基于协方差矩阵双层重构的稳健自适应单脉冲测角

常规自适应单脉冲方法在主瓣干扰下会引起自适应波束形成性能恶化并导致其单脉冲比曲线严重失真，影响被动雷达的测角精度与跟踪性能。针对此问题，提出了一种适用于平面阵的基于协方差矩阵双层重构的稳健自适应单脉冲测角方法。首先，利用Capon功率谱通过稀疏重构法初步估计出干扰加噪声协方差矩阵，通过干扰导向矢量估计完成对协方差矩阵的优化校正以提高自适应波束形成性能；然后，基于线性约束最小方差(Linearly Constrained Minimum Variance, LCMV)准则对方位角和俯仰角进行联合线性约束以避免单脉冲比曲线在主瓣干扰下严重失真；最后，根据自适应单脉冲比值求出目标与波束指向之间的偏转角以实现目标测角。与常规方法相比，所提方法在干扰抑制能力与测角精度上都有显著提升。

Robust adaptive monopulse angle estimation based on two-step covariance matrix reconstruction

Traditional adaptive monopulse method leads to deterioration of adaptive beamforming performance and serious distortion of monopulse ratio curve in the presence of mainlobe interference,which will affect angle estimation accuracy and tracking performance of passive radar.To solve this problem,a robust adaptive monopulse angle estimation method based on two-step covariance matrix reconstruction is proposed for planar array.Firstly,Capon power spectrum is used to obtain the preliminary estimation of the interference-plus-noise covariance matrix through sparse reconstruction.Secondly,the steering vector of the interference is estimated to complete optimization correction of the covariance matrix in order to improve performance of adaptive beamforming.Then,joint linear constraints of azimuth and elevation are applied based on linearly constrained minimum variance(LCMV) criterion to avoid serious distortion of adaptive monopulse ratio curve.Finally,deflection angle between the target and the beam direction is calculated according to the adaptive monopulse ratio so as to realize target angle estimation.Compared with traditional methods,the proposed method has a great improvement in ability of interference suppression and precision of angle estimation.