基于分数低阶矩的干涉阵列米波雷达稳健测高方法

限制米波(VHF)雷达低角测高性能的关键因素是波束宽及复杂多径反射信号。该文提出倒T形干涉式阵列以扩展阵列孔径和增加阵列自由度(DOF)，并提出基于分数低阶矩(FLOM)的干涉阵列米波雷达低角稳健测高算法。该算法针对复杂多径信号中非高斯分布的散射分量，从理论上证明分数阶协变矩阵(CM)仍保留阵列流形结构特征，并结合2维空间平滑技术实现分数阶协变矩阵的解相干，再由双尺度酉ESPRIT算法实现稳健低角测高。最后从理论上提出干涉阵列的3区基线设计法。实验结果验证干涉阵列与测高算法的有效性与正确性，说明干涉阵列提高了低角目标分辨性能，也说明了分数低阶矩增强了低角测高算法的稳健性，并验证3区基线设计法的理论正确性。

Robust Height Finding Based on Fractional Lower Order Moments for An Interferometric Array Very High Frequency Radar

Two key factors limiting the performance of height finding of low-elevation targets for Very High Frequency (VHF) are the wider receive beamwidth and complex multipath signals. An T-shaped interferometric array is proposed to extend the receive aperture and increase the Degrees Of Freedom(DOF) for improving the angle resolution. A robust height finding Algorithm based on the Fractional Low Order Moments(FLOM) is proposed. Owing to the non-Gaussian diffuse component, the Covariation Matrix(CM) is demonstrated theoretically for the array manifold reservation by the fractional lower order moments. Then the decorrelation for the generalized signal covariation matrix is performed with spatial smoothing and real-valued transform. The robust low-elevation altitude estimation is achieved by the two-dimensional Unitary ESPRIT algorithm based on the dual-size spatial shift-invariance of the interferometric array. The proposed method increases the resolution between the direct signal and specular multipath. The three-region baseline method is also proposed theoretically. Simulation results demonstrate the validation of the interferometric structure and robust height finding method as well as the theoretical correctness of the three-region baseline method.