基于迭代运动补偿的船载HFSWR展宽弱目标DOA估计

Estimation of the DOA for Weak Targets in Shipboard HFSWR Based on Iterative Motion Compensation Technique

  • 摘要: 船载高频地波雷达(High Frequence Surface Wave Radar, HFSWR)的平台机动运动会使目标回波信号展宽,导致其信噪比降低并产生弱目标,进而影响目标检测和测向精度。针对船载平台机动运动引起的展宽弱目标测向问题,本文提出一种基于迭代运动补偿的船载地波雷达展宽弱目标测向方法。该方法通过迭代逼近策略,实现了对目标回波信号的补偿与测向一体化处理,克服了传统补偿方法需已知目标方位角才能达到最佳补偿效果的问题;同时引入了四阶累积量重构阵列导向矢量,并结合确定性最大似然测向方法(Deterministic Maximum Likelihood, DML)完成补偿后目标信号的测向。此方法不但提高了DML方法对低信噪比目标敏感性,而且DML测向算法的引入还加快了迭代收敛速度。此外,本文利用仿真和实测数据对所提方法进行验证,结果表明,在相同信噪比与目标展宽程度下,相较于直接采用结合四阶累积量的DML算法进行DOA估计,本文所提方法的均方根误差减小了4.76°,证明了该方法可有效改善展宽弱目标测向性能。

     

    Abstract: The maneuvering motion of a shipborne High Frequency Surface Wave Radar (HFSWR) platform broadens the target echo signal, resulting in a reduced signal-to-noise ratio (SNR) and the emergence of weak targets, which in turn impairs target detection and direction-of-arrival (DOA) estimation accuracy. To address the DOA estimation problem for broadened weak targets caused by the maneuvering motion of shipborne platforms, this paper proposes a DOA estimation method for broadened weak targets based on iterative motion compensation. The proposed method employs an iterative approximation strategy to integrate the compensation and DOA estimation of target echo signals, thereby overcoming the limitation of conventional compensation methods that require prior knowledge of the target azimuth to achieve optimal compensation. Furthermore, a fourth-order cumulant is introduced to reconstruct the array steering vector, and the Deterministic Maximum Likelihood (DML) method is adopted for DOA estimation of the compensated target signals. This approach not only enhances the sensitivity of the DML method to targets with low SNR but also accelerates the convergence rate of the iteration through the incorporation of the DML algorithm. The proposed method is validated using both simulated and measured data. The results demonstrate that, under identical SNR and target broadening conditions, the root mean square error (RMSE) of the proposed method is reduced by 4.76° compared to the direct application of the DML algorithm combined with fourth-order cumulant for DOA estimation, confirming its effectiveness in improving the DOA estimation performance for broadened weak targets.

     

/

返回文章
返回