基于修正电磁散射系数的距离频域脉冲相干法SAR回波仿真

SAR Echo Simulation of Range Frequency Domain Pulse Coherence Method Based on Electromagnetic Scattering Coefficient Correction

针对传统合成孔径雷达(Synthetic Aperture Radar,SAR)回波仿真方法无法同时满足仿真精度高、速度快的缺点,设计了一种利用距离历程修正电磁散射系数的距离频域脉冲相干法(Range Frequency Domain Pulse Coherence,RFPC)目标回波仿真方案。该方案在离散方位采样点处采用物理光学法计算关于目标电磁散射特性的二维电磁散射系数,利用天线相位中心与目标间的距离历程修正电磁散射系数的相位,根据脉冲信号3 dB波束宽度修正电磁散射系数的幅度,利用RFPC在距离频域进行目标电磁散射系数与SAR发射信号的乘积处理,获取目标的二维回波信号,采用RD成像算法进行成像处理得到目标的SAR仿真图像。利用该方案分别对金属球和舰船模型进行了回波仿真试验,并与RaySAR的仿真结果进行对比,验证了该方案的精确性与高效性。

As traditional Synthetic Aperture Radar(SAR)echo simulation method cannot meet the need of high simulation accuracy and high speed at the same time,a Range Frequency Domain Pulse Coherence(RFPC)method for target echo simulation scheme that uses range history to correct electromagnetic scattering coefficients is proposed.This scheme calculates two-dimensional electromagnetic scattering coefficients about target electromagnetic scattering characteristics at the discrete orientation sampling points using the physical optics method.The phase of the electromagnetic scattering coefficient is corrected by the range history between the antenna phase center and the target.The amplitude of the electromagnetic scattering coefficient is corrected according to the 3 dB beamwidth of the pulse signal.Using the range frequency domain pulse coherence method,the product of the target electromagnetic scattering coefficient and SAR emission signal is processed in the range frequency domain to obtain the two-dimensional echo signal of the target.The RD imaging algorithm is used for imaging to obtain the SAR simulation image of the target.Using this scheme,the echo simulation experiments of metal sphere and ship model are carried out,and the accuracy and efficiency of this scheme are verified by comparing with the results of RaySAR simulation methods.