本文發展主動式雷達校正器校正C-Band合成孔徑影像雷達系統，利用它對於兩顆C-Band的ERS-2與ENVISAT合成孔徑雷達衛星進行校正實驗[1]。2002年3月1日，歐洲太空總署發射了另一顆極軌道地球觀測衛星ENVISAT，它提供對於大氣、海洋、陸地、冰河的測量超過五年以上的觀測週期，ENVISAT上面搭載著新穎的籌載合成孔徑雷達系統，以確保對於即將完成任務的ERS-2能夠繼續延續觀測。主動雷達校正器的設計為利用兩支傳送天線同時產生垂直與水平極化的回波，為了進行輻射校正，對於主動式雷達校正器系統4 s的延遲時間、系統的增益(RCS=75.97dBm2)都經過精確的驗證。為了進行C-Band合成孔徑雷達校正實驗，本篇論文把主動雷達校正器佈置後從雷達影像上得到輻射校正係數(K)值，估算出精準的方位角與仰角，並從影像上檢查回波大小以及主動式雷達校正器佈置的位置，在影像上，預期延遲的點會依據主動式雷達校正器系統延遲的時間。所以此篇論文敘述有(1)主動式雷達校正器元件與延遲時間的一些系統特性測量。(2)經由處理完成影像上對於絕對校正參數(K)值的計算方法與結果。 This paper developed an Active Radar Calibrator to calibrate the C-band SAR imaging radar system, we carried out the design process of the Active Radar Calibrator (ARC) and calibration experiment of the C-band synthetic aperature radar (SAR) of both ERS-2 and ENVISAT. On I March 2002, the European Space Agency launched ENVISAT, an advanced polar-orbiting Earth observation satellite which will provide measurements of the atmosphere, ocean, land, and ice over a five year period. The ENVISAT satellite has an ambitious and innovative payload that will ensure the continuity of the data measurements of the ESA ERS satellite. The ARC is designed return both V and H radar signals with two transmission antennas and it was identified clearly including a 4 s delay and system gain(RCS=75.97dBm2) for radiometric calibration. For calibration of the C-band SAR, we have employed an ARC located in grassland near the Jhong-Ping elementary school in Chung-Li, Taiwan. We estimate the accurate azimuth and elevation angles in order to acquire the calibration constant (K) from the image data, we have examined image amplitude (date numbers) and locations of the ARC. It is seen in the SAR image, as expected, that the positions of the ARC delay points are shifted depending on the delay time.This paper describes (1) The ARC design process and laboratory measurement performed to characterize the hardware performance, with measurement of component and propagation delay. (2) the method and preliminary results of the calibration constant (K) from the image date.
