基于离散FRFT的SAR动目标参数估计方法

Motion Parameter Estimation Method of Ground Moving Targets Based on Discrete Fractional Fourier Transform

为了有效减少SAR系统的数据量和降低脉冲重复频率,提出了一种基于离散分数阶傅里叶变换(FRFT)的动目标参数估计方法。首先对距离向脉冲压缩之后的数据进行DPCA对消处理,其次利用Hough变换估计目标跨航向维的运动参数并校正距离单元走动,然后基于离散的FRFT变换矩阵构造稀疏基矩阵,建立压缩感知重构模型,通过对模型的优化求解获得FRFT的最优阶数,进而估计动目标沿航迹维的速度和位置。最后,仿真实验验证了所提方法能够有效实现低脉冲重复频率条件下的地面运动目标参数估计。

In order to reduce the data amount and pulse repetition frequency of SAR system,a motion parameter estimation method of ground moving targets based on discrete fractional Fourier transform(FRFT)is proposed.Firstly,the DPCA technique is used to cancel the pulse compression echo data in the range direction with dual-channels.Secondly,Hough transform is adopted to estimate the cross-track velocities and range positions of moving targets.And meanwhile,the range cell migration is corrected.Furthermore,the discrete FRFT matrix is adopted as the sparse basis matrix to construct compressed sensing(CS)imaging model.The optimal order is obtained by solving the CS imaging model,with which the along-track velocities and azimuth positions can be calculated.Finally,the simulated results confirm the effectiveness of the method and show that the motion parameters of moving targets can be estimated with low PRF.