基于测量数据的机载三维SAR横滚角运动误差补偿

Roll Angle Motion Compensation for Airborne 3D SAR Based on Measurement Data

机载三维SAR通过天线阵列、合成孔径和宽带信号实现三维成像,但平台的平动误差和姿态角误差会影响成像质量。不同阵元间的平动误差一致,可通过单天线SAR运动补偿方法去除,但姿态角误差改变阵元间相对位置关系,影响复杂,其中,横滚角误差影响最大,目前尚没有基于测量数据的补偿方法。本文建立了阵列天线SAR三维成像模型,分析了横滚角误差影响及横滚角误差与跨航向波数之间的关系,提出了波数域子孔径补偿方法,仿真结果证明该方法可有效补偿横滚角运动误差影响。

Array antenna SAR utilizes array antenna, synthetic aperture and wide-band signal to realize three dimensional imaging, which however would be impaired by both translation and rotation error of its platform. Translation error remains same among different antenna units so that it can be eliminated by the motion compensation method for single antenna SAR. Rotation error changes the relative position of antenna units and brings complicated impact in which roll angle motion accounts for the most. Currently there is no effective compensation method based on measurement data. This paper establishes the 3D imaging model of array antenna SAR, analyses the impact of roll angle motion error, then analyses the relationship between roll angle error and cross-track wave-number, proposes a wave-number domain sub-block compensation method. Simulation result shows that the method can effectively compensate the impact of roll angle error.