基于相位追踪的SAR运动目标高阶距离徙动校正方法

A New Approach to High-order Range Cell Migration Correction for SAR Ground Moving Targets Based on Phase Tracking

距离徙动校正(RCMC)是合成孔径雷达(SAR)实现运动目标参数估计和聚焦成像的关键环节。当目标或平台运动复杂时,传统低阶RCMC方法将不再适用,而现有基于参数化的高阶RCMC方法易存在模型失配和计算复杂度高的问题、现有非参数化方法在低信噪比下性能也将大幅下降。对此,该文借助扩展卡尔曼滤波(EKF)对造成RCM的相位进行追踪,进而构建RCM补偿函数实现RCMC。所提方法不依赖于RCM的具体模型,追踪得到的相位包含高阶分量,因此可以实现SAR运动目标的高阶RCMC。此外,EKF在进行相位追踪的同时能对信号进行滤波处理,可有效降低所提方法的信噪比(SNR)门限。与传统方法相比,该方法适用性广,计算量适中,且能校正不可忽略的高阶残余距离徙动。该文详细阐释了所提方法的原理及数学模型,并通过多组仿真和实测数据处理验证了所提方法的有效性和优越性。

Range Cell Migration Correction(RCMC)represents an important advancement in the estimation of moving target parameters and imaging of targets in high-resolution Synthetic Aperture Radar(SAR)systems.When the motion of a target or platform becomes complex,the traditional low-order RCMC method may no longer be suitable.Meanwhile,the existing high-order RCMC method based on parameterization is susceptible to issues such as model mismatch and high computational complexity.Additionally,its performance may decrease significantly under a low Signal-to-Noise Ratio(SNR).This research utilizes Extended Kalman Filter©The Author(s)2024.This is an open access article under the CC-BY 4.0 License(https://creativecommons.org/licenses/by/4.0/)(EKF)to track the phase responsible for RCM and develop a phase compensation function to achieve RCMC.The proposed approach is model-independent and can track high-order components in the phase,thereby enabling high-order RCMC of moving targets in SAR.In addition,EKF can filter signals during phase tracking to effectively lower the SNR threshold of the proposed method.Thus,this method offers broad applicability,moderate computational complexity,and the ability to correct non-negligible high-order residual range cell migrations,thereby distinguishing it from traditional methods.This study thoroughly explains the principles and mathematical model behind the proposed method,demonstrating its effectiveness and superiority through multiple sets of simulations and measured data processing.