本研究之目的有二，(1)針對中華二號衛星所遙測得到的地表影 像進行模擬，(2)開發幾何處理之模式。由於中華二號衛星尚未升空， 為了建立衛星影像幾何改正模式之測試所需，參考中華二號衛星目前 已公佈之規格，以已經正射、鑲嵌之數位航空影像配合數值地形模型 (DTM)進行中華二號衛星之影像及星曆資料模擬。 為進行中華二號衛星之影像及星曆資料模擬，必須建立一衛星飛 行成像模式。此模式可分為四部份：一為坐標轉換模式，目的在建立 研究所需之坐標系統間彼此轉換關係。二為衛星飛行模式，目的在描 述衛星飛行情形。三為衛星成像模式，目的在進行中華二號衛星影像 及星曆資料模擬。四為星曆資料模式，目的在藉由誤差添加使得模擬 資料更接近真實中華二號衛星飛行情形，而誤差將分系統誤差與隨機 誤差添加在星曆資料中衛星位置與姿態上。 模擬資料產生後，以模擬之資料進行方位求解及定位。在單張影 像部份，以星曆資料建立初始軌道，再在基本影像與模擬之影像上點 選控制點以進行軌道修正後，使用最小二乘過濾模式進行精密軌道修 正，再以檢核點進行定位檢核。在立體對部份，則二張影像在分別經 過軌道修正後，透過前方交會以最小二乘過濾模式進行物空間三維坐 標修正，最後以檢核點進行三位定位檢核。 The objective of this investigation has two folds. One is to simulate ROCSAT-2 images and the other is to develop a applicable model for geometric correction to ROCSAT -2 images. We will use orthorectified aerial image and digital terrain model as referance data to perform imaging simulation. This is due to the unavailability of ROCSAT-2 For ROCSAT-2 image and on-board data simulation, we need to establish a satellite-orbit-model. This model can be divided to four parts. The fisrt one is coordinate-transformation-model which transforms all coordinate systems in this investigation. The second one is satellite-fly-model which describes the satellite orbit. The third one is simulmation-model which simulates ROCSAT-2 image and on-board data. The fourth one is on-board-data-model which simulates on-board data by assuming ROCSAT-2 flying case and adding errors to satellite position and attitude data. The errors include systematic errors and random errors. We compute orientation parameters and position using simulation data. In single image case, we use on-board data to establish initial orbit and correct the orbit with ground control points. Then we use least squares filtering to fine tune the orbit and perform the validation. In stereo images case, we adjust 3-D position in object space by using least squares filtering after correcting orbits of two images. Then the validation
