一种面向相控阵雷达的多维牛顿正交匹配追踪算法

A Multi-Dimensional Newtonized Orthogonal Matching Pursuit Algorithm for Phased Array Radar

  • 摘要: 传统的脉冲多普勒雷达采用线性信号处理方法实现目标检测和状态估计,具有复杂度低、处理效率高等优点。然而,在临近密集目标等复杂场景情况下,传统方法存在弱目标被强目标旁瓣遮蔽、分辨率受瑞利分辨率限制等问题。压缩感知方法能够充分利用目标在快时间、慢时间、方位、俯仰域四域的稀疏特性,对四域进行网格划分,通过稀疏反演实现目标重构。然而,目标的径向距离、径向速度、方位角和俯仰角都是连续取值的参数,上述网格划分方法存在格点错配、精度受限于格点间隔、虚警率不恒定等问题。为了解决上述问题,本文设计了基于线性调频脉冲信号的牛顿正交匹配追踪算法,提出了一种面向多目标的相控阵雷达多维牛顿正交匹配追踪(multidimensional Newtonized orthogonal matching pursuit for phased array radar,MDNOMP-PAR)算法。该算法利用牛顿法和块坐标下降方法对多目标的径向距离、径向速度、方位角和俯仰角进行循环修正,并基于恒虚警准则设计算法的停止条件,最终确定目标个数。数值实验结果表明,与采用数字波束成形(digital beamforming,DBF)、加窗脉冲压缩(windowed pulse compression,WPC)与动目标检测(moving target detection,MTD)这一传统方法相比,MDNOMP-PAR方法不仅保持了恒虚警检测特性,估计精度提升了至少100%;在雷达距离分辨率为37.5 m的情况下,此方法的分辨力为45 m,相较加窗脉压MTD方法分辨力提升了50 m。此外,在邻近强弱目标场景下,当虚警率设置为10-6时,MDNOMP-PAR方法的弱目标检测性能提升4 dB。

     

    Abstract: Traditional pulse-Doppler radar employs linear signal processing methods for target detection and state estimation, offering advantages such as low complexity and high processing efficiency. However, in complex scenarios as in closely spaced targets, traditional methods encounter challenges such as weak targets being obscured by the sidelobes of strong targets and limitations imposed by the Rayleigh resolution. The compressed sensing (CS) approach effectively leverages the sparsity of targets across four domains: fast time, slow time, azimuth, and elevation. By discretizing these domains into grids, it reconstructs targets through sparse inversion. However, since parameters such as radial distance, radial velocity, azimuth angle, and elevation angle are inherently continuous, grid-based methods face issues that include grid mismatch, resolution constrained by grid spacing, and non-constant false alarm rates. In this study, a multidimensional Newtonized orthogonal matching pursuit algorithm for phased array radar (MDNOMP-PAR) customized for multitarget scenarios is proposed for linear frequency modulation pulse signals. The algorithm iteratively refines the radial distance, radial velocity, azimuth angle, and elevation angle of multiple targets using Newton’s method and block coordinate descent. It also employs a constant false alarm rate (CFAR) criterion to design the stopping condition, ultimately determining the number of targets. Numerical experiments demonstrate that compared with conventional methods—such as digital beamforming (DBF), windowed pulse compression (WPC), and moving target detection (MTD)—MDNOMP-PAR not only retains the CFAR detection characteristics but also improves estimation accuracy by at least 100%; With a spatial resolution of 37.5 m, this method achieved a resolution of 45 m, offering a 50 m improvement in resolution compared to the windowed pulse compression MTD method. Furthermore, in scenarios involving adjacent strong and weak targets, when the false alarm rate was set to 10-6, the weak target detection performance of the MDNOMP-PAR method improved by 4 dB.

     

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