-1.pdf | 2.44 MB | Adobe PDF | View/Open |
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