The invention provides a target orientation
estimation algorithm based on
covariance matrix imaginary part reconstruction for solving the problems that the
underwater environment is complex and weak signals are difficult to detect. The
algorithm includes calculating a
covariance matrix from array received data; extracting an imaginary part of the
covariance matrix, and reconstructing a new
covariance matrix according to the characteristic value and the corresponding characteristic vector of the imaginary part; initializing a variable factor and a
noise power
estimation value; calculating initial values of a spatial orientation spectrum and sparseness thereof; on the basis of a sparse approximate minimum variance principle, iteratively calculating the spatial orientation spectrum until convergence; normalization
processing is carried out on the iteration space
azimuth spectrum, angles corresponding to the first K maximum values are target
azimuth estimation values, and K is the real number of target signals. According to the method, the
covariance matrix is reconstructed by extracting the
covariance matrix imaginary part, so that the influence of
noise on weak signals is weakened; and on the other hand, the estimation performance of the
weak signal and the sparseness of the
azimuth spectrum are considered by adaptively adjusting the variable factor, and the resolution capability of the weak target is enhanced.