机载高分辨CSSAR地面加速运动目标成像方法

Ground accelerating moving target imaging method for airborne high-resolution CSSAR

机载圆轨迹条带合成孔径雷达(circular stripmap synthetic aperture radar,CSSAR)的圆轨迹运动导致目标信号特性复杂、目标距离方程高阶分量显著等问题,给运动目标成像带来很多困难。考虑到高分辨是未来的发展趋势,针对机载高分辨CSSAR,提出一种地面加速运动目标成像方法。首先,针对目标距离方程高阶分量显著的问题,建立了四阶Taylor近似距离模型,以保证成像质量。接着,推导了目标二维频域信号模型,提出通过二维频域相位相乘来高效地实现目标聚焦,并利用差分进化算法高效地实现对距离模型各参数的精确搜索。最后,通过实验验证了所提方法的有效性。

The airborne circular stripmap synthetic aperture radar(CSSAR)has complex target signal characteristics and significant high-order components of the target range equation due to its circular motion,which brings many difficulties to the imaging of moving targets.Considering that high-resolution is the future development trend,a ground accelerated moving target imaging method is proposed for airborne high-resolution CSSAR.Firstly,to address the issue of significant high-order components in the target range equation,a fourth-order Taylor approximate range model is established to ensure the imaging quality.Next,a two-dimensional frequency-domain signal model of the target is derived,and it is proposed to efficiently achieve target focusing through two-dimensional frequency-domain phase multiplication.The differential evolution algorithm is also used to efficiently achieve accurate search of various parameters of the range model.Finally,the experimental results validate the effectiveness of the proposed method.