O. V. Afanasyev - C.Sc. (Eng.), Head of Department, JSC «Concern «Sozvezdie» (Voronezh)
S. N. Razin´kov - D.Sc. (Phys.-Math.), Leading Research Scientist, Scientific and Research Test Center of Electronic Warfare, Air Force Academy named after Professor N. E. Zhukovsky and Yu. A. Gagarin. E-mail: razinkovsergey@rambler.ru

In this paper, the mean square error of angular coordinates finding of ultra-wideband radio emission sources in multi-static systems with linear array antennas is studied. This is done basing on spectral representation and maximum likelihood estimates of time-of-arrival of non-harmonic waveforms. Emitters direction finding accuracy dependence on receiving antenna's directivity is studied. It is shown that the bearing estimation's dispersion decreases if the value of integrated product of energy's spectral density of emission and partial directivity factors of transmitting and receiving antennas increases in equivalent frequency band of a signal at the input of measuring device. The analysis of accuracy of a direction finding of emitters in case of engaging a spatial rejection of narrow-band interfering signals by nulls forming in partial antenna patterns with energetic directivity coefficients losses' minimization. Lagrange uncertain multipliers method is used for that. The minimum of energy loss of a signal, which source's bearing is estimated, is reached when forming nulls in partial antenna patterns and maximization of partial directivity factors of arrays.