ИСТИНА

The method of noise interferometry consists in the correlation processing of the fields registered on the antenna array from incoherent noise sources present in the medium. If such sources are distributed isotropically, then the field coherence function for each pair of points in space makes it possible to determine the difference between the retarded and advanced Green's functions between these points. This can serve as a basis for setting and solving the inverse scattering problem and ultimately determining the medium properties. However, in a number of practical problems (ocean acoustics, geoacoustics, thermoacoustic tomography), the distribution of sources is not isotropic. In the first considered case, a small number of relatively powerful sources are present against the background of isotropically distributed noise sources. A procedure for correcting the eigenvalues of the coherence matrix is proposed. Its application makes it possible to preserve the efficiency of the noise interferometry method. It is shown that slightly better results are obtained when both acoustic pressure and vibrational velocity sensors are used in the antenna array. In the second considered case, some noise sources are controlled, their coordinates and power are known. An iterative algorithm for reconstructing the parameters of the medium directly based on the values of the coherence function is proposed. The results of its work are compared with other known algorithms.