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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

以自率光束法提升四旋翼UAV航拍影像之定位精度 / Using self-calibration to promote the positioning accuracy of images acquired from a quadrotor UAV

謝幸宜, Hsieh, Hsing Yi Unknown Date (has links)
整合了GPS、INS的無人飛行載具(Unmanned Aerial Vehicles, UAVs),可提供安全、快速的資料蒐集方法,而能執行自動駕駛(automatic pilot)功能的UAV系統,更可提高資料蒐集的自動化程度。資料收集時,UAV系統中的GPS天線、INS系統以及像機的透視中心並不一致,欲以UAV系統執行航測任務時,須先了解UAV的系統幾何與特性,才能從GPS、INS的記錄資料中取得適當的外方位參數參考值。此外,目前的UAV系統多搭載非量測型像機(non-metric camera)獲取影像,但非量測型像機的內方位參數常以近景攝影測量的方式率定而得。然而,能以近景攝影測量方式獲得內方位參數的商業軟體很多,其所使用的函數模式卻未必完全相同,將影響內方位參數的率定成果,若再於空三平差過程中把不同軟體解得的內方位參數視為固定值,將使空三平差的結果產生較大的影像定位誤差。而自率光束法除了可用於近景攝影測量中的像機率定,也能應用於航空攝影測量中,將航測作業中的像坐標系統誤差模式化並加以改正,以提升該次作業的空三平差精度。因此,本研究以較安全的四旋翼UAV系統搭載非量測型像機獲取影像,比較:(1)一般航測方法(即光束法)執行空三平差、(2)使用自率光束法的空三平差、(3)先將所有影像觀測量以熟知的系統誤差模式改正後,再使用自率光束法的空三平差(以下簡稱預改正(pre-corrected)的自率光束法空三平差)所能達到的精度。測試結果顯示:使用預改正的自率光束法空三平差時,使用Brown(1976)與Ebner(1976)兩種附加參數模式,皆可得到最佳的空三平差精度,而使用Brown附加參數模式的自率光束法空三平差精度次之,且均比一般航測方法的空三平差精度佳。但於自率光束法的空三平差過程中使用Ebner的附加參數模式,所得的空三平差精度則最差。 / Unmanned aerial vehicles (UAVs) integrating with GPS and INS provide a safe and fast method for data acquisition. The UAVs which can implement automatic pilot promote the automation of data collection. In UAV systems, the GPS antenna and the INS system are not aligned with the perspective center, so that the GPS and INS records should be revised according to the geometry of UAV systems for exterior orientation references. And the cameras equipped with UAVs are often belonging to the non-metric camera, whose interior orientation parameters can be acquired by close-range photogrammetry softwares. However, there are several different camera models used in the softwares and the interior parameters calibrated by different softwares would not be the same, so that the interior parameters of the non-metric camera should not be regard as constant in aerotriangulation. Self-calibration can not only calibrate the camera in close-range photogrammetry but also model and compensate the departures from collinearity in aerotriangulation to promote the positioning accuracy. This study uses the images acquired from a safe UAV system, a Quadrotor UAV, and compares the results by using different aerotriangulation procedures. In this paper, the optimal accuracy can be obtained by using self-calibration in bundle adjustment with all measurements been pre-corrected for radial and decentering lens distortion. And the suboptumal accuracy can be obtained by using Brown’s (1976) added parameters in bundle adjustment, better than the results of using bundle adjustment. But using Ebner’s (1976) added parameters in bundle adjustment cannot help promoting the positioning accuracy.
2

論美國武裝無人機的國際法問題 / On International law issues concerning U.S. armed UAVs

王正, Wang, Cheng Unknown Date (has links)
無人飛行載具或簡稱無人機是一種不實際搭載乘員的飛行裝置,不論研發的目的為何其核心概念皆是希望以機械來代替人力從事較為辛苦或較為危險的工作;歷史上記載無人機由來已久,但是類議題真正受到國際社會關切乃是2001年9月11日九一一事件後才開始。為了回應九一一事件對美國的威脅,美國除了以行使自衛權為由進攻阿富汗外,更發動了以全球伊斯蘭極端主義份子為對象的「全球反恐戰爭」並且開始大量投入武裝無人機執行定點攻擊行動,狙殺蓋達組織領導人或是與其有關聯的極端主義團體的成員。 隨著反恐戰爭的推進,美國派出的武裝無人機架次也逐年上升,隨之而來的是急遽上升的傷亡人數;驟增的傷亡數,尤其是平民傷亡引起了國際社會關切,其中「美國的武裝無人機攻擊是否違反國際法上關於武力使用的規範」成了急待解決的問題。本論文以當前國際法上關於武力使用的兩大規範:使用武力的合法性(Jus ad bellum)、武力使用的方式(Jus in bello)為途徑,檢視當前美國武裝無人機攻擊是否符合前述兩大規範,進而替美國武裝無人機攻擊衍生的國際法問題提供一個解答。
3

VBS-RTK GPS輔助UAV影像自率光束法空三平差之研究 / VBS-RTK GPS Supported Self-Calibration Bundle Adjustment for Aerial Triangulation of Unmanned Aerial Vehicle Images

李敏瑜, Li, Min Yu Unknown Date (has links)
無人飛行載具(Unmanned Aerial Vehicle, UAV)於要求精度之圖資測製應用時,因飛行高度較低並可在雲下飛行取像,與大型載具相比可更機動性獲取空間解析度較高之影像,雖無法如大型載具酬載大像幅感測器供大區域圖資製作,但於小區域之圖資更新卻相當適合。但一般UAV因酬載重量限制,僅可酬載體積小且重量輕之感測器,如非量測型相機及低精度定位定向系統,即AHRS系統。因此,本研究嘗試在UAV上酬載Trimble BD970 GNSS OEM GPS接收模組,此GPS接收模組體積小且重量輕可安置於UAV上,並透過VBS-RTK GPS定位技術獲取UAV精確飛行軌跡資訊,再經時間內插相機曝光瞬時的GPS資訊供空中控制使用,輔助UAV影像空中三角測量(簡稱空三)平差,以降低地面控制點需求。 但欲引入GPS觀測量供空中控制使用必須考量GPS天線與相機投影中心偏移量之問題,但因UAV所酬載之非量測型相機,將造成此偏移量不易透過地面測量方式測得,於本研究將於空三平差時使用線性漂移參數克服此偏移量無法量測之問題;此外,UAV所酬載之非量測型相機,相機參數乃透過地面近景攝影測量以自率光束法平差方式率定所得,但率定所得相機參數無法完全描述相機在航拍取像時的情況,故本研究於空三平差將採用自率光束法克服相機參數率定不完全之問題。實驗中,首先確定GPS模組BD970在VBS-RTK GPS定位技術下在地面高速移動時可獲得高精度的定位成果;接續驗證線性漂移參數及自率光束法平差於此研究的適用性;最後亦探討不同地面控制點配置及來源對空三平差之精度探討,並提出1/5000基本圖圖資測製精度要求下,VBS-RTK GPS輔助UAV影像自率光束法空三平差的地面控制點最適配置。 / UAV(Unmanned Aerial Vehicle) is currently used in civil purpose such as mapping and disaster monitoring. One of UAV advantages is to collect images with high resolution for mapping demand. However, due to payload limitations of UAV, it is difficult to mount metric aerial camera and precise POS(Positioning and Orientation System) device. Instead, only the non-metric camera and the low accurate AHRS (Attitude and Heading Reference System) can be installed. For mapping demands, Trimble BD970 GNSS OEM board will be carried on the UAV to collect the high accurate flying trajectory as control information for AT (aerial triangulation) by VBS-RTK(Virtual Base Station - Real Time Kinematic) GPS technique. Meanwhile self-calibration bundle adjustment will be employed for AT(Aerial Triangulation) to overcome the imperfect calibration of non-metric camera by the close-range photogrammetric approach. The precise offset between image perspective center and GPS antenna center, called GPS antenna-camera offset, is hard to measure in centimenter level by terrestrial measurement approach. Therefore the drift parameters will be utilized to solve the problem of GPS antenna-camera offset while performing bundle adjustment with self-calibration for AT of UAV images. In the experiments of this study, the height positioning accuracy of BD970 by VBS-RTK GPS approach at high speed movement will be proved firstly. Then the adaptability of drift parameters and self-calibration for GPS supported AT of UAV images will be verified. Finally, the accuracy of AT by using different control information will be analized and appropriate configuration of GCPs(Ground Control Points) for VBS-RTK GPS supported self-calibration bundle adjustment for AT of UAV images will be proposed under the mapping demand with the scale of 1 : 5000.

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