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步进频合成孔径雷达(SAR)可以在不要求系统瞬时大带宽的情况下获得距离向高分辨率,在一些领域已得到了成功的应用,但其成像过程中由于雷达与目标之间存在相对运动使得脉冲间对应的瞬时斜距有不可忽略的差值,基于差值导致的距离像偏移、分辨率下降和信噪比损失,提出了在二维频域中补偿的方法。波数域成像算法主要操作是在二维频域,成像精度较高,计算量适中,文中将该算法应用到步进频SAR中,从雷达的几何关系和信号回波模型出发,推导了补偿斜距差的公式,以及实现残余压缩的Stolt插值过程,给出了目标精确聚焦的完整步骤,并分析了Stolt插值频率改变的过程和参数设计的影响,最后对多个点目标进行了成像仿真。
Stepped-frequency synthetic aperture radar (SAR) can obtain the high resolution of range without requiring instantaneous large bandwidth of the system and has been successfully applied in some fields. However, due to the relative relationship between the radar and the target in the imaging process, The motion makes the instantaneous slant distance corresponding to the pulse have a non-negligible difference. Based on the difference of distance image offset, resolution and signal-to-noise ratio loss, a method of compensation in two-dimensional frequency domain is proposed. The main operation of the wavenumber domain imaging algorithm is that in the two-dimensional frequency domain, the imaging accuracy is high and the amount of calculation is moderate. In this paper, the algorithm is applied to the step-frequency SAR. From the geometric relationship of the radar and the signal echo model, The formula of distance difference and the Stolt interpolation process for residual compression are given. The complete steps of target precise focusing are given. The process of changing Stolt interpolation frequency and the influence of parameter design are analyzed. Finally, the imaging simulation of multiple point targets is carried out.