①School of Information?Engineering, Chang’an University, Xi’an 710064,China; ②National of Lab Radar Signal Processing, Xidian Univ., Xi’an 710071, China
Abstract：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.
2010, Vol. 32 
