相位中心偏差对机载阵列天线下视3D-SAR成像影响分析

摘要

阵列下视3D-SAR采用阵列天线实现3维分辨成像,阵列天线包含的大量阵元天线不可避免地会存在相位中心偏差,这会在回波信号中引入相位误差,影响阵列下视3D-SAR 3维成像.该文首先建立了相位中心偏差分析模型,然后在此基础上采用随机过程正交展开法,基于标准勒让德正交基将相位中心偏差带来的回波相位误差展开为正交多项式,分析了其对图像主副瓣性能及对比度的影响,并给出了统计规律上的积分旁瓣比与相位中心偏差方差的关系.最后通过仿真结果验证了理论分析的有效性.%The Linear Array Downward-Looking 3D-SAR (LADL 3D-SAR) achieves the ablity of resolving imaging in three dimensions using linear array antennas. The phase center variations of linear array antennas, which is unavoidable under real condition, will lead to echo phase errors that impact the imaging of 3D-SAR. In this paper, the analyzing model of the phase center variation is firstly established, then the impact of phase errors caused by phase center variations in LADL 3D-SAR is discussed based on stochastic process orthogonal expansion.The impact on sidlobe and the statistical relationship between ISLR and the deviation of phase center variations is derived analytically. Finally, the simulation results demonstrate the effectiveness of the theoretical analysis.