In multi-channel synthetic aperture radar-ground moving target indication (SAR-GMTI), most radial velocity estimation methods are based on the phase difference between channels. However, the image coregistration and channel phase errors will have a severe impact on the phase difference between channels. Moreover, it deteriorates the performance of the moving target radial velocity estimation. To solve this problem, a robust radial velocity estimation method is proposed using a frequency diverse array-SAR (FDA-SAR) in this letter. By introducing the step frequency, the interferometric phase among channels is a linear function of the Doppler frequency. The radial velocity of moving targets is embedded in the first-order term of the linear function. Meanwhile, the first-order term does not include channel phase error terms. Therefore, the accurate velocity of moving targets is estimated by the first-order coefficient which is solved by the least-squares fitting method. Afterward, according to the analysis and derivation, the proposed method is robust on the condition of image coregistration error. At last, simulations and data analysis illustrate the effectiveness of the proposed method.

中文翻译：

---

一种用于 FDA-SAR 的稳健径向速度估计方法

在多通道合成孔径雷达-地面动目标指示（SAR-GMTI）中，大多数径向速度估计方法是基于通道之间的相位差。然而，图像配准和通道相位误差会对通道之间的相位差产生严重影响。此外，它恶化了运动目标径向速度估计的性能。为了解决这个问题，本文提出了一种使用频分阵列SAR（FDA-SAR）的鲁棒径向速度估计方法。通过引入阶跃频率，信道间的干涉相位是多普勒频率的线性函数。运动目标的径向速度嵌入到线性函数的一阶项中。同时，一阶项不包括信道相位误差项。所以，运动目标的准确速度是通过最小二乘拟合法求解的一阶系数估计的。之后，根据分析和推导，该方法在图像配准误差条件下具有鲁棒性。最后，仿真和数据分析证明了所提出方法的有效性。