研究了SAR有源编码辐射定标技术,提出了通过移相器进行方位信号编码,通过混频器进行距离信号调频斜率反向的地物杂波抑制方法;采用RD成像算法获得了分布目标的图像,完成了不同分布和强度的地物杂波与定标参考目标的仿真图像,并采用峰值方法对SAR辐射定标精度进行了定量研究。实验结果证明有源编码辐射定标技术能够有效地抑制地物杂波的影响,提高SAR辐射定标精度。

SAR radiometric calibration accuracy is influenced by background clutter. In order to obtain high radiometric calibration accuracy, certain signal and clutter ratio (SCR) requirement must be satisfied or the SCR should be increased by clutter rejection method. This paper studies Active Coded Radiometric Calibration Technique (ACRCT) of SAR and a clutter rejection method based on azimuth signal phase shifter coding and presents the inversion of rang signal frequency modulation. We adopted Range-Doppler imaging algorithm to simulate reference point target and distributed clutter. We also studied SAR radiometric calibration accuracy by peak value method. Experiment results prove that ACRCT could effectively restrain the influence of background clutter signal and improve the precision of radiometric calibration of SAR.