基于波数域子孔径的机载三维SAR偏航角运动误差补偿

机载3维SAR可实现3维成像, 但运动误差会影响成像质量, 其中姿态角误差改变阵元间相对位置, 影响复杂, 目前还没有基于测量数据的补偿方法。该文建立了机载3维SAR成像模型, 分析了姿态角误差对成像的影响, 其中偏航角误差的补偿最为复杂。由回波相位可得航迹向和跨航向波数, 根据这两个波数计算的距离误差与目标位置无关, 消除了误差的空变性。提出在航迹向和跨航向2维波数域分块计算距离误差, 在空域补偿的波数域子孔径补偿方法。仿真结果证明该方法可有效补偿偏航角运动误差的影响。 

Yaw Angle Error Compensation for Airborne 3-D SAR Based on Wavenumber-domain Subblock

Airborne array antenna SAR is used to obtain three-dimensional imaging; however it is impaired by motion errors. In particular, rotation error changes the relative position among the different antenna units and strongly affects the image quality. Unfortunately, the presently available algorithm can not compensate for the rotation error. In this study, an airborne array antenna SAR three-dimensional imaging model is discussed along with the effect of rotation errors, and more specifically, the yaw angle error. The analysis reveals that along- and cross-track wavenumbers can be obtained from the echo phase, and when used to calculate the range error, these wavenumbers lead to a target position irrelevant result that eliminates the error's spatial variance. Therefore, a wavenumber-domain subblock compensation method is proposed by computing the range error in the subblock of the along- and cross-track 2-D wavenumber domain and precisely compensating for the error in the space domain. Simulations show that the algorithm can compensate for the effect of yaw angle error.