线性调频步进信号雷达目标运动参数估计方法

针对目标运动对线性调频步进信号雷达成像的影响,提出一种基于时频分析的目标运动参数估计方法。对差频处理后的各簇回波信号进行快速傅里叶变换,利用变换后信号与子脉冲序列的线性调频关系,通过维格纳分布和Radon变换对目标不同时刻运动参数进行估计。结合二值数学形态学与图像边缘检测方法提高对多散射点目标运动参数估计的精度。在此基础上,针对目标可能出现的变速运动情况,利用最小二乘算法拟合整个成像时间内目标运动速度的变化,较好地实现对机动目标的运动参数估计。仿真实验验证了本文方法的有效性。

Motion parameter estimation for frequency-stepped chirp signal ISAR target

Motion parameter estimation method based on time-frequency analysis is proposed to overcome the influence of the target movement on its image in frequency-stepped chirp signal radar system.By taking the Fourier transform for the echo after dechirp firstly,based on the linear frequency modulation of the subpulses sequence,the motion parameter at every time can be estimated by the method which is combined by Wigner-Ville distribution(WVD) and Radon transform.Then,the binary mathematical morphology and edge detection method is used to improve the accuracy of the velocity estimation of the target which contains many scatterers.Finally,the least-square algorithm is used to obtain the motion parameters with better accuracy when the maneuvering target velocity varied within the imaging time.Simulation verifies the validity of motion parameter estimation method proposed in this paper.