Theoretical channels model of synthetic aperture radiometer are presented.Based on this model,how amplitude imbalance,phase imbalance and mutual coupling between the different receiving channels effect brightness temperature retrieving is analyzed.The computer simulation results are also presented,in which the cause of the along-track streaks usually appeared in the retrieved image is identified.In addition,a new system calibration approach is introduced to solve this problem: using digital I-Q vector modulators to simulate the point source in the antenna range,we can get more accurate G Matrix to retrieve the brightness temperature image.This new approach,as compared with the existing calibration methods,is especially suitable for in situ use.
LIU Hao, WU Ji, WU Qiong.
Analysis and Calibration of the Channels Error of Synthetic Aperture Radiometer[J]. Acta Electronica Sinica, 2005, 33(3): 402-406.