雷達影像可以全天候的觀測地球環境變化，因此使用合成孔徑雷達影像做資料的分析與蒐集(例如:地物分類，國土監測，地形變遷，海洋污染…等)，有無法取代的優勢。 要分析合成孔徑雷達影像資料，影像的輻射校正與幾何校正是非常重要的步驟。本實驗室目前已分別發展出利用延遲器產生斜距方向移動點，或使用頻移器產生方位方向移動點，來做為影像的幾何校正控制點與輻射校正參考點。 本研究將改良僅能產生上下兩對稱移動點且能量較弱的舊式頻移器，利用耦合效應，改良後的校正器可以得到數十個可靠的方位方向移動點，提供方位方向的幾何校正參考點。獲得到的校正係數K值，可作為精密輻射校正之用。 Synthetic aperture radar(SAR) is capable of observing the changes of Earth surface in all weather. Furthermore, It has a deal of the advantages to analyze and to collect the information about the earth’s environment , such as the geological classification, the territorial defense , the movement of the Earth’s surface , and the ocean polluted extent, to name a few. However, precise geometric and radiometric calibrations will be the vital process. Our team has developed the delay line and the multiplier to introduce shift points at range direction and azimuth directions respectively. This study devotes to improving old calibrator that produces only two symmetric shift points with weak power returns. Experiments show that the new calibrator can provide many more shift points along the azimuth direction. It demonstrating that if is useful for precise geometric and radiometric calibrations for satellite SAR.
