The GTD model which can accurately describe high frequency electromagnetic back scattering

is introduced into the MUSIC algorithm as its signal model to replace the traditional signal model of the MUSIC algorithm

and the MUSIC algorithm is improved in some extent.The paper presents that

in the eigen-analysis method

we can utilize the orthogonal property between signal and noise subspace.The improved MUSIC algorithm can accurately estimate the type of the scattering centers as well as the position of them

and finally results in good effects.We also simulate the impact of the spatial smoothing preprocessing method on the orthogonal property between signal and noise subspace

and point out that the spatial smoothing preprocessing method can affect the structure of the noise subspace and that of the signal subspace

so the preprocessing method can influence the estimation of the type of the scattering centers

we should modify the final result of the scattering centers' type.