A. D. Vinogradov - Dr.Sci. (Eng.), Professor, Senior Research Scientist, Federal State Official Military Educational Institution of Higher Professional Education Military Educational-Research Centre of the Air Force «Air Force Academy named after professor N.E. Zhukovsky and Y.A. Gagarin» (Voronezh). E-mail: mvvad@mail.ru
M. I. Kozlov - Senior Developer, Public Corporation «Concern «Sozvezdie» (Voronezh). E-mail: begun87@mail.ru
А. Y. Mihin - Project Manager, Public Corporation «Concern «Sozvezdie» (Voronezh). E-mail: alemih@mail.ru
G. V. Podshivalova - Ph.D. (Eng.), Head of Department, Public Corporation «Concern «Sozvezdie» (Voronezh). E-mail: Galinawrn@mail.ru

This article evaluates the sensitivity of the direction finder with five- or seven-element circular array antenna basing on the method of moments. Electromagnetic mutual coupling of the antenna elements is taken into account. Energetic signal-to-noise ratio dependence is provided and analyzed in channels of the radio direction finder, as well as the ratio of effective height of the antenna element in array to normalized effective length equal to 1 m and maximum direction finding sensitivity depending on the ratio of the radius of the ring array to the wavelength. Some features of the direction finding algorithm usage are discussed, which are associated with the choice of supporting matrix. It is shown that the basic performance parameters of the direction finder, including its limiting sensitivity, can be obtained by statistical modeling, in which bearing estimation can use the model which does not accounts mutual coupling of array elements and is completely determined solely by geometry of the ring array.