低频UWB SAR图像的辐射校准

Radiometric calibration for low frequency UWB SAR images

常规SAR辐射校准技术不能适用于低频超宽带合成孔径雷达(ultrawidebandsyntheticapertureradar,UWBSAR)系统。提出低频UWBSAR的辐射校准必须考虑定标体的低频散射特性,并建立基于ω-κ成像算法的理想点目标回波模型。利用矩量法(methodofmoment,MoM)和渐近波形估计(asymptoticwaveformevaluation,AWE)方法获得定标体散射特性后,对目标回波模型进行修正使之能够正确反映目标的散射特性。最后给出辐射校准的方法,并通过计算机仿真验证了该方法的有效性。

The calibration techniques developed for the regular SAR system can not be used for low frequency ultra wide band synthetic aperture radar (UWB SAR) system. It is proposed that the low frequency scattering characteristics of the calibrators should be considered during the calibration of the system. Based on w-k imaging algorithms, the model of echo from an ideal point target is given and corrected using the scattering characteristics of calibrator calculated using method of moment (MoM) and asymptotic waveform evaluation (AWE). In the end, the calibration method is proposed and computer simulation is used to verify this method.