利用改进的Toeplitz化技术实现米波雷达低仰角测高

由于多径效应的存在，米波雷达低仰角测高时除了收到目标的直达波外，还会收到与直达波相干的地(海)面反射的多径信号。该文提出了两种利用改进的Toeplitz化技术实现米波雷达低仰角测高方法。第1种改进方法不但利用阵列接收数据协方差矩阵的每一行元素构造Toeplitz矩阵，还利用了与其对应每一列元素构造Toeplitz矩阵，然后对这两个矩阵求平均得到一个新的协方差矩阵，这一过程相当于前后向空间平滑的过程，提高了参数估计的精度。第2种改进算法是在第1种算法基础之上，重新构造一个Toeplitz矩阵，使其在信噪比最大约束条件下逼近平滑后协方差矩阵的信号子空间，这样可以最小程度的减小噪声的影响，提高了算法的稳健性。理论分析和计算机仿真都表明了新算法的优越性。

Height Finding of Meter-wave Radar Using Improved Toeplitz Technique at Low-Angle Environment

The echo waves of radar received consist of direct wave and multipath wave which is reflected from earth (sea) surface and coherent with direct wave. Two new height finding algorithms using improved Toeplitz technique at low-angle environment are presented. The first method uses not only every row elements but also corresponding every column elements of array covariance matrix to construct a Toeplitz matrix, a new covariance matrix is obtained taking average these two matrixes, this process is equivalent to spatial smoothing and improves the accuracy of DOA estimation of elevation. The second method based on the first method, reconstructing a Toeplitz matrix to approach the subspace of above covariance matrix constraint to maximum SNR (Signal Noise Ratio), it can reduce the influence of the noise to a certain extent and improve the robust of algorithm. Theoretical analysis and simulation results demonstrate the merits of the new algorithm.