A. A. Vasin - Ph.D. (Eng.), Senior Teacher of Moscow Aviation Institute, Department of Radiophysics, Antennas and Microwave Technique. E-mail: notna_nisav@mail.ru
L. I. Ponomarev - D.Sc. (Eng.), Professor of Moscow Aviation Institute, Department of Radiophysics, Antennas and Microwave Technique. E-mail: mai4062@mail.ru
A. E. Homskov - Ph.D. (Eng.), Head of Department, «STC» Co., Ltd. (St. Petersburg)

The article discusses the experimental results of direction finding with 16-element circular and seven element L-shape antenna arrays. The technique, based on the correlation matrix spectral decomposition, is used to estimate the number, directions of arrival and amplitudes of the strongly correlated signals. Direction finding has been carried out both in the daylight and in the nighttime because the number of the directions of arrival of multipath signals, signal correlation score and wave propagation conditions in HF band during the day differ considerably. It is shown that multipath score may be judged by the shape of the antenna array elements amplitude distribution. Successful calculation of maximum of the functional is made, which includes the signal eigenvector corresponding to the maximum eigenvalue of the correlation matrix of the antenna array input data. It is shown that direction finding of the surface waves from even powerful Earth sources is coupled with specified complications because of the possible appearance of the multiple propagation paths.